Dissertations / Theses on the topic 'Benthic organisms'

This PhD Thesis deals with the study of marine natural products as candidates in either drug discovery and development. In particular, the investigation focused on benthic organisms, i.e. those fixed or in a close relation with the sea bottom. These organisms, many of which are sessile or slow-moving invertebrates, thus unable to escape quickly from their predators, and devoid of physical protection (shell or hard texture), have developed alternative protective strategies as well as the production of chemical weapons. Compounds involved in the chemical defence, besides the ecological function, can display interesting pharmacological activities. Organisms of different phyla (Algae, Molluscs and Cnidarians) and from diverse geographical areas (Mediterranean Sea and China) were investigated. The benthic diatom Cocconeis scutellum is able to affect the sex reversal in the protandric shrimp Hippolyte inermis, inducing apoptosis (programmed cell death) in the crustacean's androgenic gland. Thus, we wondered whether these diatoms could act also in other crustaceans and on human cancer cells, in order to evaluate their applications in aquaculture and medicine. In fact, some commercially important crustaceans show a bimodal pattern of growth, in which males grow faster and are bigger than females. For this reason, the production of all-male populations is more advantageous. The administration of proapoptotic compounds in an early larval phase could be a method to manipulate the sex in these crustaceans. Nevertheless, our study demonstrated that diatom compounds did not induce apoptosis in the androgenic gland of other species, suggesting a targeted and specific action of C. scutellum metabolites. On the other hand, the biological assays on human cancer cell lines showed that solid tumours were more responsive to C. scutellum than haematological tumours and normal cells, suggesting a specific toxic action of the diatom compounds. In addition, we demonstrated that the most active fraction to induce apoptosis in cancer cells was that containing the highest amount of eicosapentaenoic acid (EPA), described in the literature for its anticancer and proapoptotic properties. This fraction detained the cell cycle at G2/M phase and the results in terms of apoptosis and reduced cell viability produced by this fraction were comparable with those induced by EPA. Western blotting experiments showed that diatoms triggered apoptosis by the extrinsic pathway, i.e. by means of activation of caspase 8, and confirmed the involvement of effector caspase 3. In addition, C. scutellum was studied for the first time from the chemical point of view. By GC-MC we identified more than 100 compounds, mainly fatty acids, sterols and glycerides, and excluded the presence of short chain aldehydes.
In collaboration with the University of Athens, the chemical study on the anaspidean mollusc Aplysia fasciata was carried out. From its digestive and hermaphroditic glands 16 metabolites were isolated by a combination of chromatographic techniques, and they were identified by spectroscopic analysis. Six of them (6-hydroxy-1-brasilene, epibrasilenol acetate, (3Z,9Z)-7-chloro-6-hydroxy-12-oxopentadeca-3,9-dien-1-yne, 6-epi-beta-snyderol, 16-acetoxy-15-bromo-7-hydroxy-9(11)-parguerene), belonging to different classes of sesquiterpene, acetogenin and diterpene compounds, are new and related with metabolites isolated from different species of the red alga Laurencia, the animal's diet.
In the Istituto di Chimica Biomolecolare (Italy), the chemical and biological investigation on the Chinese soft coral Sinularia sp. was performed. We isolated four new casbene compounds, i.e. bicyclic diterpenes characterized by a cyclopropane fused with a 14-membered macrocycle, which are usually found in Euphorbiaceae plants and rarely in marine organisms. Contrastingly to most natural cis ring-fused casbenes, in Sinularia co-existed cis and trans compounds and this suggested a non-stereospecific biosynthetic mechanism. The 4 casbenes were active against Gram+ bacteria and just casbene 3 also against Gram- bacteria, only hydroxylated casbenes displayed anti-feeding properties, and they did not exhibit antiproliferative activity.
"Metabolitos secundarios de organismos bentónicos: aspectos ecológicos y químicos"

Depositada por Michela Nappo

TEXTO:

El objetivo de esta Tesis es el estudio de los productos naturales marinos y su posible relevancia en el desarrollo de nuevos medicamentos. La investigación se enfocó sobre los organismos bentónicos, i.e. los que viven en contacto con el fondo marino y que, a pesar de la falta de protección física y la escasa movilidad de la mayoría de las especies, han desarrollado mecanismos de defensa alternativos, como la producción de armas químicas. Estos compuestos, dotados de propiedades ecológicas, a menudo exhiben también importantes actividades farmacológicas. Se consideraron organismos pertenecientes a diferentes phyla (algas, moluscos y cnidarios) y áreas geográficas. Las diatomeas Cocconeis scutellum afectan la reversión sexual del decápodo proterándrico Hippolyte inermis, induciendo apoptosis (muerte celular programada) en la glándula androgénica del crustáceo. En esta Tesis evaluamos también la capacidad de dichas diatomeas en afectar el cambio de sexo de otros crustáceos, en particular los de interés comercial, y de actuar sobre las células tumorales humanas, a fin de encontrar posibles aplicaciones en acuicultura y medicina. También se valoró el patrón metabólico de las diatomeas mediante cromatografía de gases/espectrometría de masas, identificando más de 100 compuestos (ácidos grasos, esteroles y glicéridos), no constatándose la presencia de aldéhidos de cadena corta.
En la Universidad de Atenas, se realizó el estudio químico del molusco anaspídeo Aplysia fasciata. Mediante diferentes técnicas cromatográficas y espectroscópicas, se aislaron 16 metabolitos, de los cuales seis eran nuevos (6-hidroxi-1-brasileno, epibrasilenol acetato, (3Z,9Z)-7-cloro-6-hidroxi-12-oxopentadeca-3,9-dien-1-ino, 6-epi-beta-snyderol, 16-acetoxi-15-bromo-7-hidroxi-9(11)-parguereno), relacionados con metabolitos de algas rojas del género Laurencia, que constituyen la dieta del animal.
En el Instituto de Química Biomolecular (Pozzuoli, Italia) se realizó tanto el estudio químico como los experimentos biológicos con el coral blando Sinularia sp. procedente de China. De esta especie se aislaron 4 nuevos compuestos casbénicos (diterpenos bicíclicos formados por un anillo ciclopropánico fusionado a un macrociclo de 14 átomos) cuya estructura es frecuente en plantas de la familia Euphorbiaceae y bastante más rara en los organismos marinos. Los casbenos hidroxilados eran repelentes alimenticios; todos son activos frente a las bacterias Gram+ y sólo el casbeno 3 es también activo frente a las bacterias Gram- .

L’applicazione di organismi bioindicatori, per descrivere possibili cambiamenti dovuti a impatti antropici o naturali, è aumentata negli ultimi decenni grazie all’implementazione della legislazione Europea (es., Water Framework Directive, Marine Strategy). In quest’ottica il monitoraggio periodico delle comunità marine assume un ruolo cruciale. Obiettivo di questo progetto è stato la caratterizzazione delle comunità a idroidi (Cnidaria:Hydrozoa) e spugne (Porifera) delle isole di Montecristo e Giglio, appartenenti al Parco Nazionale dell’Arcipelago Toscano destinato a futura istituzione come Area Marina Protetta. Oltre ad aumentare le conoscenze sulle comunità marine delle due isole, i risultati ottenuti sono stati resi disponibili agli stakeholders per informarli sulle specie dei gruppi considerati presenti nell’area, sperando che possa essere d’aiuto nell’implementazione di nuove strategie di protezione. Inoltre, è stata condotta una revisione sistematica sull’applicazione di organismi bentonici (spugne, cnidari, briozoi, policheti, cirripedi, tunicati), proposti come bioindicatori non-convenzionali di elementi in tracce per le aree marine costiere. Infatti, ulteriore obiettivo del progetto è stato quello di esplorare il ruolo dei poriferi come bioindicatori di inquinamento da mercurio (Hg), tramite un’analisi multilivello (dalla comunità al gene). Grazie a uno studio preliminare su diverse specie, alcune sono state suggerite come migliori bioindicatori, tra cui Chondrosia reniformis, considerata per analisi successive. Infine, è stato esplorato il ruolo del microbiota associato alle spugne nei processi di bioaccumulo, per poter proporre questi organismi nella bioremediation. Oltre ad una caratterizzazione della comunità microbica di C. reniformis, quantità considerevoli di Hg sono state ritrovate all’interno del microbiota stesso, suggerendo suo un coinvolgimento non solo nel metabolismo secondario delle spugne, ma anche nei processi di bioaccumulo di Hg.
Periodic biodiversity assessments are of fundamental importance for describing possible changes in marine communities caused by natural or anthropogenic impacts. The application of different organisms as bioindicators of impacts and pollution has increased in the last decades thanks to the implementation of the European legislation (e.g., Water Framework Directive, Marine Strategy). In this context, the aim of this PhD project was to assess the hydroid (Cnidaria:Hydrozoa) and sponge (Porifera) communities of Montecristo and Giglio, two islands belonging to the Tuscan Archipelago National Park aimed to become a future Marine Protected Area. These data improve the knowledge on the zoobenthic communities of the studied area and have been also made available to stakeholders and policy makers, to inform them on the hydroid and sponge species present in the studied area, possibly helping in the implementation of new protection strategies. A systematic review was also conducted on the application of benthic organisms (sponges, cnidarians, bryozoans, polychaetes, cirripeds, tunicates), suggested as non-conventional bioindicators of trace elements in coastal shallow waters. In fact, this project also deepens the application of Porifera as biomonitoring tools for mercury (Hg) pollution, with a multi-level analysis (from the community to the individual). Thanks to a preliminary study on different species, a few were suggested as better bioindicators of Hg, among them the species Chondrosia reniformis, which was considered for further analysis. In addition, the role of sponges’ associated microbiota in the bioaccumulation processes was explored to identify these organisms also as useful tools in the bioremediation. The microbial community of the C. reniformis was characterized, and considerable amount of metal were detected in the microbiota itself, suggesting its possible implication not only in the secondary metabolism of the sponge but also in the bioaccumulation of Hg.

S'ha estudiat l'estructura i dinàmica del sistema bentònic de llacunes costaneres de la maresma dels aiguamolls de l'Empordà (NE de la península Ibèrica) i els factors que les determinen. Amb aquesta finalitat es van prendre mostres d'organismes del bentos (mensualment), nutrients i pigments de l'aigua (setmanalment) i el sediment (mensualment), així com paràmetres físics de l'aigua (setmanalment), durant dos cicles d'inundació (1997-1998 i 1998-1999).
En aquesta maresma els factors determinants per als organismes bentònics i el contingut en nutrients del sediment són principalment físics: el grau de permanència de l'aigua, el confinament i la granulometria. De manera que els factors tròfics tenen menys pes que els físics tal com es posa de manifest amb les associacions de nematodes. El règim hídric de les llacunes integra des del grau de permanència de l'aigua fins a la salinitat i el confinament, per la qual cosa a partir de la caracterització dels diferents tipus de règim hídric es poden discriminar les tres tipologies d'ambients amb comunitats bentòniques diferenciades en l'estructura, la composició i la dinàmica temporal. Així, les tres comunitats diferenciades són: (1) la d'aigües permanents caracteritzada per una riquesa i diversitat elevades i constants en el temps, i per un nombre més elevat de tàxons sense adaptacions per passar situacions adverses; (2) la d'aigües semipermanents i temporànies d'inundació pulsativa, caracteritzada per una menor riquesa i diversitat, i per la dominància d'organismes amb estructures de resistència per passar la fase seca i aguantar condicions desfavorables, i (3) la d'aigües temporànies d'inundació continuada, caracteritzada per una major variabilitat de la riquesa i diversitat al llarg del cicle i per una singularitat taxonòmica més elevada, ja que s'observen cladòcers i una major representació taxonòmica dels insectes.
Durant la realització d'aquest estudi els dos cicles d'inundació van suposar entrades d'aigua en el sistema diferents, per això es va diferenciar un cicle humit (1997-1998) i un de sec (1998-1999). En relació amb la major importància de les entrades d'aigua en el sistema, es va observar un contingut en nutrients de l'aigua significativament superior durant el cicle humit. Pel que fa al sediment, la seva major inèrcia explicaria la manca de diferències significatives en el contingut en nutrients del sediment del cicle humit i del sec. Ara bé, sí que s'observa diferència en la composició d'organismes. Així, la variabilitat interanual en l'estructura de la comunitat bentònica de la maresma es pot atribuir a una situació d'estrès provocada pel cicle sec. Aquesta situació va comportar un augment de la diversitat per disminució de la dominància a totes les llacunes estudiades, determinada, en gran manera, per la disminució de l'abundància original de poblacions dominants i característiques d'ambients permanents, Corophium orientale, o temporànies, Gammarus aequicauda.

No existeix un patró estacional en les comunitats estudiades, sinó que els principals canvis en el plàncton i el bentos són deguts a pertorbacions hídriques. Aquestes pertorbacions provoquen que s'estableixi una situació en què dominen uns tàxons característics en el plàncton (Synchaeta i Eutintinnus) i, en canvi, que en el bentos es perdi l'estructura pròpia de les comunitats característiques dels diferents ambients (comunitats dominades per Corophium orinetale en aigües permanents i per Chironomus salinarius en temporànies). La severitat és diferent en funció del grau de permanència de l'aigua, i és més alta en ambients permanents i més baixa en els temporanis. La major severitat en ambients permanents ve determinada per la menor adaptació del bentos d'aigües permanents a les fluctuacions ambientals i a l'efecte de la predació sobre el plàncton. A més, tant en el bentos com en el plàncton es donen fenòmens d'histèresi, segons els quals l'efecte de la pertorbació no solament depèn de la causa pertorbadora sinó també de l'estat en què es troba la comunitat en el moment de la pertorbació.
The structure and dynamic of the benthic system, and the main factors that control this system have been studied in coastal basins of the Empordà wetlands (NE Iberian Peninsula). During two hydroperiods (1197-1998; 1998-1999) organisms and sediment samples (nutrient and pigment analysis) have been taken monthly, and water samples (nutrient and pigment analysis) and physic and chemical parameters (Tª, Conductivity, Oxygen and pH) have been taken weekly.

