Littérature scientifique sur le sujet « Antarctic benthos »
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Articles de revues sur le sujet "Antarctic benthos"
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Taboada, Sergi, Luis Francisco García-Fernández, Santiago Bueno, Jennifer Vázquez, Carmen Cuevas et Conxita Avila. « Antitumoural activity in Antarctic and sub-Antarctic benthic organisms ». Antarctic Science 22, no 5 (19 juillet 2010) : 494–507. http://dx.doi.org/10.1017/s0954102010000416.
Texte intégralRésumé :
AbstractA prospecting search for antitumoural activity in polar benthic invertebrates was conducted on Antarctic and sub-Antarctic benthos in three different areas: Bouvet Island (sub-Antarctic), eastern Weddell Sea (Antarctica) and the South Shetland Islands (Antarctica). A total of 770 benthic invertebrate samples (corresponding to at least 290 different species) from 12 different phyla were assayed to establish their pharmacological potential against three human tumour cell lines (colorectal adenocarcinoma, lung carcinoma and breast adenocarcinoma). Bioassays resulted in 15 different species showing anticancer activity corresponding to five different phyla: Tunicata (5), Porifera (4), Cnidaria (3), Echinodermata (2) and Annelida (1). This appears to be the largest pharmacological study ever carried out in Antarctica and it shows very promising antitumoural activities in the Antarctic and sub-Antarctic benthos.
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Sahade, Ricardo, Cristian Lagger, Luciana Torre, Fernando Momo, Patrick Monien, Irene Schloss, David K. A. Barnes et al. « Climate change and glacier retreat drive shifts in an Antarctic benthic ecosystem ». Science Advances 1, no 10 (novembre 2015) : e1500050. http://dx.doi.org/10.1126/sciadv.1500050.
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The Antarctic Peninsula (AP) is one of the three places on Earth that registered the most intense warming in the last 50 years, almost five times the global mean. This warming has strongly affected the cryosphere, causing the largest ice-shelf collapses ever observed and the retreat of 87% of glaciers. Ecosystem responses, although increasingly predicted, have been mainly reported for pelagic systems. However, and despite most Antarctic species being benthic, responses in the Antarctic benthos have been detected in only a few species, and major effects at assemblage level are unknown. This is probably due to the scarcity of baselines against which to assess change. We performed repeat surveys of coastal benthos in 1994, 1998, and 2010, analyzing community structure and environmental variables at King George Island, Antarctica. We report a marked shift in an Antarctic benthic community that can be linked to ongoing climate change. However, rather than temperature as the primary factor, we highlight the resulting increased sediment runoff, triggered by glacier retreat, as the potential causal factor. The sudden shift from a “filter feeders–ascidian domination” to a “mixed assemblage” suggests that thresholds (for example, of tolerable sedimentation) and alternative equilibrium states, depending on the reversibility of the changes, could be possible traits of this ecosystem. Sedimentation processes will be increasing under the current scenario of glacier retreat, and attention needs to be paid to its effects along the AP.
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Barnes, David K. A., et Kathleen E. Conlan. « Disturbance, colonization and development of Antarctic benthic communities ». Philosophical Transactions of the Royal Society B : Biological Sciences 362, no 1477 (30 novembre 2006) : 11–38. http://dx.doi.org/10.1098/rstb.2006.1951.
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A decade has yielded much progress in understanding polar disturbance and community recovery—mainly through quantifying ice scour rates, other disturbance levels, larval abundance and diversity, colonization rates and response of benthos to predicted climate change. The continental shelf around Antarctica is clearly subject to massive disturbance, but remarkably across so many scales. In summer, millions of icebergs from sizes smaller than cars to larger than countries ground out and gouge the sea floor and crush the benthic communities there, while the highest wind speeds create the highest waves to pound the coast. In winter, the calm associated with the sea surface freezing creates the clearest marine water in the world. But in winter, an ice foot encases coastal life and anchor ice rips benthos from the sea floor. Over tens and hundreds of thousands of years, glaciations have done the same on continental scales—ice sheets have bulldozed the seabed and the zoobenthos to edge of shelves. We detail and rank modern disturbance levels (from most to least): ice; asteroid impacts; sediment instability; wind/wave action; pollution; UV irradiation; volcanism; trawling; non-indigenous species; freshwater inundation; and temperature stress. Benthic organisms have had to recolonize local scourings and continental shelves repeatedly, yet a decade of studies have demonstrated that they have (compared with lower latitudes) slow tempos of reproduction, colonization and growth. Despite massive disturbance levels and slow recolonization potential, the Antarctic shelf has a much richer fauna than would be expected for its area. Now, West Antarctica is among the fastest warming regions and its organisms face new rapid changes. In the next century, temperature stress and non-indigenous species will drastically rise to become dominant disturbances to the Antarctic life. Here, we describe the potential for benthic organisms to respond to disturbance, focusing particularly on what we know now that we did not a decade ago.
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Brey, T., C. Dahm, M. Gorny, M. Klages, M. Stiller et W. E. Arntz. « Do Antarctic benthic invertebrates show an extended level of eurybathy ? » Antarctic Science 8, no 1 (mars 1996) : 3–6. http://dx.doi.org/10.1017/s0954102096000028.
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Depth distribution data were compared for 172 European and 157 Antarctic benthic invertebrate species occurring in the respective shelf areas. Antarctic species showed significantly wider depth ranges in selected families of the groups Bivalvia, Gastropoda, Amphipoda and Decapoda. No differences were found in Polychaeta, Asteroidea and Ophiuroidea, where European species also showed comparatively wide bathymetric ranges. These extended levels of eurybathy in the Antarctic benthos may be interpreted either as an evolutionary adaptation or pre-adaptation to the oscillation of shelf ice extension during the Antarctic glacial-interglacial cycle.
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Menna, F., E. Nocerino, S. Malek, F. Remondino et S. Schiaparelli. « A COMBINED APPROACH FOR LONG-TERM MONITORING OF BENTHOS IN ANTARCTICA WITH UNDERWATER PHOTOGRAMMETRY AND IMAGE UNDERSTANDING ». International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2022 (30 mai 2022) : 935–43. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2022-935-2022.