In these wetlands benthic organisms and sediment nutrient content were mainly determined by physics factors as water permanence, confinement and granulometry. Trophic factors were less important for the benthic communities than physics ones, as it has been shown by the nematodes associations. Based on the hydrological pattern, three types of basins are distinguished: permanent waters (type 1), temporary waters with pulse water inputs (type 2), and temporary waters with continuous water inputs (type 3). These three types are in agreement with the classification resulting from the benthic communities composition. The type 1 basins, where the more stable environemental conditions were found, had a community characterized by a high density of individuals, total biomass and diversity. The community of type 2 basins had lower richness and diversity values with little temporal variability. Organisms with resistant structures to pass the dry phase and survive adverse conditions were dominant in these community. The high frequency of freshwater inputs in type 3 basins causes a high taxonomic singularity and high temporal variability of species richness and diversity in these basins.
The water input in the wetlands was significantly different for the two hydroperiods studied, so we can distinguish a wet hydroperiod (1197-1998) and a dry hydroperiod (1998-1999). Significantly higher nutrient content in the water was observed related to more important water entrance during the wet hydroperiod. The lack of significant differences on nutrient content of sediment between hydroperiods could be explained by a higher inertia in the benthic system. Differences in faunal composition were observed between hydroperiods. Thus, the interannual variability in the benthic community structure could be attributed to the stress situation caused by the dry hydroperiod. This situation implies a diversity increase due to a highest evenness because the dominant species decrease its relative abundance.
The main plankton and benthos changes were due to hydrological perturbations, so seasonal patterns did not have any relevance to the studied communities. In the plankton community hydrological perturbations caused a new situation (situation dominated by Synchaeta and Eutintinnus), while in the benthos communities provokes a lost of the characteristic structure (characteristic structure were communities dominated by Corophium orientale in permanent waters, and by Chironomus salinarius in temporary waters). The severity varied depending on water permanence, so it was higher in permanent systems and lower in temporary ones. The higher severity in permanent systems was conditioned by the low adaptation to environmental fluctuations of the benthos which lives in permanent waters, and to the effect of predation on the plankton community. Moreover, histeresy phenomenons were observed, since the effects of perturbation were not only caused by the perturbation but also by the community status when the perturbation started.

Thesis (M.S.) -- University of Maryland, College Park, 2005.
Thesis research directed by: Marine, Estuarine, Environmental Sciences Graduate Program. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

Studying the interactions between environmental variables and marine organisms is fundamental to understanding these delicate dynamic balances at different space-time scales. These processes are in constant mutual influence since the biotic compartment undergoes abiotic factors but simultaneously modifies the environmental parameters through their own physiological activities. Nevertheless, each of these drivers, taken individually, is the result of precise balances involving single organisms, communities or entire ecosystems, and multiple environmental parameters can be directly correlated with each other. In an age of climate change such as the one we live in, a multidisciplinary approach to the study of the environments and marine organisms appears essential to understand the potential effect of a single part of the system on the others and, consequently, to try to relate to each other, all of these, to optimally manage ecosystems and safeguarding habitats. Benthic marine species, both sessile for the entire duration of their life cycle or linked to the seabed only for part of it, undergo the effect of physic-chemical changes in the water column and through their adaptations can oppose or support them, sometimes exploiting them to advantage, thanks to their resilience and resistance. On the other hand, the same substrate can be modified by different processes of various nature (mechanical, physical, chemical, biological), thus becoming an essential element that can influence the phases of colonization and consequent larval settlement, on the development of the single organism, and the entire benthic community, up to the point of characterizing the submerged landscape. Furthermore, all these aspects have both a very different spatial and temporal scale; therefore, the observation of the interaction phenomena between organisms and environmental variables requires very different approaches, often conducted step by step, to isolate the effect of a single factor and, where this is not possible, mitigate the interaction. The substrate characteristics have already been considered in many scientific fields, ranging from engineering to ecology, highlighting innovative aspects and conflicting conclusions. Furthermore, the interest in bio-mineralogy, i.e., the study of the interaction between the organism and the mineralogical composition of the substrate, began to emerge at the end of the last century, focusing on the toxic effect of the quartz present in the dissolved sediment on colonization phase of the associated fauna. Since then, numerous studies have deepened this area of research, investigating the hard substrates of various kinds and the structure of the communities settled there. Here, the continuation of this research has attempted to define what effects the substrate can have at different ecological scales (from the single organism to the community, up to the landscape), examining different types of rocks and highlighting affinities between similar lithotypes. Due to their natural geological conformation, the Ligurian coast and the Sardinian context of the Tavolara Marine Protected Area - P.ta Coda Cavallo have been investigated. Particularly, this last locality presents, on a reduced spatial scale, the variability of substrates as well as environments of great environmental value. These contexts have proved to be optimal for expanding knowledge on the effect of the mineralogical composition of lithotypes on the distribution and abundance of benthic organisms, pointing out the crucial role of encrusting coralline algae in stabilising substrates. In a second analysis, the survey made it possible to characterize ecologically and deepen the knowledge on the distribution and the state of health and conservation of priority habitats of great environmental value, currently under-valued and subject to substantial impacts by fisheries, indicating new more suitable for the management of these by the competent Bodies.

O presente trabalho teve como objetivo realizar um estudo dos níveis de concentração e da distribuição das espécies metálicas Arsênio, Cádmio, Crômio, Cobre, Níquel e Chumbo em água, sedimento e nos organismos bentônicos dos rios e reservatórios pertencentes à Rede de Monitoramento de água e sedimento da CETESB, utilizando as técnicas analíticas de espectrometria de absorção atômica com atomização em forno de grafite (GF AAS) e espectrometria de emissão ótica (ICP OES). Paralelamente, avaliou-se a toxicidade da água e do sedimento para a bactéria Vibrio fischeri e a comunidade bentônica local. A caracterização multielementar (concentração total) dos sedimentos pela técnica de análise por ativação neutrônica (NAA) também foi realizada. Todas as metodologias analíticas foram avaliadas quanto à precisão, exatidão e os limites de detecção e quantificação foram calculados. Nas amostras de água, foram obtidas concentrações dos metais analisados inferiores aos limites estipulados pela Resolução 357/2005 do CONAMA para corpos de água classe 2. Os elementos estudados foram determinados, muitas vezes em concentrações que podem causar efeitos adversos à biota aquática, nas amostras de sedimento de dez dos treze pontos estudados, o que sugere que estes elementos tendem a se depositar nos sedimentos. Obtiveram-se concentrações dos elementos Cd, Cu, Pb e Ni em muitas das amostras de invertebrados bentônicos estudados, demonstrando que estes elementos podem ser absorvidos e bioacumulados nos organismos expostos aos sedimentos contaminados. A correlação entre as concentrações dos elementos no sedimento e nos organismos foi significativa e positiva. As correlações entre as concentrações dos elementos detectados e a massa dos organismos também foram significativas, porém negativas, ou seja, quanto menor a massa, maiores concentrações são esperadas. Não foi detectada toxicidade aguda nas amostras de água para o Vibrio fischeri, porém foi detectada na água intersticial de oito das treze amostras de sedimento testadas. Quanto à avaliação da comunidade bentônica, um ponto foi classificado como qualidade Ruim, oito como Regular e quatro como Boa, segundo critério adotado pela CETESB. Os resultados obtidos na análise de sedimentos por análise por ativação neutrônica demonstraram existir valores mais enriquecidos para os elementos As, Br, Cr, Hf, Ta, Th , U e Zn e os elementos terras raras (ETR) Ce, Eu, La, Nd, Sm, Tb e Yb em muitas das amostras analisadas indicando que pode estar havendo contribuição antrópica para esses elementos.
The present study analyzed concentration levels and distribution of As, Cd, Cr, Cu, Ni and Pb metallic species in water, sediment and aquatic organisms in rivers and reservoirs of a water and sediment quality monitoring network belonging to CETESB. For this purpose two analytical techniques Graphite Furnace Atomic Absorption Spectrometry (GF AAS) and Optical Emission Spectrometry with Inductively Coupled Plasma (ICP OES) were used. Water and sediment toxicity for Vibrio fischeri bacteria and the local benthic community were also evaluated. The multielemental characterization of sediments was undertaken by neutron activation analysis technique (NAA). All the analytical methodologies were evaluated for precision and accuracy, and detection and quantification limits calculated. In water samples metal concentrations were below the CONAMA 357/2005 resolution limits for class 2 water bodies. For sediment samples metal concentration levels that can cause adverse effects on aquatic biota were found in 10 of the 13 collection points studied. Metals Cd, Cu, Pb and Ni were detected in many invertebrate benthic organisms samples studied, indicating that these elements can be absorbed and bioaccumulated by these organisms when exposed to contaminated sediments. Significant correlations were found for metal concentrations in sediments and organisms. Negative correlations between detected element concentrations and weight of the sampled organisms were significant, so that the lower the weight the higher metal concentrations were measured. Acute toxicity for Vibrio fischeri was not observed for the water samples, but was detected in 8 of the 13 sediment interstitial water samples tested. As for the benthic community evaluation, one of the 13 points was rated as BAD quality, 8 rated as REGULAR and 4 as GOOD, using CETESB´s classification. The results for sediment samples by NAA showed higher enrichment values for As, Br, Cr, Hf, Ta, Th , U e Zn and rare earth elements (REE) Ce, Eu, La, Nd, Sm, Tb and Yb in many of the tested sediment samples indicating that there may be and anthropic contribution for these elements.