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Abstract. Long-term monitoring projects are becoming more than ever crucial in assessing the effects of climate change on marine communities, especially in Antarctica, where these changes are expected to be particularly dramatic. Detailed studies of the Antarctic benthos are in fact particularly important for a better understanding of benthos dynamics and potential climate-driven shifts. Here, due to the extreme fragility of benthic communities, non-destructive techniques represent the best solution in long-term monitoring programs. In this paper we report new results from 2017, 2018, 2019 photogrammetric campaigns within the Italian National Antarctic Research Program (PNRA). A new protocol of data acquisition and multi-temporal processing that provides co-registered 3D point clouds between the three years without control points nor direct georeferencing methods is presented. This is achieved by adding a level of image understanding leveraging semantic segmentation with convolutional neural network (CNN) of the benthic features. Slow growing (estimated less than a mm per year) organisms, such as Corallinales (Rhodophyta algae), represent a natural stable pattern, leveraged to automatically orient in the same reference system the photogrammetric surveys of different epochs. This approach is also proved to be effective in improving the orientation of adjacent strips acquired within the same campaign. Within the paper an in depth analysis of the achieved results shows the effectiveness of the implemented procedure.
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Avila, Conxita, Xavier Buñuel, Francesc Carmona, Albert Cotado, Oriol Sacristán-Soriano et Carlos Angulo-Preckler. « Would Antarctic Marine Benthos Survive Alien Species Invasions ? What Chemical Ecology May Tell Us ». Marine Drugs 20, no 9 (24 août 2022) : 543. http://dx.doi.org/10.3390/md20090543.
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Many Antarctic marine benthic macroinvertebrates are chemically protected against predation by marine natural products of different types. Antarctic potential predators mostly include sea stars (macropredators) and amphipod crustaceans (micropredators) living in the same areas (sympatric). Recently, alien species (allopatric) have been reported to reach the Antarctic coasts, while deep-water crabs are suggested to be more often present in shallower waters. We decided to investigate the effect of the chemical defenses of 29 representative Antarctic marine benthic macroinvertebrates from seven different phyla against predation by using non-native allopatric generalist predators as a proxy for potential alien species. The Antarctic species tested included 14 Porifera, two Cnidaria, two Annelida, one Nemertea, two Bryozooa, three Echinodermata, and five Chordata (Tunicata). Most of these Antarctic marine benthic macroinvertebrates were chemically protected against an allopatric generalist amphipod but not against an allopatric generalist crab from temperate waters. Therefore, both a possible recolonization of large crabs from deep waters or an invasion of non-native generalist crab species could potentially alter the fundamental nature of these communities forever since chemical defenses would not be effective against them. This, together with the increasing temperatures that elevate the probability of alien species surviving, is a huge threat to Antarctic marine benthos.
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Post, Alexandra L., Philip E. O’Brien, Robin J. Beaman, Martin J. Riddle et Laura De Santis. « Physical controls on deep water coral communities on the George V Land slope, East Antarctica ». Antarctic Science 22, no 4 (26 mars 2010) : 371–78. http://dx.doi.org/10.1017/s0954102010000180.
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AbstractDense coral-sponge communities on the upper continental slope at 570–950 m off George V Land, East Antarctica have been identified as Vulnerable Marine Ecosystems. The challenge is now to understand their probable distribution on other parts of the Antarctic margin. We propose three main factors governing their distribution on the George V margin: 1) their depth in relation to iceberg scouring, 2) the flow of organic-rich bottom waters, and 3) their location at the head of shelf cutting canyons. Icebergs scour to 500 m in this region and the lack of such disturbance is a probable factor allowing the growth of rich benthic ecosystems. In addition, the richest communities are found in the heads of canyons which receive descending plumes of Antarctic Bottom Water formed on the George V shelf, which could entrain abundant food for the benthos. The canyons harbouring rich benthos are also those that cut the shelf break. Such canyons are known sites of high productivity in other areas due to strong current flow and increased mixing with shelf waters, and the abrupt, complex topography. These proposed mechanisms provide a framework for the identification of areas where there is a higher likelihood of encountering these Vulnerable Marine Ecosystems.
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Schram, Julie B., Margaret O. Amsler, Aaron W. E. Galloway, Charles D. Amsler et James B. McClintock. « Fatty acid trophic transfer of Antarctic algae to a sympatric amphipod consumer ». Antarctic Science 31, no 6 (22 octobre 2019) : 315–16. http://dx.doi.org/10.1017/s0954102019000397.
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The shallow benthos along the western Antarctic Peninsula supports brown macroalgal forests with dense amphipod assemblages, commonly including Gondogeneia antarctica (Amsler et al. 2014). Gondogeneia antarctica and most other amphipods are chemically deterred from consuming the macroalgae (Amsler et al. 2014). They primarily consume diatoms, other microalgae, filamentous macroalgae and a few undefended macroalgal species, including Palmaria decipiens (Aumack et al. 2017). Although unpalatable when alive, G. antarctica and other amphipods will consume the chemically defended brown algae Himantothallus grandifolius and Desmarestia anceps within a few weeks of death (Amsler et al. 2014).
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Gutt, Julian, et Thomas Schickan. « Epibiotic relationships in the Antarctic benthos ». Antarctic Science 10, no 4 (décembre 1998) : 398–405. http://dx.doi.org/10.1017/s0954102098000480.