The contamination and degradation of many sediment environments have been attributed to the global surge of anthropogenic activities near coastlines. Organism-sediment interactions (i.e. bioturbation) are known to alter sediment biogeochemistry and potentially increase the risk of contaminant exposure and toxicity to surrounding ecosystems. Current risk assessment frameworks for contaminated sediments seldom consider the impacts of bioturbation on contaminant exposure explicitly, leading to potentially inaccurate assessments and ineffective management strategies. In this thesis, the impacts of bioturbation on benthic organism exposure and toxicity were assessed. The impacts of bioturbation on: (i) metal bioaccumulation and toxicity in the bivalve Tellina deltoidalis in metal contaminated sediments; and, (ii) toxicity (survival and reproduction) in the amphipod Melita plumulosa in sediments contaminated by primarily metals and a mixture of metals and hydrocarbons are addressed in Chapters 2 and 3, respectively. In both studies, increased bioturbation intensities (presence of the amphipod Victoriopisa australiensis) in metalcontaminated sediments resulted in large differences in metal partitioning between the sediment and overlying water column, although the degree of partitioning varied for different metals. Lower toxicity in both T. deltoidalis (survival) and M. plumulosa (survival and reproduction) bioassays with increased bioturbation was attributed to lower copper exposure. In contrast, for sediments contaminated by both metals and hydrocarbons, high bioturbation intensities enhanced toxicity, and was attributed to increased bioavailability of polycyclic aromatic hydrocarbons (PAHs). Both studies demonstrated that bioturbation modifies the concentrations and forms of metals in the particulate and dissolved phase, altering exposure and toxicity to cohabiting organisms. Greater bioturbation intensities were shown to increase metal exposure (due to disruption of contaminant binding) or decrease metal exposure by providing a source of contaminant sequestration in the water column via sediment resuspension and/or increased efflux of dissolved pore water metals. Therefore, overall sediment toxicity may either be increased or decreased depending on the types of organism, bioturbation intensity and contaminants present, and indicates the need to consider such interactions when assessing the risks contaminated sediments pose to aquatic environments. The fourth chapter of this thesis investigated the influence of bioturbation (absence/presence of T. deltoidalis and V. australiensis) on metal bioavailability and toxicity to M. plumulosa (survival and reproduction) in a metal contaminated sediment with different concentrations of acid volatile sulfides (AVS). Acid volatile sulfides are considered a major metal binding phase in anoxic sediments, and the molar difference between AVS and simultaneously extractable metals (SEM, where SEM=Cd+Cu+Ni+Pb+Zn). SEM-AVS is commonly used by environmental scientists and managers to predict risk of effects of these common metal contaminants in sediments. However, such chemical-extraction methods do not consider how organisms burrowing behaviours may modify metal bioavailability in sulfidic sediments, and this is typically not discussed when evaluating the significance of SEM-AVS results. Bioturbation resulted in lower AVS concentrations through oxidation and increased SEM concentrations. Similar to Chapters 2 and 3, toxicity to reproduction was lower in the more highly bioturbated sediments that contained low AVS and corresponded with lower dissolved copper and zinc concentrations in the overlying water column and tissues of M. plumulosa. In contrast, greater bioturbation resulted in higher toxicity in the sediments that contained high AVS, despite lower dissolved copper and zinc concentrations. These results indicate that the AVS-SEM paradigm cannot be accurately used to predict low risk of toxicity in sediments bioturbated or mechanically reworked during remediation. The addition of bioturbators to degraded sediments can either immobilise contaminant stressors or mobilise and facilitate their removal, potentially facilitating further recruitment of benthic organisms assisting in restoring functioning ecosystems. The fifth chapter of this thesis investigated the tolerance of bioturbating organisms to hypersalinity, another common physicochemical stressor in many degraded coastal ecosystems. In order to utilise bioturbators to assist with hypersaline sediment remediation, salinity tolerance thresholds need to be determined for a variety of benthic organisms. Hypersaline sediments (~400‰ salinity) collected from decommissioned salt ponds were used to delineate the salinity threshold limits for a range of benthic organisms to better understand their role in remediation strategies for removing stressors such as hypersalinity. The results from this study identified the tolerances for a range of benthic organisms to hypersaline sediments and enabled the extrapolation of a range of salinity limits, above which recolonisation by bioturbating organisms may be inhibited. This information is critical for designing monitored natural recovery strategies to restore hypersaline sediments to functioning ecosystems. Collectively, the research in this thesis has illustrated the importance of considering organismsediment interactions within existing sediment quality assessment frameworks and management strategies. Bioturbation by benthic organisms has been shown to alter the biogeochemistry and toxicity of many common contaminants in sediments. These changes can either be positive or negative for the resident biota. Despite these differences, the presence of bioturbation in contaminated sediments may reduce the concentration of sediment contaminants over time, and ultimately lead to sediment recover and rehabilitation.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
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Este trabalho fez parte de um projeto FAPESP (Projeto QualiSed), onde foram envolvidas três instituições paulistas (UFSCar, UNICAMP, CETESB) e que teve como intuito levantar dados para a futura derivação Valores – Guias de Qualidade de Sedimentos (VGQS) para metais e compostos orgânicos xenobióticos. O objetivo específico deste trabalho é o de gerar dados para a derivação de VGQS para metais (Cd, Cu, Pb, Ni e Zn) em cinco represas do Rio Tietê, represas Billings, Rasgão, Barra Bonita, Bariri e Promissão. Os estudos foram direcionados à caracterização biogeoquímica dos sedimentos desses ambientes através das determinações das concentrações dos nutrientes totais e sulfetos volatilizáveis por acidificação (SVA), do estudo da partição de metais entre os sedimentos totais as águas intersticiais, e da determinação da fração de metais associada aos SVA nos sedimentos totais, denominada metais estraidos simultameamente ou MES. Os dados levantados foram interpretados em associação aos resultados da estrutura da comunidade bentônica e testes de toxicidade. Foi realizada também, uma avaliação e identificação da toxicidade (AIT) (do inglês, TIE: Toxicity Identification Evaluation) com sedimentos da Represa de Rasgão. Este procedimento se baseia na toxicidade causada após um esquema de fracionamento e manipulações químicas da matriz para caracterizar (Fase I), identificar (Fase II) e confirmar (Fase III) os compostos específicos ou classes destes, responsáveis pela toxicidade da amostra. Em uma série de experimentos de laboratório foram realizados também bioensaios com os organismos Hyalella azteca e Tubifex tubifex, em sedimentos com adição de metais (do inglês, spiking), utilizando-se sedimentos da Represa de Promissão. Os resultados deste trabalho mostraram que, os níveis de concentração de nutrientes nas represas estudadas são altos (C total: 3 – 6%; N total: 0,3 – 1,3%; P total e 0,2 – 0,5%), o que é uma indicação de que esses ambientes encontram-se eutrofizados. As concentrações dos MES apresentaram a tendência de um gradiente de concentração, diminuindo a concentração de metais nos sedimentos das represas da capital para o interior (ora ocorrendo uma inversão entre Barra Bonita e Bariri). Atribuiu-se esta inversão à descarga de esgotos provenientes da entrada dos rios Jaú e Bauru na represa de Bariri. Para o SVA o mesmo gradiente foi observado, ocorrendo também uma inversão entre Barra Bonita e Bariri. A aplicação do VGQS da fase sólida ou do SVA, preconizado pela USEPA, mostrou que os metais são controlados pela fase sulfídrica nos sedimentros das represas Billings, Rasgão, Barra Bonita ou pelo carbono orgânico total (COT) nas represas de Bariri e Promissão. O Valor Guia de Unidades Tóxicas de Águas Intersticiais (VGUTAI), também preconizado pela USEPA, aplicado aos sedimentos das diferentes represas foi violado por todas elas. Neste caso, esses valores devem ser comparados com os testes de toxicidade, pois mesmo em casos onde o VGUTAI é violado, a toxicidade pode não ser devido aos metais dos sedimentos. Da mesma forma que no VGQS do SVA, pode estar havendo um controle por fases ligantes na água intersticial (ligantes dissolvidos) que agem atenuando a biodisponibilidade e conseqüentemente a toxicidade. Avaliando-se os resultados dos estudos de adição de metais em sedimento, apenas as represas Rasgão e Billings atingiram a faixa de concentração onde houve manifestação de efeitos nos experimentos de fortificação de metais. Tais resultados estão também em concordância com o VGQS do Canadá. No entanto, esses ambientes possuem um estoque de sulfetos que estariam bioindisponibilizando os metais e portanto, estes contaminantes não estariam causando efeitos deletérios à biota local. Os resultados de AIT com os sedimentos da Represa de Rasgão são uma surpresa somente no que diz respeito a substâncias ou grupo deles que causa a toxicidade (amônia) dado que foi detectada a presença de concentrações significativas de metais e compostos orgânicos neste ambiente. Os dados são um alerta aos órgãos públicos responsáveis pela gestão de recursos hídricos do Estado de São Paulo e devem servir de base para o estabelecimento de medidas ou ações eficazes na contenção do avanço da degradação da qualidade em cascata das represas do Rio Tietê. O conjunto de dados levantados por este estudo em associação aos demais levantados pelo Projeto QualiSed (UFSCar-UNICAMP-CETESB) formaram a base para a proposição de um programa de avaliação integrada e hierárquica da qualidade de sedimentos (AIHQS), onde os VGQS em uso no Canadá e EUA são usados como valores orientadores de determinadas ações (análises físicas, químicas, biológicas e ecotoxicológicas) tomadas nas diferentes etapas do programa (árvore de decisão).
This work was part of a project FAPESP (QualiSed Project), where three institutions from São Paulo were involved (UFSCar, UNICAMP, CETESB) and that had as intention to lift data for the future derivation of Sediment Quality Values Guidelines (SQVG) for metals and xenobiotic organic compounds. The specific objective of this work is to generate data for the derivation of SQVG for metals (Cd, Cu, Pb, Ni and Zn) in five dams of Tietê River, Billings, Rasgão, Barra Bonita, Bariri and Promissão. The studies were addressed to the biogeochemical characterization of the sediments of those environments through the determinations of the concentrations of the total nutrients and acid volatile sulfide (AVS), the study of the partition of metals among the total sediments and interstitials waters, the determination of the fraction of metals associated with AVS in the total sediments. The lifted up data were interpreted in association to the results of the structure of the benthic community and toxicity tests. It was also accomplished, an Toxicity Identification Evaluation (TIE) with sediments from Rasgão Dam. These procedures use toxicity-based fractionation schemes to characterize (Fase I), to identify (Fase II) and to confirm (Fase III) the compounds responsible for the toxicity of the sample. In a series of laboratory experiments Hyalella azteca and Tubifex tubifex were also used in bioessays with spiked sediments, being used sediments from Promissão Dam. The results of this work showed that, the levels of concentration of nutrients in the studied dams are high (total C: 3 - 6%; total N: 0,3 - 1,3%; total P and 0,2 - 0,5%), what is an indication that those environments are eutrophicated. The concentrations of the SEM presented the tendency of a concentration gradient, decreasing the concentration of metals in the sediments of the dams of the capital to the interior (however happening an inversion between Barra Bonita and Bariri). This inversion was attributed to the discharge of coming sewers of the entrance of the rivers Jaú and Bauru in the Bariri Dam. For AVS the same gradient was observed, also happening an inversion between Barra Bonita and Bariri. According to the solid phase SQVG, praised for USEPA, metals are controlled by sulfídric phase (Billings, Rasgão, Barra Bonita) or by total organic carbon (TOC) (Bariri and Promissão). The interstitial water value guide toxic Units (IWVGTU), applied to the different dams was violated by all studied environments. In this case, those values should be compared with the toxicity tests, because even in cases where the IWVGTU is violated, the toxicity cannot be due to the metals of the sediments. In the same way that in AVS SQVG, it can be having a control for binding phases in the pore water (ligands dissolved) that act attenuating the bioavailability and consequently the toxicity. Evaluating the results of the studies of metal spiking in sediment, only the dams of Rasgão and Billings had reached the concentration strip where there was manifestation of effects in the experiments of metal spiking. Such results are also in agreement with SQVG of Canada. However, those environments possess a sulfides stock that would be unbioavailabling the metals and therefore, these pollutants would not be causing deleterious effects to the local aquatic organisms. The results from TIE with the sediments from Rasgão Dam are a surprise only in respect to the substances or group of them that cause the toxicity (ammonia) given that the presence of significant concentrations of metals and organic compounds was detected and found in this environment. The data are an alert to the responsible public agencies for the administration of hydric resources of the State of São Paulo and they should serve as base for the establishment of measures or effective actions in the contention of the progress of the degradation of the quality in cascade of Tietê River´s dams. The data from this study in association to others data from the QualiSed Project (UFSCar-UNICAMP-CETESB) formed the base for the proposition of a program of sediment quality hierarchical and integrated evaluation (SQHIE), where SQVG in use in Canada and USA are used as guidelines values to some actions (physical analyses, chemistries, biological and ecotoxicological) in the different stages of the program (decision tree).

The objective of this research was to determine if physical and microbial sediment characterizations could be used to explain benthic macroinvertebrate distribution in two branches of Lake Ray Roberts, Texas.

Invasive species are second only to habitat loss as a leading cause of native species displacement and the management of invasive species costs hundreds of billions annually. Invasion is often conceptualized as a series of stages (Transport, Introduction, Establishment, and Spread), which encourages ecologists to isolate factors that might enable a species to pass from one stage to another and therefore guide prevention or impact management. This thesis addresses each stage of invasion and attempts to determine where management might succeed in preventing invasion or minimizing impacts. The transport and introduction of aquatic invasive species (AIS) was analyzed by conducting a three tier human subjects survey at Tenmile Lake, Oregon over a two year period in which a public boat wash station was built and installed. Assessing boater knowledge of AIS and understanding proper boat cleaning procedure is useful in determining the threat of transport and introduction as overland boater movements is a major vector of AIS. The comparison between pre- and post- boat wash surveys indicate that there is a disconnect between what boaters say they will do and how they actually behave. While 75.9% of boaters from the pre-survey claimed they would use a boat wash station at Tenmile Lake, only 38.5% of post-survey boaters were observed using the station. Furthermore, the surveys identified knowledge gaps of boaters' awareness of AIS. More than 20.0% of boaters surveyed could not verbally name any AIS. To better understand the establishment and spread stages of invasion, I examined the influence of a specific AIS, the New Zealand mud snail (Potamopyrgus antipodarum; NZMS), on benthic food webs throughout three very different aquatic ecosystems (lakes, rivers, and estuaries). Samples of benthic lake, river, and estuarine invertebrates were collected, identified, and counted, and stable isotope analyses (SIA) were conducted on several components of the food web. NZMS densities were found to be dynamic, with population densities fluctuating over time and between locations. A significant negative relationship between NZMS density and community diversity across all ecosystems was found. However, the densities of specific feeding groups had varying positive (omnivores) and negative (herbivores) correlations with NZMS densities. Furthermore, SIA indicated that NZMS don't appear to be competing with native macroinvertebrates for the same food source. NZMS were found to have different influences on each invaded ecosystem, thus management of this particular AIS is difficult once established and spreading. The results of this thesis suggest that prevention of the transport and introduction of NZMS needs to be the focus for future management. Preventative management should include public outreach regarding AIS and proper boat cleaning procedure, and management should also emphasize the need for regional policies and regulations on the transport of AIS rather than site or state specific policies and regulations.