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On the high Antarctic shelf, 374 different epibiotic relationships of the megafauna were photographically registered and statistically analysed. These comprised 47 different epibiotic and 96 substratum taxa and had obvious differences in abundance and presence in three different benthic assemblages. Six abundant obligatory relationships in which the epibiont occurred almost exclusively on one type of substratum had highly specialized epibionts. For an additional eight relationships, a statistical test revealed that the epibionts preferred specific living and elevated mineral substrata. Most of these relationships are interpreted as commensalism (sensu Odum) in which the suspension feeding epibiont profits from the elevated position. Here it has better access to food compared with life on the sediment. The evolution of a rich and mainly sessile epifauna on parts of the high Antarctic shelves and the successful development of epibiotic behaviour in other species are suggested as a major reason for the high species richness in the benthic fauna. The results provide evidence that the Antarctic megabenthos is more biologically accommodated than physically controlled.
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García-Alvarez, O., V. Urgorri et L. von Salvini-Plawen. « Two new species of Dorymenia (Mollusca : Solenogastres : Proneomeniidae) from the South Shetland Islands (Antarctica) ». Journal of the Marine Biological Association of the United Kingdom 80, no 5 (octobre 2000) : 835–42. http://dx.doi.org/10.1017/s0025315400002812.
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This paper describes two new species from the genus Dorymenia (Mollusca: Solenogastres: Proneomeniidae): D. hesperidesi sp. nov. and D. menchuescribanae sp. nov., collected during the Spanish oceanographic expeditions for the study of Antarctic benthos, BENTART'94 and BENTART'95, carried out in the area of the Livingston Island (South Shetland Islands, Antarctica). A comparative study of main specific characteristics of species belonging to the genus Dorymenia found off the South Shetland Islands and in the Bransfield Strait (Antarctica), is also included.
Thèses sur le sujet "Antarctic benthos"
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PIAZZA, PAOLA. « Analysis of Antarctic benthos dynamics and spatial patterns based on non-destructive techniques and image analysis : development of an integrated monitoring toolkit and general protocols ». Doctoral thesis, Università di Siena, 2019. http://hdl.handle.net/11365/1074688.
Texte intégralRésumé :
Introduction- First chapter introduces the Antarctic coastal marine environments, as part of the intriguing and challenging “puzzle” that scientific community is committed to resolve, represented by Antarctica and its changes. A brief glimpse on two of the main drivers influencing benthic communities dwelling in these areas, the sea-ice and the substrate, is given, with a special eye on the unresolved aspects of their influence on marine organisms and on the effect of their variations. Some of the major challenges of scientific researches in such extreme and fragile environment is highlighted together with an overview on ongoing and proposed strategies of the Scientific Committee on Antarctic Research (SCAR). Especially focusing on monitoring perspective, the essential requirement of the establishment of permanent sites and of specially protected areas is discussed. Later on, an overview on the study site and its inhabiting key species is presented. Recent advances in underwater technologies confer the opportunity to overcome previous technical limitations and to improve our capacity of investigation in similar areas. Between emerging techniques, non-destructive image-based ones are introduced in their theoretical aspects. Another pivotal aspect of monitoring is the strategy of sampling, one of the major issues on which relies the reliability of a monitoring project. Preliminary considerations on the relevance of choice of the best sampling design are described.
Materials and Methods- Second chapter describes the methodologies used to collect, elaborate and analyse data obtained from images. Firstly, field operations are described, corresponding to well-established protocol of nondestructive image-based SCUBA-operated sampling on shallow rocky bottoms. A particular attention is provided to the use made of sampled materials during the in-silico procedures. This is a newness element of this project, providing one of the first examples of application of some emerging image-based techniques in Antarctica. The informative potential that archived and new SCUBA-operated videos are able to store up about epifaunal communities composition and structure has been exploited by applying photogrammetric reconstruction and measurements. Due to the dated format of older videos, a procedure of adaptation to new applications was needed. In order to better explain these steps, a brief and simply panoramic on some major features of, as defined, ‘historical’ videos is given. Thanks to the proposed in-silico procedures, it has been possible to describe three-dimensional features of seafloor and dwelling organisms, also from videos not specifically meant for this purpose.
Later in the chapter, it is shown how spatial information about specimens distribution has been obtained thanks to a variety of GIS tools. Finally, it is supplied a summary of the statistical analyses used to the multiple aims of: i) exploring data, ii) describing macrobenthic populations and their spatial distribution, iii) deriving best sampling design for key species, iv) producing comparisons across years (thanks to two temporal repetitions) and sites.
Results- Third chapter reports the main results deriving from the different ‘fields of study’ of the research, including: i) a first section, specifically focusing on the photogrammetric output, with a special eye on the issues related to the use of ‘historical’ materials, as the used video samples were defined; and ii) a second, more ecological, section, reporting the results from counting procedures and spatial statistical analyses. The taxonomical composition of the megabenthic community is described: extendedly, in form of list of taxa that was
possible to distinguish and eventually recognize at the lower taxonomical level as possible; and synthetically, by the estimation of biodiversity indices. The small-scale spatial pattern analysis is, then, reported, highlighting the distribution and neighbour estimates of different taxa. Sampling strategy has different outcomes if applied to organisms with different distributions and, thus, when it is advisable to preventively study these spatial aspects. In our case, statistical analyses on sampling simulation suggest specific combinations of sample size and sampling scheme for the main keyspecies analysed. Finally, the results of the trial linear regression model between the distribution of the sea urchin Sterechinus neumayeri (Meissner, 1900) and of the encrusting algae Corallinales are reported, confirming the need of a major number of covariates in order to understand distributional pattern shaping factors.
Discussion- The final outcomes of the study are reviewed, according to the original aims and with the major issues of the research. The interpretation of some of the results is particularly investigated. The future perspectives are also mentioned, in many of the possible fields of improvement.
Conclusions- Due to the overall value of the proposed methodological approach and of the results of the study, they are presented as contibution to the definition of a standardized protocol of monitoring techniques for the Antarctic benthos, in the perspective of a shared international collaboration.
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Allan, Elizabeth Louise. « Trophodynamics of the benthic and hyperbenthic communities inhabiting the Sub-Antarctic Prince Edward Islands : stable isotope and fatty acid signatures ». Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1006350.