Le comportement joue un rôle crucial dans la survie des organismes en leur permettant de s'adapter à leur environnement particulièrement variable. De nos jours, les réponses comportementales des organismes aux changements environnementaux doivent faire face à des défis sans précédents en raison des changements rapides et néfastes provoqués par l'ère Anthropique. En particulier, la pollution plastique se distingue comme l'une des préoccupations les plus pressantes dans les habitats marins. Au-delà des dommages physiques évidents, les plastiques peuvent libérer un cocktail nocif de molécules chimiques, compromettant les organismes marins à de nombreux niveaux. Liant les individus au fonctionnement des écosystèmes et aux processus évolutifs, le comportement des organismes reste cependant peu étudié dans la littérature sur l'impact des lixiviats de plastique. Ce travail de thèse vise à combler les lacunes existantes dans la littérature en ce qui concerne les organismes et les polymères étudiés. Après une revue approfondie de la littérature, ce travail se concentre sur l'étude de l'impact des lixiviats de plastique, issus de bio-polymères et de polymères conventionnels sur les comportements liés à l'anxiété chez le crabe Hemigrapsus sanguineus, les comportements de déplacement du foraminifère Haynesina germanica et les comportements cirraux de la balane Austromonius modestus. Les résultats révèlent des modifications significatives de ces comportements, qui dépendent de l'espèce, du type de polymère et de la concentration des lixiviats, et compromettent l'équilibre délicat de l'écosystème. Notamment, le lixiviat de bio- polymère entraine des altérations comportementales similaires, voire plus prononcées, que ceux issus de polymères conventionnels, soulevant des inquiétudes significatives quant à la sécurité environnementale des alternatives aux plastiques
Behaviors play a pivotal role in organisms' survival, enabling organisms to cope with their ever-changing environment. Nowadays, adaptive behavioral responses to environmental changes face unprecedented challenges due to the rapid and detrimental effects of the Anthropocene era. Noticeably, plastic pollution stands out as one of the most pressing concerns in marine habitats. Beyond causing conspicuous physical damages, plastics may leach a cocktail of harmful chemicals impairing marine organisms at various levels. Despite its role in connecting individuals to ecosystem functioning and evolutionary processes, organism behavior remains scarcely studied in the plastic leachate literature. This PhD thesis aims at to address the gaps in existing literature concerning the organisms and polymers considered. After an extensive review of the plastic leachate literature, this work focuses on investigating the impact of plastic leachates from both bio and conventional polymers on the anxiety-related behaviors of the crab Hemigrapsus sanguineus, the motion behaviors of the foraminifera Haynesina germanica and the cirral activity of the barnacle Austrominius modestus. The results reveal significant modifications in behaviors, highlighting species, polymer and dose dependencies, posing a threat to the delicate ecosystem balance. Noticeably, the biopolymer leachate results in similar or even more behavioral alterations than leachates from conventional polymers, raising significant concerns about the environmental safety of plastic alternatives

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The objective of this project was to investigate the impact of different pesticides used in the ricefield on the density and diversity of benthic organisms. In the experiment, two collects of soil were made to identify and quantify benthic organisms, one in the 28th and other in the 84th days after the entry of water in the ricefield. We used a cylindrical collector of PVC (Curer) with 0.10 m in diameter (0.01 m2) at a depth of 0.10 m. Samples were collected in the irrigated plots that received the following treatments: TO - Imazethapyr + Imazapic (ONLY ®), TB - Bispyribac-sodium (NOMINEE 400SC), TQ - Quinclorac (FACET PM), TF - Fipronil (STANDACK) and TC - control. The number of replicates for each treatment was 12 samples per day. The collected material was stored in plastic bags and taken to the laboratory, where it was washed in sieves of 0.25 mm and re-packed in plastic bottles and then immediately stained (Rose-Bengal), and fixed with absolute ethanol. After fixing, the organisms were separated and identified to the lowest taxonomic level possible, using specialized bibliographies. Throughout the period of ricefield, data on the following parameters of irrigation water were recorded: dissolved oxygen, pH, temperature, alkalinity, hardness, turbidity, conductivity and persistence of pesticides used. To verify differences in the physical-chemical, between treatments, we used a TWO-WAY-ANOVA (treatment and time) and a PCA. An ANOVA one criterion was used to verify differences in taxa between treatments and a MANOVA was used to examine differences in fauna composition between treatments and trophic guilds. There were no differences among abiotic data and the treatment, but differences were found in the time of cultivation. Concerning the persistence of pesticides, the herbicide quinclorac was the most persistent, detected up to the 84th day. The lower persistence of the herbicide ONLY® was detected until the 21st day. In the first sample a total of 1971 animals was collected from all treatments, separated into four phyla: Arthropoda (Insecta, Arachnida and Crustacea), Mollusca (Gastropoda), Anellida (Oligochaeta and Hirudinea) and Nematoda. In the second group of samples, 2295 individuals were identified among all treatments. The same phyla were present, but the diversity of insects was higher than in the previous collection. The MANOVA showed differences between the fauna composition of the treatments evaluated, and between collections, as well as among the fauna composition of the same trophic guild in the different treatments. Based on these results we conclude that the pesticides did not affect the physical and chemical parameters of water, however, these products can cause stress on the benthic community at the beginning of culture for a period of approximately one month after the entry of water in the plots. This effect is reduced over time so that the benthic community tends to restructure after the period of greatest activity of pesticides in water.
O objetivo deste estudo foi investigar o impacto da utilização de diferentes agroquímicos, empregados na lavoura de arroz irrigada por inundação, sobre a densidade e riqueza de organismos bentônicos. No experimento, foram realizadas duas amostragens de solo para identificar e quantificar organismos bentônicos, uma no 28º e outra no 84º dia após a entrada de água na lavoura. Utilizou-se um coletor cilíndrico de PVC (Corer) com 0,10 m de diâmetro (0,01 m2) na profundidade de 0,10 m. As amostragens foram realizadas em parcelas que receberam os seguintes tratamentos: TO -imazethapyr + imazapic (ONLY®); TB - bispyribac-sodium (NOMINEE 400SC); TQ - quinclorac (FACET PM); TF - fipronil (STANDACK) e TC - controle. O número de réplicas para cada tratamento foi de 12 amostras por dia amostral. O material coletado foi armazenado em sacos plásticos e levado para o laboratório, onde foi lavado em peneiras de 0,25mm, reacondicionado em frascos plásticos e logo em seguida corado (Rosa-de-Bengala) e fixado com álcool etílico absoluto. Após a fixação os organismos foram triados e identificados até o menor nível taxonômico possível, utilizando-se bibliografias especializadas. Durante todo o período da cultura do arroz foram registrados os dados dos seguintes parâmetros da água de irrigação: Oxigênio dissolvido, pH, temperatura, alcalinidade, dureza, turbidez, condutividade e persistência dos pesticidas utilizados. Para verificar diferenças quanto aos fatores físico-químicos, entre os tratamentos, utilizou-se uma ANOVA de dois critérios (tratamento e tempo) e uma PCA. Uma ANOVA de um critério foi utilizada para verificar diferenças dos táxons entre os tratamentos e uma MANOVA foi empregada para analisar diferenças na composição da fauna entre os tratamentos e guildas tróficas. Não se observou diferenças nos dados abióticos em relação aos tratamentos, mas sim em relação ao tempo de cultivo. Com relação à persistência dos pesticidas, o herbicida Quinclorac foi o mais persistente, detectado até o 84º dia. A menor persistência foi do herbicida Only, detectado até o 21º dia. Na primeira amostragem foram coletados um total de 1971 organismos entre todos os tratamentos, pertencentes a quatro filos: Arthropoda (Insecta, Arachnida e Crustacea), Mollusca (Gastropoda), Anellida (Hirudinea e Oligochaeta) e Nematoda. Na segunda coleta foram identificados 2295 organismos entre todos os tratamentos. Os mesmos filos estiveram presentes, porém a riqueza de insetos foi maior que na coleta anterior. A Manova mostrou haver diferenças entre as composições da fauna dos tratamentos avaliados, e entre as coletas, bem como na composição da fauna, de uma mesma guilda trófica, nos diferentes tratamentos. Com base nestes resultados é possível concluir que os pesticidas utilizados não afetaram os parâmetros físico-químicos da água, entretanto, esses produtos podem causar estresse na comunidade bentônica no início da cultura, por um período de aproximadamente um mês após a entrada de água nas parcelas. Este efeito é reduzido com o passar do tempo, de maneira que a comunidade bentônica tende a se reestruturar após o período de maior ação dos pesticidas na água.