Texte intégralRésumé :
The aim of this study was to investigate spatial changes in the trophic and energy pathways of the benthic community in the shallow shelf waters of the sub-Antarctic Prince Edward Islands (PEI). A combination of stable isotope and fatty acid analyses were used to provide a time-integrated view of the assimilated feeding history of selected components of the PEI benthic community. This study forms part of the larger project entitled “Variability in the Southern Ocean ecosystems” and is a contribution to the South African National Antarctic Programme (SANAP). During austral autumn 2009, benthic specimens were collected from 10 stations (from depths of 70 to 295 m) in different regions around the PEI: inter-island shelf (upstream, between and downstream of the islands) and nearshore. Historical data were combined with new data collected during 2009 to assess the long-term trends in the feeding ecology of the benthos in the region of the islands. The stable isotope and fatty acid signatures of the benthic suspension- and deposit-feeding organisms generated during this study suggested that these two communities incorporated both phytoplankton and kelp in their diets. Stable isotope, and to a lesser extent fatty acid signatures, indicated that kelp contributed more to the diets of those organisms in close proximity to the kelp beds (nearshore stations) than those from the inter-island region. Overall, however, pelagic phytoplankton was the dominant food source in the diets of all organisms, even for those living near the kelp beds. Notable exceptions were the sponges and bryozoans, in which kelp and phytoplankton contributed similar proportions to their diets, most likely resulting from a size restricted feeding mode. There were, therefore, no distinct spatial differences in the importance of the various food sources. However, fatty acid compositional data indicated increased food quality between and within the lee of the islands compared to upstream. The organisms collected upstream of the PEI had substantially lower quantities of total fatty acids (TFAs) than organisms of the same species collected from nearshore, open shelf or downstream stations. The increased food quality between and within the lee of the islands was likely a result of the “island mass effect”, which reflects increased phytoplankton concentrations at the PEI. The fatty acid profiles of hyperbenthic shrimp Nauticaris marionis, a key species in the PEI ecosystem, revealed no distinct ontogenetic or spatial patterns. This result is in contrast to the stable isotope analyses, which detected both spatial and ontogenetic differences in the diet of the shrimp. Nearshore shrimp were more ₁₃C-enriched than those from the inter-island region, suggesting increased kelp entering the food web within these regions. In addition, the shrimps demonstrated enrichment in δ₁₃C and δ₁₅N signatures with an increase in size, resulting in a relatively distinct separation of size classes, thus reflecting niche separation through their diets. The fatty acid profiles revealed that the shrimp all contained large proportions of polyunsaturated fatty acids (PUFAs) and essential fatty acids (EFAs), indicating that the quality of food consumed was similar among size class and region despite the niche separation and variation in carbon sources utilised. In addition, diatom and dinoflagellate fatty acids (20:5ω3 and 22:6ω3, respectively) occurred in the highest proportions in N. marionis, highlighting the importance of phytoplankton (indirectly) in their diet. These results represent strong evidence that phytoplankton is an importance food source in the PEI ecosystem. The temporal investigation of isotope signatures in the benthos at the PEI indicated that N. marionis demonstrated an overall depletion in δ₁₃C signatures over the period of 1984 to 2009 (nearshore: -2.55 ‰, inter-island: -2.32 ‰). Overall, the benthic community showed similar depletions in δ13C signatures (from -1.96 to -4.70 ‰), suggesting that shifts have occurred in the carbon signatures at the base of the food web. The depletion in δ₁₃C signatures of the benthos at the PEI most likely reflects increased contributions of smaller slow growing phytoplankton cells (more depleted signatures than large fast growing cells) in the diets of these organisms over time. These diet shifts, in turn, suggest a decrease in productivity has occurred at the islands, likely due to a decreased frequency and intensity of the “island mass effect”. Decreased phytoplankton productivity at the PEI likely results from the southward shift in the average position of the sub-Antarctic Front (SAF), most likely in response to climate change, which in turn promotes flow-through conditions rather than retention at the PEI.
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Angulo, Preckler Carlos. « Biodiversity and Chemical Interactions in Antarctic Benthic Communities of Deception Island (South Shetland Islands) = Biodiversidad e Interacciones Químicas en las comunidades bentónicas Antárticas en Isla Decepción ». Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/385350.
Texte intégralRésumé :
This Thesis covers two different topics in Antarctic marine benthic invertebrates.
The two main goals are:
1) to improve the knowledge of the biodiversity of the shallow water benthic communities inside Deception Island (South Shetland Islands, Antarctica), and
2) to establish the chemical ecology of selected Antarctic organisms, by studying the antifouling and antimicrobial activity of their organic extracts.
Deception Island is an active volcano on the southwestern end of the South Shetland Island chain. This island chain parallels the northeastern curvature of the Antarctic Peninsula, but is separated from the Antarctic continent by the narrow Bransfield Strait. Volcanic activity is believed to be the key environmental component that controls epibenthic and infaunal invertebrate populations in Port Foster. Compared to nearby islands, Deception Island is clearly defaunate at depth, and since the last eruption in 1970, has been considerably recolonized. However, many taxa are still very poorly represented and the colonizer species are mainly those with planktotrophic larvae. Interestingly, the soft-bottom benthos communities of the shallowest zone of Port Foster has been barely and poorly explored yet. A complete study of the benthic invertebrate shallow community at Deception Island was conducted, looking for a comprehensive view of this singular spot working at different trophic levels. Shallow-water sediment at Deception Island is inhabited mostly by opportunistic, motile species, living under the influence of serious and long-lasting disturbances, related more to high sedimentation rates within the bay and the absent of hard substrata, than with the ice-scouring or anchor-ice disturbances (mostly absent inside the caldera, but common elsewhere in Antarctica). The trophic relationship between the water and benthic community has been described in four stages; (i) particulate matter is suspended from the seafloor into the water column; (ii) nutrients stimulate bacterial and phytoplankton production, which stimulates zooplankton production; (iii) large suspended particles provide food for planktonic and benthic grazers; and (iv) organisms no consumed sink to the seafloor to be utilized by benthic community. These nutrients would be transmitted to bacterial communities, known to use this abundant material over the year in some sites of the island. This microbial biomass could then be transmitted to the meiofauna, trophic level showing also high densities in Port Foster. Furthermore, Port Foster receives much runoff during the austral summer, and may serve as a “nutrient trap”, thus influencing the meiofaunal organisms. All these, together with the microbial communities, could be behind the high macrofaunal densities observed here. Finally, all these trophic compartments would then be supporting the remarkable density of megafaunal organisms at Port Foster.