Les activités anthropiques causent des invasions biologiques qui sont devenues un problème mondial susceptible de causer des dommages écologiques (p. ex., sur la biodiversité et l’habitat), économiques (sur les industries) et sociaux (sur le bien-être humain). La prévention et la détection précoce des nouvelles invasions sont des éléments essentiels pour la gestion des risques et des impacts sur les écosystèmes et les économies. Bien sûr, la prévention est préférable, mais la détection précoce est une étape cruciale pour enrayer la propagation ultérieure des espèces envahissantes, car elle offre la possibilité de les éradiquer avant les phases d’établissement de la population et de propagation. Bien qu’il s’agisse d’une option de gestion efficace en matière de coût et de temps, la détection précoce exige un effort d’échantillonnage considérable pour détecter les populations envahissantes aux tout premiers stades de leur invasion. En utilisant le système benthique marin comme modèle, quatre études interdépendantes ont été menées pour identifier des stratégies d’échantillonnage susceptibles d’améliorer notre capacité à détecter des populations envahissantes rares et à comprendre les patrons et processus écologiques de recrutement benthique à multiples échelles spatiales et temporelles. Plus précisément, ces études expérimentales sur le terrain visaient à (1) évaluer la relation entre l’approvisionnement en larves et la fixation dans une population envahissante isolée, (2) déterminer la durée de l’échantillonnage et de la fréquence à l’aide de plaques de fixation pour la détection d’espèces rares, (3) déterminer l’importance relative aux sources de variations spatiales et temporelles du recrutement benthique, et (4) examiner l’effet de l’échelle spatiale de l’échantillonnage sur la détection des espèces en analysant les patrons de recrutement à de multiples échelles sur quatre ordres de grandeur allant de la dizaine de mètres à la dizaine de kilomètres. Première étude : contrairement à l’hypothèse originale d’une relation étroite entre l’approvisionnement et la fixation initiale, l’approvisionnement en larves était plutôt un facteur déterminant de la fixation aux échelles moyennes. Ces résultats suggèrent que la force de cette relation s’affaiblit avec l’augmentation de l’échelle spatiale des observations de terrain. Néanmoins, un quart de la variation de la fixation à moyenne échelle peut encore être expliqué par l’approvisionnement sur des courtes échelles de temps (une semaine). Par conséquent, cette relation confirme l’utilité des plaques de fixation en tant qu’outil efficace pour la détection précoce aux échelles moyennes dans une marina, car une faible densité de recrutement sur les plaques correspond à une faible abondance de propagules envahissantes dans la colonne d’eau...
Les activités anthropiques causent des invasions biologiques qui sont devenues un problème mondial susceptible de causer des dommages écologiques (p. ex., sur la biodiversité et l’habitat), économiques (sur les industries) et sociaux (sur le bien-être humain). La prévention et la détection précoce des nouvelles invasions sont des éléments essentiels pour la gestion des risques et des impacts sur les écosystèmes et les économies. Bien sûr, la prévention est préférable, mais la détection précoce est une étape cruciale pour enrayer la propagation ultérieure des espèces envahissantes, car elle offre la possibilité de les éradiquer avant les phases d’établissement de la population et de propagation. Bien qu’il s’agisse d’une option de gestion efficace en matière de coût et de temps, la détection précoce exige un effort d’échantillonnage considérable pour détecter les populations envahissantes aux tout premiers stades de leur invasion. En utilisant le système benthique marin comme modèle, quatre études interdépendantes ont été menées pour identifier des stratégies d’échantillonnage susceptibles d’améliorer notre capacité à détecter des populations envahissantes rares et à comprendre les patrons et processus écologiques de recrutement benthique à multiples échelles spatiales et temporelles. Plus précisément, ces études expérimentales sur le terrain visaient à (1) évaluer la relation entre l’approvisionnement en larves et la fixation dans une population envahissante isolée, (2) déterminer la durée de l’échantillonnage et de la fréquence à l’aide de plaques de fixation pour la détection d’espèces rares, (3) déterminer l’importance relative aux sources de variations spatiales et temporelles du recrutement benthique, et (4) examiner l’effet de l’échelle spatiale de l’échantillonnage sur la détection des espèces en analysant les patrons de recrutement à de multiples échelles sur quatre ordres de grandeur allant de la dizaine de mètres à la dizaine de kilomètres. Première étude : contrairement à l’hypothèse originale d’une relation étroite entre l’approvisionnement et la fixation initiale, l’approvisionnement en larves était plutôt un facteur déterminant de la fixation aux échelles moyennes. Ces résultats suggèrent que la force de cette relation s’affaiblit avec l’augmentation de l’échelle spatiale des observations de terrain. Néanmoins, un quart de la variation de la fixation à moyenne échelle peut encore être expliqué par l’approvisionnement sur des courtes échelles de temps (une semaine). Par conséquent, cette relation confirme l’utilité des plaques de fixation en tant qu’outil efficace pour la détection précoce aux échelles moyennes dans une marina, car une faible densité de recrutement sur les plaques correspond à une faible abondance de propagules envahissantes dans la colonne d’eau...
Les activités anthropiques causent des invasions biologiques qui sont devenues un problème mondial susceptible de causer des dommages écologiques (p. ex., sur la biodiversité et l’habitat), économiques (sur les industries) et sociaux (sur le bien-être humain). La prévention et la détection précoce des nouvelles invasions sont des éléments essentiels pour la gestion des risques et des impacts sur les écosystèmes et les économies. Bien sûr, la prévention est préférable, mais la détection précoce est une étape cruciale pour enrayer la propagation ultérieure des espèces envahissantes, car elle offre la possibilité de les éradiquer avant les phases d’établissement de la population et de propagation. Bien qu’il s’agisse d’une option de gestion efficace en matière de coût et de temps, la détection précoce exige un effort d’échantillonnage considérable pour détecter les populations envahissantes aux tout premiers stades de leur invasion. En utilisant le système benthique marin comme modèle, quatre études interdépendantes ont été menées pour identifier des stratégies d’échantillonnage susceptibles d’améliorer notre capacité à détecter des populations envahissantes rares et à comprendre les patrons et processus écologiques de recrutement benthique à multiples échelles spatiales et temporelles. Plus précisément, ces études expérimentales sur le terrain visaient à (1) évaluer la relation entre l’approvisionnement en larves et la fixation dans une population envahissante isolée, (2) déterminer la durée de l’échantillonnage et de la fréquence à l’aide de plaques de fixation pour la détection d’espèces rares, (3) déterminer l’importance relative aux sources de variations spatiales et temporelles du recrutement benthique, et (4) examiner l’effet de l’échelle spatiale de l’échantillonnage sur la détection des espèces en analysant les patrons de recrutement à de multiples échelles sur quatre ordres de grandeur allant de la dizaine de mètres à la dizaine de kilomètres. Première étude : contrairement à l’hypothèse originale d’une relation étroite entre l’approvisionnement et la fixation initiale, l’approvisionnement en larves était plutôt un facteur déterminant de la fixation aux échelles moyennes. Ces résultats suggèrent que la force de cette relation s’affaiblit avec l’augmentation de l’échelle spatiale des observations de terrain. Néanmoins, un quart de la variation de la fixation à moyenne échelle peut encore être expliqué par l’approvisionnement sur des courtes échelles de temps (une semaine). Par conséquent, cette relation confirme l’utilité des plaques de fixation en tant qu’outil efficace pour la détection précoce aux échelles moyennes dans une marina, car une faible densité de recrutement sur les plaques correspond à une faible abondance de propagules envahissantes dans la colonne d’eau. Deuxième étude : des durées d’échantillonnage intermédiaires d’une à deux semaines (l’échelle des traitements allant d’un jour à un mois) étaient la durée optimale de déploiement de la plaque de fixation pour la détection des espèces « rares » (c’est-à-dire, des le début du recrutement). Une analyse au niveau de l’assemblage montre toutefois que l’augmentation de la durée et de la fréquence de l’échantillonnage augmentait logarithmiquement le nombre total d’espèces rares observées. Ces résultats espèce par espèce et au niveau de l’assemblage démontrent que la modification des éléments temporels de l’échantillonnage, tels que la durée et la fréquence, peut affecter considérablement la détection d’espèces. Troisième étude : après avoir évalué plusieurs sources spatiales et temporelles (le site, la région, la saison, et l’année), le moment choisi pour le déploiement des plaques est apparu comme étant la plus grande source de variabilité du recrutement benthique d’espèces rares. En particulier, le moment optimal pour la détection précoce serait en automne (a) lorsque le recrutement saisonnier d’espèces envahissantes établies tend à atteindre un pic et (b) lorsque la détection au niveau du site d’espèces envahissantes rares tend à se produire. Quatrième étude : l’échelle spatiale dominante dans le recrutement d’espèces rares est la plus petite (centaine de mètres). Cette échelle dominante peut être interprétée comme étant la bonne échelle spatiale pour la détection d’espèces rares. Une analyse plus poussée a montré que si l’échantillonnage a été structuré de manière aléatoire, l’échantillonnage à des échelles intermédiaires (millier de mètres) devient l’échelle optimale pour la détection d’espèces rares. Ces résultats élucident les différences de variabilité naturelle de la population benthique entre multiples échelles d’espace et de temps pour des espèces rares et communes. Ces études écologiques font partie d’une boîte à outils de détection précoce nécessaire à la gestion des espèces envahissantes marines en renseignant sur la manière dont l’échantillonnage des espèces rares doit être faite à multiples échelles spatio-temporelles. Des expériences de terrain similaires optimisant la détection d’espèces rares (au-delà de l’utilisation de plaques de fixation pour détecter les organismes benthiques dans les provinces Maritimes canadiennes) devraient être réalisées pour d’autres taxons, régions, t outils d’échantillonnage—en particulier, les envahisseurs à haut risque prévus, les invasions futures, et les outils récemment développés.
Les activités anthropiques causent des invasions biologiques qui sont devenues un problème mondial susceptible de causer des dommages écologiques (p. ex., sur la biodiversité et l’habitat), économiques (sur les industries) et sociaux (sur le bien-être humain). La prévention et la détection précoce des nouvelles invasions sont des éléments essentiels pour la gestion des risques et des impacts sur les écosystèmes et les économies. Bien sûr, la prévention est préférable, mais la détection précoce est une étape cruciale pour enrayer la propagation ultérieure des espèces envahissantes, car elle offre la possibilité de les éradiquer avant les phases d’établissement de la population et de propagation. Bien qu’il s’agisse d’une option de gestion efficace en matière de coût et de temps, la détection précoce exige un effort d’échantillonnage considérable pour détecter les populations envahissantes aux tout premiers stades de leur invasion. En utilisant le système benthique marin comme modèle, quatre études interdépendantes ont été menées pour identifier des stratégies d’échantillonnage susceptibles d’améliorer notre capacité à détecter des populations envahissantes rares et à comprendre les patrons et processus écologiques de recrutement benthique à multiples échelles spatiales et temporelles. Plus précisément, ces études expérimentales sur le terrain visaient à (1) évaluer la relation entre l’approvisionnement en larves et la fixation dans une population envahissante isolée, (2) déterminer la durée de l’échantillonnage et de la fréquence à l’aide de plaques de fixation pour la détection d’espèces rares, (3) déterminer l’importance relative aux sources de variations spatiales et temporelles du recrutement benthique, et (4) examiner l’effet de l’échelle spatiale de l’échantillonnage sur la détection des espèces en analysant les patrons de recrutement à de multiples échelles sur quatre ordres de grandeur allant de la dizaine de mètres à la dizaine de kilomètres. Première étude : contrairement à l’hypothèse originale d’une relation étroite entre l’approvisionnement et la fixation initiale, l’approvisionnement en larves était plutôt un facteur déterminant de la fixation aux échelles moyennes. Ces résultats suggèrent que la force de cette relation s’affaiblit avec l’augmentation de l’échelle spatiale des observations de terrain. Néanmoins, un quart de la variation de la fixation à moyenne échelle peut encore être expliqué par l’approvisionnement sur des courtes échelles de temps (une semaine). Par conséquent, cette relation confirme l’utilité des plaques de fixation en tant qu’outil efficace pour la détection précoce aux échelles moyennes dans une marina, car une faible densité de recrutement sur les plaques correspond à une faible abondance de propagules envahissantes dans la colonne d’eau. Deuxième étude : des durées d’échantillonnage intermédiaires d’une à deux semaines (l’échelle des traitements allant d’un jour à un mois) étaient la durée optimale de déploiement de la plaque de fixation pour la détection des espèces « rares » (c’est-à-dire, des le début du recrutement). Une analyse au niveau de l’assemblage montre toutefois que l’augmentation de la durée et de la fréquence de l’échantillonnage augmentait logarithmiquement le nombre total d’espèces rares observées. Ces résultats espèce par espèce et au niveau de l’assemblage démontrent que la modification des éléments temporels de l’échantillonnage, tels que la durée et la fréquence, peut affecter considérablement la détection d’espèces. Troisième étude : après avoir évalué plusieurs sources spatiales et temporelles (le site, la région, la saison, et l’année), le moment choisi pour le déploiement des plaques est apparu comme étant la plus grande source de variabilité du recrutement benthique d’espèces rares. En particulier, le moment optimal pour la détection précoce serait en automne (a) lorsque le recrutement saisonnier d’espèces envahissantes établies tend à atteindre un pic et (b) lorsque la détection au niveau du site d’espèces envahissantes rares tend à se produire. Quatrième étude : l’échelle spatiale dominante dans le recrutement d’espèces rares est la plus petite (centaine de mètres). Cette échelle dominante peut être interprétée comme étant la bonne échelle spatiale pour la détection d’espèces rares. Une analyse plus poussée a montré que si l’échantillonnage a été structuré de manière aléatoire, l’échantillonnage à des échelles intermédiaires (millier de mètres) devient l’échelle optimale pour la détection d’espèces rares. Ces résultats élucident les différences de variabilité naturelle de la population benthique entre multiples échelles d’espace et de temps pour des espèces rares et communes. Ces études écologiques font partie d’une boîte à outils de détection précoce nécessaire à la gestion des espèces envahissantes marines en renseignant sur la manière dont l’échantillonnage des espèces rares doit être faite à multiples échelles spatio-temporelles. Des expériences de terrain similaires optimisant la détection d’espèces rares (au-delà de l’utilisation de plaques de fixation pour détecter les organismes benthiques dans les provinces Maritimes canadiennes) devraient être réalisées pour d’autres taxons, régions, t outils d’échantillonnage—en particulier, les envahisseurs à haut risque prévus, les invasions futures, et les outils récemment développés.
As a consequence of anthropogenic activities, biological invasions have become a global problem that can cause ecological (e.g., biodiversity and habitat), economic (industries), and social (human wellbeing) harm. Prevention and early detection of new invasions are vital components of managing risks and impacts to ecosystems and economies. Prevention is, of course, preferred but early detection is a critical step that can ultimately stop future spread of invasive species because it provides an opportunity for eradication before population growth and spread. Despite being a cost- and time-effective management option, early detection requires considerably high sampling effort to detect incipient invasive populations at the early stages of their invasion. Using the marine benthic system as a model, four inter-related studies were carried out to identify sampling strategies that could enhance our ability to detect rare invasive populations and to understand ecological patterns and processes of benthic recruitment across multiple scales of space and time. Specifically, these experimental field studies aimed to (1) evaluate the relationship between propagule supply and settlement in a closed invasive population, (2) determine the optimal sampling duration and frequency using settlement plates to detect rare species, (3) ascertain the relative importance of spatial and temporal sources of variation in benthic recruitment, and (4) examine how the spatial scale of sampling affects species detection by analyzing recruitment patterns at multiple scales across four orders of magnitudes ranging from tens of metres to tens of kilometres. First study: Contrary to the expectation of a strong relationship between supply and initial settlement, larval supply was instead a limited determinant of settlement at mesoscales. This finding suggests that the strength of this relationship weakens as the spatial scale increased from previously reported small-scale field observations to mesoscales of the present study. Nonetheless, a quarter of the variation in settlement can still be explained by supply over short timescales (one week). Therefore, this relationship supports the utility of settlement plates as an effective tool for early detection at mesoscales within a marina because low densities of recruitment on plates correspond to low abundances of invasive propagules in the water column...
As a consequence of anthropogenic activities, biological invasions have become a global problem that can cause ecological (e.g., biodiversity and habitat), economic (industries), and social (human wellbeing) harm. Prevention and early detection of new invasions are vital components of managing risks and impacts to ecosystems and economies. Prevention is, of course, preferred but early detection is a critical step that can ultimately stop future spread of invasive species because it provides an opportunity for eradication before population growth and spread. Despite being a cost- and time-effective management option, early detection requires considerably high sampling effort to detect incipient invasive populations at the early stages of their invasion. Using the marine benthic system as a model, four inter-related studies were carried out to identify sampling strategies that could enhance our ability to detect rare invasive populations and to understand ecological patterns and processes of benthic recruitment across multiple scales of space and time. Specifically, these experimental field studies aimed to (1) evaluate the relationship between propagule supply and settlement in a closed invasive population, (2) determine the optimal sampling duration and frequency using settlement plates to detect rare species, (3) ascertain the relative importance of spatial and temporal sources of variation in benthic recruitment, and (4) examine how the spatial scale of sampling affects species detection by analyzing recruitment patterns at multiple scales across four orders of magnitudes ranging from tens of metres to tens of kilometres. First study: Contrary to the expectation of a strong relationship between supply and initial settlement, larval supply was instead a limited determinant of settlement at mesoscales. This finding suggests that the strength of this relationship weakens as the spatial scale increased from previously reported small-scale field observations to mesoscales of the present study. Nonetheless, a quarter of the variation in settlement can still be explained by supply over short timescales (one week). Therefore, this relationship supports the utility of settlement plates as an effective tool for early detection at mesoscales within a marina because low densities of recruitment on plates correspond to low abundances of invasive propagules in the water column...