Antarctic benthos is dominated by biological interactions, and it is expected that many marine invertebrates use chemicals as means of defense from predators, pathogens or preventing overgrowth. Natural products (also called secondary metabolites) are chemicals produced by organisms, which regulate the biology, co-existence, and co-evolution of the species without participating directly in their primary metabolism. The role of these natural products play in the Antarctic benthic communities is one of the main subjects of investigation in the present dissertation through an experimental contribution in the antimicrobial and antifouling field using chemical crude extracts from Antarctic benthic organisms. Marine secondary metabolites may play a role as deterrents against pathogenic microorganisms, fouling organisms, predators and/or competitors. Benthic marine organisms, under intense pressure for space, light and food, have developed a wide range of defensive mechanisms ranging from behavioral to physical and chemical strategies. Competition for space is a remarkable ecological force, comparable to predation that produce a strong selective pressure on benthic invertebrates. Some invertebrates, thus, possess antimicrobial compounds to reduce surface bacterial growth. The ubiquity of fouling organisms in the marine environment and the negative consequences of fouling are likely strong evolutionary pressures for marine organisms to develop defenses to protect their surface from fouling. In summary, marine invertebrates can survive in the highly competitive and hostile environments, mainly relying on their chemical defensive system by accumulating a series of defensive chemicals in their bodies or releasing the compounds to their surroundings.Isla Decepción es un volcán activo en el extremo suroeste de la cadena de islas Shetland del Sur. Esta cadena de islas discurre paralela a la curvatura noreste de la Península Antártica, pero está separada del continente antártico por el estrecho de Bransfield. Se cree que la actividad volcánica es el componente ambiental clave que controla las poblaciones de invertebrados epibentónicos e infaunales en Puerto Foster. En comparación con las islas cercanas, Isla Decepción está claramente depauperada en profundidad, y desde la última erupción en 1970, sus fondos han sido recolonizados progresivamente. Sin embargo, muchos taxones están poco representados y las especies colonizadoras son principalmente aquellas que tienen larvas planctotróficas. Curiosamente, las comunidades bentónicas de fondos blandos de la zona más somera de Puerto Foster apenas han sido estudiadas. En un contexto en que la Península Antártica está experimentando una de las tasas más rápidas de cambio climático regional en la Tierra, Isla Decepción se presenta como una buena oportunidad de trabajar con escenarios previsibles para las comunidades bentónicas antárticas costeras. Se ha realizado un estudio completo de la comunidad bentónica de invertebrados en aguas poco profundas de Isla Decepción, en busca de una visión integrada de este paraje singular estudiando diferentes niveles tróficos. El bentos antártico está dominado por interacciones biológicas, y es previsible que muchos invertebrados marinos utilicen productos químicos como medio de defensa contra los depredadores, contra patógenos o para evitar el recubrimiento (antifouling). El papel que estos productos naturales desempeñan en las comunidades bentónicas antárticas es uno de los principales temas de investigación en la presente tesis a través de una contribución experimental en el campo de los antimicrobianos y del antifouling utilizando extractos crudos de organismos bentónicos antárticos. Los invertebrados marinos pueden sobrevivir en entornos altamente competitivos y hostiles, confiando principalmente en su sistema defensivo químico mediante la acumulación de una serie de sustancias químicas defensivas en sus cuerpos o liberando los compuestos a su entorno.
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Figuerola, Balañá Blanca. « Biodiversity and Chemical ecology in Antarctic bryozoans = Biodiversitat i ecologia química de briozous antàrtics ». Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/129165.
Texte intégralRésumé :
The current thesis covers two important and poorly known aspects of Antarctic bryozoans: biodiversity and chemical ecology. The comparative analyses of diversity carried out here (Chapters 1 and 2) between Antarctica and the last separated fragments of Gondwana support the hypothesis of the sequential separation of Gondwana. We discuss that the high number of species from the Argentine Patagonian (AP) region shared with Antarctica found in our study question the real extent of Antarctic isolation for cheilostome bryozoans. The presence of shared common bryozoan species between these two regions may also be explained by the free migration of marine organisms in and out of the Polar Front, via the deep abyssal plains and the potential passive northwards transport of larvae (or perhaps even adults) to considerable distances, via the branch of the Antarctic Circumpolar Current (ACC) flowing northward along the continental shelf of Argentina, the Falkland/Malvinas Current. The role of the Scotia Arc and other dispersal pathways, like eddies of ACC, and human dispersal mechanisms, may increase the bryozoan connection found between the Antarctica and the AP region. Also, our studies (Chapters 1 and 2) are among the first characterizations of the bryozoan communities, mainly at the slope, from the AP region, and from the Southern Ocean (SO), specially the Weddell Sea. The bathymetric distribution from the AP region and the SO found in our studies fits well with the limits of the continental shelf, the slope and the deep sea. Interestingly, our research also shows an expansion in the known distribution of diverse bryozoan species from the AP region and the SO. Our results stress the importance of taxonomical studies in these scarcely explored regions, reporting a high number of new genera and species, and new records too. Among the new species found in our study, a bryozoan of the genus of Reteporella characterized by rare giant spherical avicularia is described in Chapter 3, leading us to discuss which are the potential roles of the avicularia. Since the studied bryozoan communities, below areas affected by local disturbances (iceberg scours and anchor ice), are mainly subject to biotic factors such as competence and predation, the evolution has favoured the development of chemical mechanisms in benthic organisms, which have also been investigated here (Chapters 4 and 5). Our studies are among the first reports on chemical ecology of Antarctic bryozoans. In order to study these chemical interactions, new adapted protocols were designed using sympatric and abundant predators. Our findings demonstrate the importance