To determine the relationship between the abundance and density of benthic invertebrates, and the critical shear stress of individual grain sizes, a reach along Smith Creek, was divided into ten 2m x 2m quadrants. Within each quadrant, five randomly selected clasts for each grain size ranging from 2.26 to 25.6 cm were cleaned for benthic invertebrates. Wolman pebble counts for each quadrant were also conducted and used to determine the critical Shields stress per grain size fraction from the model given by Wiberg and Smith (1987) that explicitly accounts for particle hiding/sheltering effects in mixed-bed rivers. Particle entrainment values were then compared with estimated bankfull Shields stress values to determine sediment transport potential during bankfull flow. Invertebrate abundance was strongly positively correlated with critical Shields stress up to the 18.0 cm grain size, indicating a preference for certain grain sizes; while density was positively correlated with all grain sizes present.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico
Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ
Nos últimos anos observa-se um aumento crescente das atividades humanas, tanto científicas quanto turísticas, no ambiente antártico, sendo motivo de preocupação considerando-se que a Antártica é um ambiente de lenta recuperação. Ainda são escassos os estudos sobre o estabelecimento de relações entre a presença de contaminantes e seus efeitos na biota antártica. A contaminação pode ocorrer por processos antrópicos ou naturais e os efeitos destes impactos podem ser detectados e monitorados através da análise das alterações nas comunidades bentônicas. Estas comunidades podem ser consideradas boas indicadoras de impactos ambientais, já que possuem uma relação direta com a origem dos contaminantes acumulados nos sedimentos. Este trabalho avaliou os níveis de metais-traço encontrados no sedimento e em duas espécies circumpolares da megafauna bentônica antártica, a estrela-domar Odontaster validus e o molusco bivalve Laternula elliptica, com a finalidade de determinar se as mesmas podem ser utilizadas como indicadoras de impacto ambiental. Durante o verão austral de 2005/2006 foram realizadas coletas através de diferentes procedimentos, entre 15 e 40m de profundidade, em cinco estações dentro da Área Antártica Especialmente Gerenciada da Baía do Almirantado, Ilha Rei George: 1) Estação Antártica Comandante Ferraz; 2) Botany Point; 3) Punta Ullman; 4) Punta Plaza e 5) Refúgio II. Os seguintes metais foram quantificados tanto para o sedimento quanto para os organismos: Al, V, Cr, Mn, Fe, Ni, Cu, Cd, Ba, Pb e Zn. A concentração de metais variou entre os diferentes compartimentos corpóreos analisados. Para a espécie O. validus, as maiores concentrações de metais-traço (Mn, Ni, Cd, Ba, Pb) e do macronutriente Al, foram encontradas na parede do corpo. Cu, Cr, V e Zn apresentaram maior concentração no estômago, enquanto o macronutriente Fe concentrou-se preferencialmente nos cecos pilóricos. Para a espécie L. elliptica, as maiores concentrações de metais-traço (Mn, V, Ba, Cu) e dos macronutrientes Fe e Al, foram encontradas no sifão. Cd, Ni, Pb e Zn apresentaram maior concentração no rim enquanto o Cr foi mais concentrado no compartimento restos. A concentração de elementostraço nos compartimentos corpóreos de O. validus e L. elliptica não foi influenciada pelo tamanho do organismo (peso total do indivíduo).
Once the Antarctic environment has low recovery rates, the recent growth in the touristic and scientific activities is a serious issue for the scientific community. Few studies have tried to establish the links between the presence of contaminants and the antarctic biota. The contamination may be related to human or natural processes, and be monitored trough the benthic communities. These communities have a direct relation with the contaminants sources in the sediment. The present work analyzed the trace-metals levels found in the sediment and two circumpolar benthic megafauna species in Antarctica, the starfish Odontaster validus and the Antarctic clam Laternula elliptica. The objective was to establish if these species can be used as environmental indicators. Five stations was occupied during the austral summer of 2005/2006, between 15 and 40m deep, in the Antarctic Special Management Area of Admiralty Bay, George King Island: 1) Comandante Ferraz Antarctic Base; 2) Botany Point; 3) Punta Ullman; 4) Punta Plaza and 5) Refúgio II. Analyzes were conducted to quantify the presence of Al, V, Cr, Mn, Fe, Ni, Cu, Cd, Ba, Pb and Zn, both in the sediment and organisms. The metals concentrations vary in the different body compartments. Larger concentrations of (Mn, Ni, Cd, Ba, Pb) trace metals and Al macronutrient were found in the body walls of O. validus. Cu, Cr, V and Zn showed larger concentrations in the stomach and the Fe macronutrient in the caeca pyloric. For L. elliptica, larger trace metals (Mn, V, Ba, Cu) and macronutrients (Fe and Al) concentrations were found in the sifon, while Cd, Ni, Pb and Zn showed larger concentrations in the kidney. Cr presented larger concentrations in the remains compartment. The concentrations of trace elements in both O. validus and L. elliptica were not influenced by the body size (total individual weight).

Os estudos apresentados nesta tese tiveram como objetivo compreender aspectos da organização de assembleias de algas bênticas em riachos. Foi avaliado especificamente o efeito da heterogeneidade de habitat na escala de rugosidade de substratos e sua interação com distúrbios hidrológicos e organismos pastejadores (grazers). Utilizou-se uma abordagem experimental in situ com substratos lisos e rugosos (com fendas) constituindo os tratamentos. Os experimentos foram conduzidos no Rio do Marco, um riacho de quarta ordem na região dos Campos de Cima da Serra, em São José dos Ausentes, Rio Grande do Sul. Após uma introdução geral acerca do assunto são apresentados os capítulos com os estudos. O Capítulo 1 avaliou os efeitos da rugosidade de substratos sobre a riqueza de espécies, densidade, composição e padrões de distribuição de assembleias de algas bênticas. Assembleias em substratos rugosos foram mais ricas que assembleias em substratos lisos, porém esse resultado diferiu entre grupos com diferentes formas de vida, assim como as diferenças na composição de espécies, indicando que somente alguns grupos foram beneficiados pela ocorrência de refúgios em substratos rugosos. Observou-se também que diferenças na composição da assembleia entre substratos lisos e rugosos resultaram de aninhamento e substituição de espécies. No Capítulo 2 foi testada a hipótese de que substratos rugosos abrigam assembleias mais persistentes que substratos lisos. Os resultados encontrados confirmaram esta hipótese e foram atribuídos ao efeito da rugosidade per se após a exclusão de alguns fatores de confundimento, como estabilidade física dos substratos e diferenças na riqueza de espécies. Concluiu-se que o mecanismo mais plausível para explicar a maior persistência em substratos rugosos é a maior disponibilidade de refúgios em relação a substratos lisos. O objetivo do Capítulo 3 foi avaliar o efeito da rugosidade de substratos sobre assembleias de algas frente a um distúrbio hidrológico experimental, testando especificamente se a resistência e a resiliência de algas é maior em substratos rugosos que em substratos lisos e se a resposta de diferentes formas de vida é distinta. Os resultados indicaram que a rugosidade de substratos não apresenta efeitos pronunciados sobre a resistência e a resiliência de algas bênticas. Porém, grupos de algas com distintas formas de vida diferiram quanto à resistência e resiliência, de forma que o padrão observado está relacionado a atributos biológicos que conferem habilidades para suportar distúrbios. Os resultados deste estudo em conjunto com os resultados obtidos no Capítulo 2 e resultados obtidos por outros autores permitiram que fosse proposto que a importância da heterogeneidade de habitas e de refúgios é mediada pela intensidade de distúrbios. No Capítulo 4 foram avaliados os efeitos independentes e as interações de rugosidade de substratos, peixes pastejadores e tipos de mesohabitats (corredeiras e remansos) sobre a biomassa algal, matéria orgânica e peso seco total. O efeito de peixes pastejadores não foi mediado pelos mesohabitats, sendo que a exclusão de peixes causou aumento nas três variáveis resposta, independente do tipo de mesohabitat. Por outro lado, houve uma interação entre mesohabitats e substratos para determinar o acúmulo de peso seco total, sendo que substratos rugosos acumularam maior quantidade de material em remansos que em corredeiras, enquanto substratos lisos acumularam quantidades similares entre os dois tipos de mesohabitats. Já a biomassa algal e matéria orgânica apresentaram maior acúmulo nos substratos rugosos em relação aos lisos, independente do mesohabitat. Os resultados encontrados indicam que a perda de organismos pastejadores pode afetar o acúmulo de biomassa algal e material orgânico, importantes recursos alimentares em riachos. Finalmente, na última seção são apresentadas as considerações finais.
The studies presented in this thesis aimed at understanding some aspects of the organization of benthic algal assemblages in streams. Specifically, the studies evaluated the effect of habitat heterogeneity on the scale of substrate roughness and its interaction with hydrological disturbances and grazing organisms. An experimental in situ approach was used, in which the treatments were constituted by smooth and rough (with crevices) substrates. The experiments were conducted in the Marco River, a fourth-order stream at the region of Campos de Cima da Serra, São José dos Ausentes, Rio Grande do Sul, Brazil. After a general introduction on the subjects of this thesis, the chapters with the studies are presented. The Chapter 1 describes a study to evaluate the effects of substrate roughness on species richness, density, composition and distribution patterns of benthic algal assemblages. Algal assemblages on rough substrates were richer than on smooth substrates, but this result differed among algal life forms. Similarly, results on species composition also differed among life forms, indicating that only some groups were benefited by the occurrence of refuges on rough substrates. It was also observed that differences in the composition of assemblages between rough and smooth substrates resulted from nestedness and turnover. The Chapter 2 describes a study in which was tested the hypothesis that rough substrates harbor more persistent assemblages than smooth substrates. The results confirmed this hypothesis and were attributed to the effect of roughness per se after the exclusion of some confounding factors, such as the physical stability of substrates and differences in species richness. It was concluded that the most plausible mechanism that could explain the higher persistence in rough substrates is the greater availability of refuges in relation to smooth substrates. The main aim of the study described in Chapter 3 was to evaluate the effect of substrate roughness on algal assemblages in the face of an experimental hydrological disturbance. Specifically, it was tested if the resistance and resilience of algae is higher on rough than on smooth substrates and if algal life forms differ in their response to disturbance. The results indicated that substrate roughness had no pronounced effects on benthic algal resistance and resilience. However, algal life forms differ in their resistance and resilience, and the observed pattern was mostly related to biological traits that confer abilities to support disturbances. The results of this study, in addition to the results obtained in Chapters 1 and 2, allowed us to suggest that the importance of habitat heterogeneity and refuges is mediated by the intensity of disturbances. The Chapter 4 describes a study that evaluated the independent and interacting effects of substrate roughness, grazing fish and mesohabitats (pools and riffles) on algal biomass, organic matter and total dry mass accrual. The effect of grazers was not mediated by mesohabitats, and their exclusion caused an increase in the three response variables, regardless of mesohabitat. On the other hand, mesohabitats and substrates interacted to determine the accrual of total dry mass, since rough substrates accumulated greater amounts of dry mass in pools than in riffles, while smooth substrates accumulated similar amounts in both mesohabitats. Algal biomass and organic matter showed greater accrual on rough than on smooth substrates, independently of mesohabitat. These results indicate that the loss of grazers may affect the accrual of algal biomass and organic matter, which are important food resources in streams. Finally, in the last section are presented the concluding remarks.

Le principal objectif de cette thèse était de mieux comprendre l’importance des Substances Polymériques Extracellulaires (SPE) dans la structuration et la formation des biofilms benthiques ; tout en s’inscrivant dans une étude plus globale des mécanismes écologiques impliqués dans le fonctionnement des vasières intertidales. La mise au point des dosages biochimiques a été effectuée sur le mucilage de l’algue Chaetomorpha aerea et a permis en parallèle de purifier un polysaccharide sulfaté riche en galactose, présentant une activité bactéricide sélective contre la souche Staphylococcus aureus (ATCC 25923). Les études biochimiques et écologiques menées sur les SPE extraits de la vasière charentaise ont ensuite permis de quantifier leur dynamique de production et leur composition, en fonction des conditions environnementales. La présence de désoxy-sucres et d’acides uroniques au sein des SPE capsulaires a laissé supposer que ces fractions jouaient un rôle important dans la formation et le devenir du biofilm microphytobenthique. La dernière partie des travaux a permis de caractériser les propriétés acide/base de Lewis et hydrophile/hydrophobe de la surface de la micro-algue Navicula jeffreyi, impliquée dans la formation de biofilms benthiques, par des méthodes classiques d’analyse. L’utilisation d’une nouvelle méthode, la Chromatographie Gazeuse Inverse (CGI), a permis d’obtenir des résultats intéressants et relativement similaires, confirmant le caractère prometteur de la CGI pour l’étude des propriétés de surface des micro-organismes
The main goal of this thesis was to better understand the importance of Extracellular Polymeric Substances (EPS) in the structuring and formation of benthic biofilms; while considering a global conception of the ecological mechanisms involved in the functioning of intertidal mudflats. The development of the biochemical assays was done on the mucilage of the macroalgae Chaetomorpha aerea and allowed purifying a polysaccharide rich in galactose, showing a selective bactericidal activity against Staphylococcus aureus (ATCC 25923). Then, the biochemical and ecological studies concerning the EPS extracted from the local mudflat allowed studying their dynamic of production and composition in relation to environmental conditions. The presence of deoxy sugars and uronic acids in the bound EPS highlighted their important roles during the formation and the life of microphytobenthic biofilms. The last part of the work was used to characterize the acid/base of Lewis and hydrophilic/hydrophobic surface properties of the microalgae Navicula jeffreyi, involved in the formation of benthic biofilms, by using classical analysis methods. The use of a new method, named Inverse Gas Chromatography (IGC), allowed getting interesting and relatively similar results, confirming the potential of the method to study the surface properties of microorganisms

Orientadores: Maria Angela de Almeida Meireles, Marcia Ortiz Mayo Marques
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: A Bolívia oferece uma natureza diversificada. Vários exploradores botânicos se interessaram pelo estudo de plantas silvestres utilizadas pelos nativos de cada zona geográfica. Porem, ainda faltam estudos para a maioria das plantas silvestres com valor econômico, entre elas destaca-se a Khoa (Saturej~a boliviana Benth Briq), utilizada na medicina tradicional para ajudar na digestão dos alimentos e como planta aromática no preparo de comidas regionais. O presente trabalho tem por objetivo investigar as melhores condições de extração do óleo essencial de Khoa, mediante. destilação por arraste a vapor, solventes orgânicos e dióxido de carbono pressurizado. A khoa (Satureja boliviana Benth Briq) utilizada no presente trabalho foi coletada perto da cidade de La Paz Bolívia no mês de Janeiro de 1995, foi caracterizada morfológica e citologicamente. . A khoa é um arbusto nativo da Bolívia cuja altura varia entre 0,30 e 1,50 m, apresentando caules delgados, semilenhosos, folhas opostas e pequenas, contendo microgotas de óleo essencial na superfície superior e inferior, flores de cor branca, tamanho médio (2,5xl,2 mm). A epiderme superior apresenta tricomas pluricelulares glandulares, com a presença de óleo essencial. O caule apresenta epidermes esclerosadas e tecidos condutores para circulação de óleo essencial. A matéria prima foi caracterizada pela umidade (0,11 g água/ g de .massa seca), densidade (1,3 g/ml) e teor de voláteis totais (15,67%). A destilação por arraste a vapor foi estudada empregando-se um planejamento experimental combinado de dois e três níveis: tamanho de partícula (3 níveis), tempo de operação (3 níveis) e presença de água no extrator (2 níveis). Os fatores mais importantes no rendimento de extração foram o tamanho das partículas, (p=10-6) e tempo de operação (p=0,026). Recomenda-se extrair o óleo essencial das folhas de tamanho grande (Mesh -6 a +16), durante 30 min e sem água no extrator. O óleo essencial de khoa caracterizado pela densidade (0,926 g/ml) e o índice de refração (1,4835), apresenta atividade bactericida, testado em cultura de Escherichia coli, cuja dose letal 50% é 310,8I-Lg/ml. Os compostos principais identificados no extrato foram: pulegona, isomentona, rimol e 1,8- cineol. A extração de óleo essencial de khoa (Satureja boliviana Benth Briq) com etanol e isopropanol, foi realizada a frio, utilizando-se um extrator sólido/líquido com agitação magnética e temperatura controlada. O rendimento de extração foi estudado de acordo com planejamento fatorial fracionado com 2 níveis de 5 fatores: tipo de solvente (etanol e isopropanol); tamanho de partícula (pequena e média); relação solvente/sólido (3:1 e 6:1); temperatura de processo (20 e 30°C) e tempo de operação (30 e 60 min). Os fatores mais importantes foram a relação solvente/sôlido (p=4x10-4) e tamanho de partícula (p=0,014). Recomendando-se utilizar no processo de extração a relação 6:1 de solvente / sólido, tamanho pequeno de partículas (Mesh -35 a +65), temperatura ambiente (20 a 30°C) durante 30 min de extração, empregando-se etanol ou isopropanoI. Os compostos principais identificados no extrato foram: pulegona, isomentona e rimol. A extração com isopropanol produziu uma oleoresina, observando-se a presença de compostos mais pesados. Para o processo com dióxido de carbono, utilizou-se uma linha de extração com leito fixo, estudando-se a influência no rendimento de extração de 6 fatores, usando um planejamento experimental fracionado com dois níveis de variação: tamanho de partícula (pequeno e médio); temperatura de processo (16 e 21°C); pressão de processo (65 e 70kg/cm2); período estático (O e 1 h); vazão de dióxido de carbono (2,5 e 4,0 1/min) e co-solvente (sem e com etanol). Obteve-se os maiores rendimentos de extração, quando foi usado co-solvente(etanol) e uma vazão de 4,0 1/ min de dióxido de carbono. Os outros fatores, não influenciaram significativamente no rendimento de extração. As curvas de extração foram modeladas usando se o modelo empírico: E = Emax C*(Ks+C). A análise da composição química dos extratos mostrou que as condições operacionais influem na proporção relativa dos compostos. Finalmente, foi estabelecida a variação em função do tempo da composição do extrato, em termos dos compostos principais. A proporção relativa dos cimeno, 1,8- cineol, isomentona, pulegona e cariofileno diminuem em função do tempo de extração, enquanto que a do rimol aumenta
Abstract: Bolivia offers a diversified nature. Several Botanical explorers were interested in studying wild plants used by the natives of each geographical zone. Yet, the majority of the wild plant with economic value were not studied, among them can be mentioned "Khoa" (Saturo/a boliviana Benth Briq) used in the traditional (folk) medicine to help in the meal digestion and, also as an aromatic plant in the preparation of regional foods. The objective of the present work was to investigate the best conditions to obtain Khoa essencial oil using hydro-distillation, extraction with organic solvents and pressurized carbon dioxide. Khoa used in this work was collected dose to the city of La Paz in Bolivia, in January 1995 ànd was characterized morphologically and cytologically Khoa is a Bolivian native tree with a height varying between 0.30 to 1.50 m, presents thin shafts semi-woody, opposite and small leaves containing essential oil micro-drops on the superior and inferior surfaces, ,white flowers with an average size 2.5x12 mm, the superior epidermis has glandular pluri-cellular trichomes with essencial oil within them. The shaft has a sderotic epidermis and tis sue tubing for the essential oil circulation. The raw material was characterized by moisture (0.llg water/ g dry matter), density (1.3 g/m!) and total volatile content (15.67%). Hydro-distillation was studied using a factorial experimental design: partide size (3 levels), operational time (3 levels) and water content in the extractor (2 levels). For the response variable extraction yield the most important factors were partide size (p= 1 0.6) and operational time (p=0.026). Based on the results it is recommended to obtain the essential oil from large size leaves (Mesh -6 to+16), during 30 minutes and with no water in the extractor. Khoa essential oil which was characterized by the density (0.926g/m!) and the refraction index (1.4835) had bactericide activity evaluated with Escherichia coli culture, with a DL5o=310.8 µg/ mI. The main constituents identified in the extract were pulegone, isomenthone, thymol and 1,8-cineol. The extraction of khoa essential oil with ethanol or isopropanol was carried out using a solid/liquid extractor with magnetic stirring and controlled temperature. The effects of the following operational variables on the extraction yield were studied using a fractional factorial design: solvent type (ethanol or isopropanol); particle size (small or medium); solvent/solid ratio (3:1 or 6:1); process temperature (20 or 30°C) and operational time (30 or 60 min). The most important factors were the solvent/solid ratio (p= 0.0004) and particle size (p=0.014). Based on the results it is recommended to use a 6:1 solvent/ solid ratio, small particle size (Mesh -35 to +65), at room temperature (20 to 30°C) for 30 minutes, and using ethanol or isopropanol. The main compounds identified in the extract were pulegone, isomenthone and thymol. The isopropanol ex~action produced an oleoresin with heavier compounds. For the carbon dioxide process an extraction unit with a fixed bed extractor was used. A factorial experimental design with two levels was employed to study the influence on the extraction yield of the following factors: particle size (small or medium); process temperature (16 ar 21°C); process pressure (65 or 70kg/cm2); static period (O or 1 h); carbon dioxide flow rate (2.5 or 4.0 l/min) and co-solvent (with or without ethanol). The highest extraction yield was obtained using ethanol as co-solvent at a solvent flow rate of 4.0 l/min. The other variables did not significantly influence the extraction yield. The extraction curves were modeled using the following empirical model: E = Emax C*(Ks+C). The chemical composition analysis of the extracts showed that the operational conditions affected the relative proportion of the compounds. Finally, it was observed that the relative proportion of the p-cimene, 1,8-cineol, isomenthone, pulegone and caryophyllene decreased as a function of extraction time, while thymol increased
Doutorado
Engenharia de Alimentos
Doutor em Engenharia de Alimentos

Numerous ecological studies have used lipids to determine trophic pathways in aquatic systems, as fatty acid profiles provide time-integrated information on an organism’s assimilated diet. Many of these studies have, however, been based on sample collections with a limited temporal scale. The trophic ecology of pelagic systems has been studied intensively using fatty acid analyses, but very little work has been directed toward benthic communities, with the intertidal being especially neglected. The investigation of trophic pathways within rocky shore communities will help us to better understand system responses to environmental changes. The determination of long term temporal variation of the food web within a community could reveal the type, magnitude, duration and frequency of highly seasonal productivity. Changes in fatty acid profiles through time in primary consumers of intertidal rocky shores are poorly understood, but represent an important step towards a more comprehensive understanding of rocky shore food webs, compared with those derived from snapshot or short-term studies. The aim of this thesis was to clarify the temporal variability in the diets of rocky shore intertidal suspension-feeders (the brown mussels Perna perna and the Cape reef worm, Gunnarea gaimardi) and grazers (the Cape sea urchin Parencinus angulosus and the Goat-eye limpet, Cymbulus oculus) on the south east coast of South Africa using fatty acid profiles, and to investigate the effects of life style (e.g. feeding mode) and life cycle on temporal variations in tissue fatty acid profiles. I had three hypotheses: firstly, that suspension-feeders experience high levels of variability in their diets through time because water quality has the potential to change quickly and drastically, whereas grazers experience less variability in their diets over time since their food sources are more constant. Secondly, the reproductive cycles of the suspension-feeder P. perna and the grazer P. angulosus affect the fatty acid composition of their gonads, with temporal variations in lipid composition reflecting changes in reproduction investment. Thirdly, the total amount of energetic reserves available for reproduction are different for each gender (females allocate more energy to egg production than males allocate to gamete production). To address these aims, fatty acid profiles of suspension-feeders and grazers were investigated over a period of twelve months (from July 2010 to June 2011) at a single site on the south east coast of South Africa. The results showed high variability in the fatty acid composition of both the suspension-feeders strongly related with changes in their food source (suspended particulate material). Furthermore, similar temporal changes in fatty acid profiles of the two suspension-feeders were observed over time, reflecting their common diet and life style. There were some inter-specific differences in the suspension-feeders, likely originating from differences in their particle capturing mechanisms. Grazers showed less variability through time compared with the suspension-feeders, with the limpets being more consistent than the sea urchins. The temporal variability in the sea urchin diets may have resulted from the highly diverse and heterogeneous food sources available to them, whereas limpets may be more selective and have a limited range of diet items. Differences between the two grazer species may have arose from differences in their feeding strategies and intertidal zonation. The fatty acid compositions of gonad tissues in both P. perna and P. angulosus showed temporal variability strongly related to reproductive cycle. Differences in the fatty acid values between females and males were apparent, with females richer in total and polyunsaturated fatty acids than males. Spawning and gametogenesis influenced the variability of fatty acids through time in both species, suggesting the importance of considering the reproductive cycle when studying lipids in rocky shore species. Little evidence of lipid transfer between muscles and gonads was seen, suggesting the importance of direct lipid storage into the reproductive tissues. The influence of diet and life history of intertidal consumers on the temporal variability of their fatty acid compositions is important to understand, as it provides us with a better understanding of the functioning of rocky shore systems. There is an enormous potential for future research in this field of study.

碩士
國立中山大學
資訊工程學系研究所
107
Benthic organisms play a very important role both in scientific research and in aquaculture. However, it often takes a long time to observe or take the target organism out of its living environment to observe its status. The massive cost of labor is its main drawback. And in order to achieve automatic identification, it is also necessary to match the technology with flexibility to cope with various benthic organisms. In recent years, image processing technology has become more and more developed. In particular, the recently-popular deep learning technology can identify some of the objects that are less features. In a neural network model, after analyzing multiple neural layers, a set of predictive answers are obtained. Finally, minimize the error rate by training and continually correcting identified parameters. The neural network model must go through a lot of learning processes to achieve this effect, not all items have a large amount of training samples to make the model learn to the extent available. The data of benthic organisms is even more difficult to obtain. Therefore, this paper proposes Benthic Organisms Automatic Recognition System. The system provides the collection method of automatic labeling function, the deep network model with strong and fast computing speed, and finally the system also provides the final recognition result according to the user interface.

The International Commission on Radiological Protection (ICRP) has modeled twelve reference animal and plant (RAP) species using simple geometric shapes in Monte���Carlo (MCNP) based simulations. The focus has now shifted to creating voxel phantoms of each RAP to advance the understanding of radiation interactions in nonhuman biota. The work contained herein presents results for the voxel phantom of the Dungeness crab, Metacarcinus magister, the Sand Dab, Limanda limanda, and the brown seaweed, Fucus vesiculosus, and details a generalized framework for creating voxel phantoms of the other RAPs. Absorbed fractions (AFs) for all identified organs were calculated at several discrete initial energies: 0.01, 0.015, 0.02, 0.03, 0.05, 0.1, 0.2, 0.5, 1.0, 1.5, 2.0, and 4.0 MeV for photons and 0.1, 0.2, 0.4, 0.5, 0.7, 1.0, 1.5, 2.0 and 4.0 MeV for electrons. AFs were then tabulated for each organ as a source and target at each energy listed above. AFs whose error exceeded 5% are marked with an underline in the data tables; AFs whose error was higher than 10% are shown in the tabulated data as a dashed line. The AF���s were highly dependent on organ mass and geometry. For photons above 0.5 MeV and electrons above 0.2-0.4 MeV a nontrivial amount of energy escapes the source organ.
Graduation date: 2013

碩士
國立中山大學
海洋生物科技暨資源學系研究所
97
Kaohsiung Harbor used to be the third largest harbor of the world , and also the biggest one in Taiwan at present. Even though it’s not in the list of ten biggest harbors now, a lot of ship around the world comes frequently. There are also several shipyards and fishing ports in the area of Kaohsiung Harbor, it’s horrible that the harbor area is polluted by organotin compound pollutant. . Following are five major benthic organisms: Distorsio reticularis, Niotha conoidalis, Metapenaeopsis palmensis, Portunus argentatus and Portunus hastatoides. . Monobutyltin(MBT) is almost detected in the sediment of all the stations, and the concentration is between 5.4 and 17.9 ng /g wet wt as tin. Dibutyltin(DBT) is detected in the sediment of all the station, and the concentration is between 9.5 and 12.5 ng /g wet wt as tin. Tributyltin (TBT) is just detected at station D2 with the concentration of 8.7 ng /g wet wt as tin. The organotin in Distorsio reticularis, Niotha conoidalis, Metapenaeopsis palmensis, Portunus argentatus and Portunus hastatoides are obviously accumulated. In Distorsio reticularis, the concentration of TBT is between ND and 112.6 ng /g wet wt as tin. In Niotha conoidalis, the concentration of TBT is between 12.4 and 217.7 ng /g wet wt as tin, in Portunus argentatus, is between 3.0 and 3.4 and inPortunus hastatoides is between 5.5 and 92.1, in Metapenaeopsis palmensis, is between 3.7 and 37.0. In all station, monobutyltin is the main composition of butyltins; TBT concentration is almost less than 100 ng /g wet wt as tin. The concentration of butyltins in all the five major benthic organisms decreases with the increasing sample size. There wasn’t significant variation for organotin concentrations in Metapenaeopsis palmensis collected from each stationsand seasons. The concentration of Portunus argentatus and Portunus hastatoides is higher in April 2008 and January 2008 than in other months. According to many study, the content of organotins in sediment around coastal areas out of harbor is obviously less than other coastal areas of large-scale harbors (Lisbon, Sines, Sagres, Huelva, Cadiz and Trafalgar). The organotin contamination around coastal areas out of harbor is not serious. Base on estimation of amounts, distributions and contents of organotin in organisms, Portunus argentatus and Portunus hastatoides are better bethic organisms than Distorsio reticularis, Niotha conoidalis, and Metapenaeopsis palmensis in all the depth and area. The amount is also huge that Portunus argentatus and Portunus hastatoides are the best indicator organism for this area.