of diverse chemical ecology mechanisms against competence and predation in Antarctic bryozoans. Most bryozoan species tested here display cytotoxicity and/or repellent activity against the sea urchin Sterechinus neumayeri and the amphipod Cheirimedon femoratus, respectively (Chapter 4). In Chapter 5, our results demonstrate that bryozoans seem to be readily defended against at least one of the two abundant predators, Odontaster validus and C. femoratus. The intra- and interspecific variability in bioactivity suggest an adaptive response to diverse abiotic and biotic factors, presence of microorganisms and/or genetic variability. The general trend in our study indicates the presence of a combination of both chemical and physical defensive mechanisms in most bryozoan species, suggesting complementary traits. In general, these results lead to the conclusion that this phylum is very active with extended repellent activities.Aquesta tesi cobreix dos aspectes importants i poc coneguts dels briozous antàrtics: la biodiversitat i l'ecologia química. L'anàlisi comparatiu de diversitat realitzat aquí (Capítol 1 i 2) entre l'Antàrtida i altres zones geogràficament properes recolzen la hipòtesi de la separació seqüencial de Gondwana. Es discuteix que l'elevat nombre d'espècies de la regió de la Patagònia argentina (PA) compartides amb l'Antàrtida qüestiona el grau real d'aïllament de l'Antàrtida en briozous queilostòmats. Els nostres estudis (Capítols 1 i 2) són també una de les primeres caracteritzacions de les comunitats de briozous, principalment del talús, de la regió de la PA, i de l' Oceà Austral, especialment el Mar de Weddell. Els nostres resultats remarquen la importància dels estudis taxonòmics en aquestes regions escassament explorades, incloent un gran nombre de nous gèneres i espècies, i noves cites. Entre les noves espècies trobades en el nostre estudi, es descriu un briozou del gènere Reteporella caracteritzat per una rara aviculària esfèrica i gegant, portant-nos a reconsiderar quines són les possibles funcions de l'aviculària (Capítol 3). Com les comunitats estudiades de briozous, per sota de les zones afectades per pertorbacions locals (erosió per icebergs), estan subjectes principalment a factors biòtics com la competència i la depredació, l'evolució ha afavorit el desenvolupament de mecanismes químics de protecció (Capítols 4 i 5). Els nostres estudis són dels primers en ecologia química de briozous antàrtics. Els nostres resultats demostren la importància de diversos mecanismes d'ecologia química contra la competència i la depredació en briozous antàrtics. La majoria de les espècies de briozous mostraven activitat citotòxica i/o repel•lent contra l'eriçó de mar Sterechinus neumayeri i l'amfípode Cheirimedon femoratus, respectivament (Capítol 4). En el capítol 5, totes les espècies de briozous estudiats mostraven activitat de repel•lència alimentària contra almenys un dels dos depredadors abundants considerats, l'estrella de mar Odontaster validus i l'amfípode Cheirimedon femoratus. La tendència general en el nostre estudi indica la possessió d'una combinació de mecanismes físics i químics en la majoria de les espècies, fet que suggereix estratègies complementàries.
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DELL'ACQUA, OMBRETTA. « Response to climate change in Antarctic benthos - Environmental change in Antarctic marine ecosystem : study of long term observations and ocean acidification experiments to better understand the destiny of three key benthic species in the Terra Nova Bay littoral (Ross Sea) : Adamussium colbecki, Sterechinus neumayeri and Odontaster validus ». Doctoral thesis, Università degli studi di Genova, 2018. http://hdl.handle.net/11567/929157.
Texte intégralRésumé :
Climate changes effects include ocean acidification and, possibly, the alteration of frequency and magnitude of climate events, such as El Niño. All environmental global changes are supposed to be a major threat to ecosystem, both terrestrial and marine. Despite the amazing bulk of literature on these last, few efforts have been devoted to polar regions, which are actually likely to be the most fragile environments on the Earth. In this work we want to elucidate the response, to environmental modifications, of three Antarctic benthic macroinvertebrates: the scallop Adamussium colbecki, the sea urchin Sterechinus neumayeri and the sea star Odontaster validus, inhabiting the littoral area of Terra Nova Bay (Ross Sea, Victoria Land). Using long term series, we investigated potential correlation between A. colbecki recruitment and environmental variables (sea ice cover duration and El Niño events), reporting that A. colbecki recruitment is not affected by these variables. We also performed a manipulative experiment in the Mario Zucchelli Station to understand the effects of three pH levels (8.16, 7.8 and 7.6) on the three species, investigating the response of hard tissues and of the reproductive system. Results show that S. neumayeri spines are affected by low pH only at nanoscale and only in hardness property, while the shell of A. colbecki is not altered at all. As far as reproductive system, we found a significant effect in the gonado-somatic index and on stage development of A. colbecki, in addition to some damages in the gonad tissue, although not statistically significant. S. neumayeri shows the same disrupt tissue all over ovary and testes, although differences from the control are not statistically significant. Conversely, O. validus does not show any effect of low pH exposure at all. Further investigations are necessary to understand the energy costs of maintenance of the polar organisms and its potential consequence on individual life history and, thus, populations dynamic.
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Ambroso, Stefano. « Distribution patterns and abundance of Antarctic pristine benthic communities ». Doctoral thesis, Universitat Politècnica de Catalunya, 2021. http://hdl.handle.net/10803/671472.
Texte intégralRésumé :
Knowledge of the abundance, distribution patterns, and population ecology of antarctic benthic biodiversity have increased considerably during the last decades. Antarctic marine benthic biodiversity has been sampled primarily in areas close to research stations and mainly at shallow depths since more than 100 years using a range of sampling methods, including benthic sleds or trawls and grabs each of which targets a particular community or habitat. Recent technological advances and increased availability of remotely operated vehicles (ROVs), manned submersibles, and video equipped towed gears have significantly increased accessibility to mid and outer continental shelves, continental slopes, submarine canyons and seamounts, thus allowing the direct observation and quantitative study of megabenthic assemblages wthout any impact on the benthic community.