碩士
國立高雄師範大學
生物科技系
104
Leakage of explosives were commonly found in manufacture, dumpsites, military exercises, transportation and arsenals in military facilities. Thus, these will result in contamination of soil and groundwater and aquatic environment. The objective of this study was to use sediment testing intermittent renewal system to evaluate potential toxicity of explosives on to sediment. Terrestrial toxicity test of explosives was also established to evaluate potential inmpact onto terrestrial species. our target compounds including 2,4-DNT (2,4-dinirotoluene), TNT (trinitrotoluene), RDX (cyclotrimethylenetrinitramine) and HMX(octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) were studied to evaluate acute toxicity in the terrestrial, sediment and aquatic environment. Test species including Neocaridina shrimp (Neocaridina denticulata), amphipod (Hyalella azteca), carp (Carassius auratus), silkworm (Tubifex hattai), and earthworm (Eisenia fetida ) were used in acute toxicity test. Preparation of contaminated sediments and toxicity test methods were adopted from Organisation for Economic Cooperation and Development (OECD)Method 207. The results indicated that 2,4-DNT and TNT have higher toxicity which has revealed by low lethal concentration. On the other hand, HMX has relatively low toxicity. Low ecological risk were found when exposed to 2,4-DNT and TNT. It was found that 2,4-DNT at concentration of 5.13 mg/L, the aquatic species may be affected. TNT at concentration of 0.79 mg/L may cause ecological risk for 5 aquatic species in the ecosystem.

碩士
國立中山大學
海洋生物科技暨資源學系研究所
97
The port of Kaohsiung which was the third largest harbor in the world previously is still the biggest one in Taiwan at present. Because of shipping coming from all over the world persistently and there are several shipyards and fishing ports in harbor, the harbor area is seriously polluted by organotin compound. Nevertheless, it is not understood whether the pollution of organotin affect the marine ecosystem around coastal areas out of harbor. The first goal of this study concerns about organotin contamination and distribution of the sediments and major benthic organisms around coastal areas out of harbor. The second one is to find the adequate indicator organism which fits for organotin contamination. Five major benthic organisms including Distorsio reticularis, Niotha conoidalis, Metapenaeopsis palmensis, Portunus argentatus and Portunus hastatoides were collected and investigated in this study. The organotin concentration of sediments in all stations was not detected totally. The organotin accumulations in Metapenaeopsis palmensis, Portunus argentatus and Portunus hastatoide are not obvious. In Portunus argentatus and Portunus hastatoide, both the contents of tributyltin (TBT) were not detected. In Metapenaeopsis palmensis, the concentration of TBT is between ND∼3.4 ng/g as tin. In Distorsio reticularis and Niotha conoidalis, organotin is measured in all station; monobutyltin (MBT) is the main composition of butyltins; TBT is less than 10 ng/g as tin. The concentration of butyltins in Niotha conoidalis decreased with the increased wet weight. There was no significant variation for organotin concentrations in Niotha conoidalis collected from each stations and seasons. According to this study, the content of organotins in sediment around coastal areas out of harbor is obviously less than other coastal areas of large-scale harbors (Lisbon, Sines, Sagres, Huelva, Cadiz and Trafalgar). The organotin contamination around coastal areas out of harbor is not serious. Base on amounts, distributions and contents of organotin in organisms, Distorsio reticularis and Niotha conoidalis are better bethic indicator organisms than Metapenaeopsis palmensis, Portunus argentatus and Portunus hastatoides. Niotha conoidalis distributes over the depth less than 30 m, and therefore is a good indicator organism for this area. The facts that Distorsio reticularis distributes over the depth more than 30 m, suggest that it is a proper indicator organism for this area although lesser in population.

碩士
國立高雄師範大學
生物科技系
106
Sediments have a major role in ecosystem functioning but can also act as physical or chemical stressors. The importance of sediments as stressors will depend on site ecosystem attributes and the magnitude and preponderance of co-occurring stressors. Risk assessments and restoration strategies should better consider the role of chemical contamination in the context of multiple stressors. Methods for assessing site-specific ecological impairments resulting from the physical stress of excessive sediments are not highly developed. In contrast to aquatic toxicity testing where test protocols have been standardized, testing protocols for soils still lack harmonization. Biological assays have been developed by the Organization for Economic Co-operation and Development(OECD), the United States Environmental Protection Agency(U.S. EPA), and individual researchers for use in assessing soil toxicity related to earthworms(Perionyx excavatus), plants, and bacteria. The objective of this study was to propose ecotoxicological studies to provide systematic assessment to evaluate ecological response when assessing contaminated sediment and soils. Bioassays used for sediment quality assessment typically rely on static continuous exposure of a test organism to a contaminant or contaminated sediment. Ecotoxicity testing has been used in combination with contaminant and remediated soils and sediments in site assessments. Earthworm and benthic species including Japanese swamp shrimp(Neocaridina denticulata), sludge worm(Tubifex hattai), and amphipod(Hyalella azteca) were adopted for toxicity test. Acute toxicity tests were used to assess the toxicity of contaminated sediments and soils to organisms. copper, cadmium, lead, and trichloroethylene were selected as target contaminants. Results of acute toxicity indicated that copper posed highest toxicological effects onto earthworms in soil prepared in the laboratory. However, trichloroethylene posed highest toxicity onto earthworm in contaminated soil. Also it was found that trichloroethylene posed highest toxicity onto earthworm in subchronic toxicity tests(i.e., LC10=61.19 mg/kg). Cadmium posed highest toxic effects onto larvae. Lead posed highest toxic effect onto Japanese swamp shrimp in sediment test. Sludge worm(Tubifex hattai) and amphipod(Hyalella azteca) was sensitive to copper with LC50 of 15.47 mg/kg and 1.14mg/kg, respectively. Japanese swamp shrimp was most sensitive by cadmium in sediment with mixture of target contaminants. However, sludge worm(Tubifex hattai) was most sensitive to lead. Cadmium posed highest toxicological effects onto amphiod(Hyalella azteca). This study provided base-line toxicity information of aquatic species in contaminated sediments and toxicity information of terrestrial species in contaminated soils for ecological risk assessment, including the NOEC, LOEC, LC50 and EC50. Moreover to establish ecotoxicological test protocols of contaminated sediment and soils.

Urban streams are influenced by number of human activities. Diploma thesis discusses the impact of urban drainage (specifically storm water drains) on toxic metal concentrations, of, in one of Prague's minor creeks - Zátišský Creek. Zátišský Creek flows from the right side to the Vltava River. The creek is 3080 m long with a natural flow 1.9 m3 /s. The creek is affected by seven storm water drains and three rain settling tanks. The creek was monitored from April 2009 to June 2010 during this period six sampling campaign was conducted. The samples were collected from seven remote sampling points, located both upstream and downstream from the storm water drains and rain settling tanks. The impact of storm water drains was assessed based on monitoring of toxic metals content in different parts of the aquatic environments, samples of water, sediment and aquatic biota (benthic organisms and attached algae) were collected and analyzed. The sediment samples and organisms were dried by lyophilisation (freeze dry), and digested in a microwave oven using a solution of nitric acid and hydrogen peroxide. Metal concentrations were determined by Atomic Absorption Spectrometry utilizing instrument Solaar S. Overall nine metals were identified: cadmium, lead, nickel, chromium, copper, zinc, aluminum, manganese...

In Nova Scotia subtidal habitats, the invasive bryozoan Membranipora membranacea interacts with native bryozoan Electra pilosa on kelps, which offer high space availability but are highly dynamic, and on non-kelp algae, which provide low space but high stability. Settlers and colony cover of M. membranacea at various stages critical to its population dynamics, as well as relative abundance and encounter outcomes of M. membranacea and E. pilosa, were quantified on these substrates. I also examined the effects of various factors on growth rates of E. pilosa. For M. membranacea populations, the roles of kelp and non-kelp substrates varied intra- and inter-annually, as well as spatially. Membranipora membranacea was relatively more abundant on kelps than on Fucus, likely due to large colony size, faster growth, and strong overgrowth abilities. While kelps provide spatial resources for seasonal peaks in abundance of M. membranacea, non-kelp refuges can preserve local populations in time.

Hypoxia is frequently detected during summer in Corpus Christi Bay, Texas, and causes significant harm to benthic organism population and diversity. Hypoxia is associated with the density stratification in the Bay but the cause of stratification is uncertain. To support the study of hypoxia and stratification, a cyberinfrastructure based on the CUAHSI (Consortium of Universities for the Advancement of Hydrologic Science, Inc) Hydrologic Information System (HIS) is implemented. HIS unites the sensor networks in the Bay by providing a standard data language and protocol for transferring data. Thus hypoxia-related data from multiple sources can be compiled into a structured database. In Corpus Christi Bay, salinity data collected from many locations and times are synthesized into a three-dimensional space-time continuum using geostatistical methods. The three dimensions are the depth, the distance along a transect line, and time. The kriged salinity concentration in space and time illuminates the pattern of movement of a saline gravity current along the bottom of the Bay. The travel time of a gravity current in the Bay is estimated to be on the order of one week and the speed is on the order of 1 km per day. Statistical study of high-resolution wind data shows that the stratification pattern in the Bay is related to the occurrence of strong, southeasterly winds in the 5 days prior to the observation. This relationship supports the hypothesis that stratification is caused by the wind initiating hypersaline gravity currents which flow from Laguna Madre into Corpus Christi Bay. An empirical physical hypoxia model is created that tracks the fate and transport of the gravity currents. The model uses wind and water quality data from real-time sensors published by HIS to predict the extent and duration of hypoxic regions in the Bay. Comparison of model results with historical data from 2005 to 2008 shows that wind-driven gravity currents can explain the spatially heterogeneous patterns of hypoxic zones in Corpus Christi Bay.
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The purpose of this work was to describe the current status of benthic communities on the main stream of Elbe River and Ohře River and their tributaries affected and non-affected by biological invasions - especially by round goby (Neogobius melanostomus) and spiny - cheek crayfish (Faxonius limosus). Sampling for this research took place from April 2018 to August 2018, while morphiologic survey of waterbodies was done in November 2017. Two tributaries of the Elbe River (Milešovský brook and Ploučnice River) and one tributary of the Ohře River (Čepel) were selected for this research. Two 100 m long sections (lower stretch potentially affected by invaders and upper stretch as referential) were monitored at each tributary. At the same time a 100 m long main flow section was monitored near the mouth of the tributaries. The following parameters were monitored: morphology of the stream and basic physical and chemical parameters of water, zoobenthos community, crayfish occurrence, and fish community. The benthic communities of the upper streams were less affected by biological invasions. The biodiversity of the benthic communities in the upper sections was richer compared to the lower sections. The occurrence of the round goby seemed to be factor affecting benthic and fish communities at the sites concerned. It was an eudominant species in the Elbe section in Děčín and becoming dominant in the lower section of Ploučnice River.

Overall, around 15,000 pharmacologically active compounds have been isolated from marine species, many of which are structurally unique and absent in terrestrial organisms. Extremophiles are organisms that have developed specific adaptations that allow them to survive prohibitive conditions for humans. The purpose of this work is to combine these two aspects, investigating the associated microbial community with 2 types of filtering organisms, Arctic bivalve molluscs (Margaritifera margaritifera) (Fig.1) and Antarctic poriferous (Calyx arcuaria, Haliclona virens, Haliclona (Rhizoniera) dancoi, Haliclona rudis), to take advantage of potential developed by extremophiles, analyze the secondary metabolites produced and assess the presence of pharmacological properties. In specific, possible antiproliferative, antiparasitic and antimicrobial activities were been evaluated against, most common cancer cell lines, parasitics and pathogenic bacteria.