Due to the high cost and logistics of these benthic sampling, particularly in Antarctica, studies are often limited to only one biological sampling method. Results of biodiversity studies are used for a range of purposes, including taxonomy, trophic ecology, growth rates, reproductive ecology, environmental impact assessments, and predictive modelling, all of which underpin appropriate marine resource management. However, the generality of marine biodiversity patterns identified among different sampling methods is unknown.
This is one of the resons why more comparative studies are necessary to better understand the ecosystem patterns and processes in antactic regions in a context of climate change scenario.
Major regions of the Antarctic shelf appear to be undergoing rapid climate change, such as warming on the Antarctic Peninsula in the past few decades. Such climate change will affect benthic ecosystems through changes in benthic-pelagic coupling. For these porpouse this tesis pretend to generally understand the distribution and the eocological paper that benthic organisms have on the benthic ecosystem of the antarctic continental shelf. This thesis includes for chapters
In the first chapter we investigate ophiuroid assemblages in terms of the distribution and diversity patterns at three different environmental regimes and depths in the Antarctic Peninsula. In the second chapter we assessed the health status of Antarctic gorgonian assemblages in a pristine and remote area in the southernmost part of the Weddell Sea continental shelf. In the third chapter we compared the performance of two sampling gears by assessing quantitative data on the continental shelf of three oceanographically very distinct regions in Antarctic Peninsula. Finally in the fourth chapter we tried to understand the way in which a gorgonian population affects the diversity of the surrounding megafaunal species, by characterizing gorgonian assemblages dwelling on two very contrasting continental shelves.El conocimiento de la abundancia, los patrones de distribución y la ecología de población de la biodiversidad bentónica antártica ha aumentado considerablemente durante las últimas décadas. La biodiversidad bentónica marina antártica se ha muestreado principalmente en áreas cercanas a las estaciones de investigación y principalmente a poca profundidad desde hace más de 100 años utilizando una variedad de métodos de muestreo, incluidos trineos o redes de arrastre bentónicos, cada uno de los cuales se dirige a una comunidad o hábitat en particular. Los recientes avances tecnológicos y una mayor disponibilidad de vehículos operados a distancia (ROV), sumergibles tripulados y aparatos de muestreo equipados con videocámara han aumentado significativamente la accesibilidad a las plataformas continentales, taludes continentales, cañones submarinos y montañas submarinas, lo que permite la observación directa y el estudio cuantitativo de comunidades megabentónicas sin ningún impacto en la comunidad misma. Debido al alto coste y la compleja logística de estos muestreos, particularmente en la Antártida, los estudios que se generan a menudo se limitan a un solo método de muestreo biológico. Los resultados de los estudios de biodiversidad se utilizan para una variedad de propósitos, que incluyen taxonomía, ecología trófica, tasas de crecimiento, ecología reproductiva, evaluaciones de impacto ambiental y modelos predictivos, todos los cuales sustentan la gestión adecuada de los recursos marinos. Sin embargo, se desconoce la generalidad de los patrones de biodiversidad marina que se pueden identificar entre los diferentes métodos de muestreo. Esta es una de las razones por las que se necesitan más estudios comparativos para comprender mejor los patrones y procesos de los ecosistemas en las regiones antárticas en un contexto de escenario de cambio climático. Las principales regiones de la plataforma antártica parecen estar experimentando un cambio climático rápido, como el calentamiento en la Península Antártica en las últimas décadas. Dicho cambio climático afectará a los ecosistemas bentónicos a través de cambios en el acoplamiento bento-pelágico. Para estos motivos esta tesis tiene como objetivo general comprender la distribución y el papel ecológico que tienen los organismos bentónicos sobre el ecosistema bentónico de la plataforma continental antártica. Esta tesis incluye cuatro capítulos En el primer capítulo se investigan las asociaciones de ofiuras en términos de patrones de distribución y diversidad en tres regímenes ambientales y profundidades diferentes en la Península Antártica. En el segundo capítulo se evalúa el estado de salud de las poplaciones de gorgonias antárticas en un área prístina y remota en la parte más meridional de la plataforma continental del mar de Weddell. En el tercer capítulo se compara el rendimiento de dos artes de muestreo mediante la evaluación de datos cuantitativos en la plataforma continental de tres regiones oceanográficamente muy distintas en la Península Antártica. Finalmente, en el cuarto capítulo se trata de entender la forma en que una población de gorgonias afecta la diversidad de las especies de megafauna asociadas, caracterizando conjuntamente dos poblaciones de gorgonias que habitan en dos plataformas continentales muy diferentes.
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Mayer, Michaela. « Zur Ökologie der Benthos-Foraminiferen der Potter Cove (King George Island, Antarktis) = Ecology of benthic foraminifera in the Potter Cove (King George Island, Antarctica) / ». Bremerhaven : Alfred-Wegener-Institut für Polar- und Meeresforschung, 2000. http://www.gbv.de/dms/bs/toc/314065083.pdf.
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Ishman, Scott E. « Quantitative analysis of Antarctic benthic foraminifera : application to paleoenvironmental interpretations / ». The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487683049375259.
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MATULAITIS, ILONA ILMARA L. « BENTHIC FORAMINIFERAL ANALYSIS FROM BARILARI BAY, WESTERN ANTARCTIC PENINSULA MARGIN ». OpenSIUC, 2013. https://opensiuc.lib.siu.edu/theses/1129.
Texte intégralRésumé :
The temperature record from the Antarctic Peninsula (AP) shows a warming trend 3°C greater than that of the Antarctic continent (Vaughan, et al., 2003). The LARsen Ice Shelf System, Antarctica (LARISSA) project was developed as an interdisciplinary collaboration to understand the impacts of global climate change on the ice shelf systems of the Peninsula. The 2010 LARISSA cruise to the western AP margin collected the two marine sediment cores from the mouth of Barilari Bay used for this thesis, Jumbo Piston Core (JPC) 127 and Jumbo Kasten Core (JKC) 55. The 77 sediment samples collected at 10 cm intervals were sieved at 63 microns to retain foraminiferal tests, identified to the species level. The 35 most abundant foraminifera species were grouped into five assemblages with one outlier species through Hierarchical Cluster Analysis (HCA), predominantly grouped by calcareous and agglutinated foraminifera. The Principal Component Analysis (PCA) yielded two principal components, which accounted for 81.5% of the variability within the data, correlated to the species Fursenkoina spp. and Bulimina aculeata. The base of this core was found to be nearly 8000 calibrated years before present (cal. yr. BP) through radiocarbon dating of the foraminiferal tests. The PCA results were correlated with the magnetic susceptibility down core, producing a timeline of four distinct zones in the mid- to late Holocene at the outer Barilari Bay core site. The earliest zone indicated stable cold bay waters, followed by a drastic change with the incursion of warmer Circumpolar Deep Water (CDW) onto the continental shelf. The third zone of this study illustrated a period of fluctuation between the cold bay waters and the CDW, interrupted by the Little Ice Age when the ice shelf in Barilari Bay extended to the mouth of the bay. The most recent zone depicts the past 200 years of melting ice shelves and the resulting increase in primary productivity observed in the bays of the western AP, discernable from the diatom, foraminifera, and sedimentological record. This description of the benthic foraminiferal record in outer Barilari Bay increases the understanding of the timing of events in the mid- to late Holocene and will serve as a correlation to other paleoclimate proxies from the LARISSA project.
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BUSCHI, EMANUELA. « Diversity of microbiomes associated with benthic invertebrates inhabiting Antarctic ecosystems ». Doctoral thesis, Università Politecnica delle Marche, 2020. http://hdl.handle.net/11566/274555.
Texte intégralRésumé :
Il numero sempre più alto di studi condotti sui microbiomi ha evidenziato l’importanza che queste associazioni rivestono nello sviluppo, nella salute e nella fitness degli organismi con cui i microbiomi vivono associati. In ambienti estremi come l’Antartide, i microbiomi sembrano avere un’importanza cruciale nel creare interazioni fondamentali per l’adattamento dei loro ospiti. Gli obiettivi di questa tesi sono: i) studiare la biodiversità dei microbiomi associati a diversi invertebrati marini antartici, ii) esplorarne l’origine, confrontando i microbiomi associati agli organismi con le comunità batteriche che abitano nei sedimenti circostanti, e iii) verificare se i fattori ambientali svolgano un ruolo attivo nel modellare la loro composizione tassonomica. I risultati hanno mostrato che, nonostante i microbiomi associati ai policheti antartici (Leitoscoloplos geminus, Aphelocaeta palmeri, Aglaophamus trissophyllus) possano variare in modo significativo tra gli individui, è possibile individuare dei core, sia a livello intraspecifico sia interspecifico, che contribuiscono significativamente all'intera comunità batterica associata. I taxa batterici associati ai policheti sono completamente diversi da quelli presenti nei sedimenti circostanti, suggerendo una potenziale trasmissione verticale o diverse capacità adattative dei microbiomi ai due diversi “habitat”. Molteplici fattori (i.e., non solo fattori ambientali ma anche quelli biologici come lo stato fisiologico e le abitudini di alimentazione) influenzano, a diversi gradi, la composizione tassonomica dei microbiomi associati ai policheti antartici. Nella stella marina antartica Odontaster validus la posizione geografica è il principale fattore che spiega le differenze trovate nella composizione tassonomica dei microbiomi, sebbene siano state riscontrate alcune somiglianze tra individui raccolti in luoghi diversi, suggerendo la presenza di altri fattori in grado di selezionare comunità batteriche simili. La presenza esclusiva di batteri specifici associati a stelle marine che vivono in determinate aree suggerisce una potenziale trasmissione orizzontale dei microbiomi, probabilmente acquisiti attraverso diverse abitudini alimentari che le stelle marine hanno sviluppato nelle suddette aree. Questa tesi di dottorato fornisce nuove informazioni sui microbiomi antartici, evidenziando una forte variabilità della loro composizione e complessità delle relazioni con gli ospiti esaminati, potenzialmente dovute, oltre ai fattori ambientali, anche alle caratteristiche biologiche degli ospiti.Growing studies on host-associated microbiomes are highlighting the important role of microbes in the development, health and fitness of their hosts. This might be particularly true in remote and extreme environments, such as the Antarctic ecosystem, where the host and its microbiome could evolve together establishing peculiar and close interactions. This study aims: i) to investigate the biodiversity of microbiomes of different Antarctic invertebrates, ii) to explore the potential sources of the host-associated microorganisms by comparing them with microbial communities inhabiting the surrounding sediments, and iii) to verify the role of environmental setting in shaping their taxonomic composition. Results revealed that microbiomes of Antarctic polychaetes (Leitoscoloplos geminus, Aphelocaeta palmeri, Aglaophamus trissophyllus) showing significant variability among individuals, but that both intra-specific and inter-specific core microbiomes contribute for a significant fraction to the whole microbial assemblage. Bacteria associated with polychaetes were completely different from those in the surrounding sediments, suggesting a potential vertical transmission or the presence of different adaptative/selective conditions of the two “habitats”. Multiple factors (i.e., not only environmental factors but also biological ones such as physiological state and feeding habits) can influence to different extent the taxonomic composition of microbiomes associated with Antarctic polychaetes. In the Antarctic sea star Odontaster validus, the geographic location was identified as the main factor influencing the taxonomic composition of microbiomes, but this was not a general rule. In fact, high similarities were found among microbiomes of individuals collected in different locations, suggesting the presence of other drivers able to select similar microbial communities. The presence of exclusive bacterial families in sea-star microbiomes suggests a potential horizontal transmission of bacterial taxa, probably acquired through different feeding habits that the sea star might have developed in the different basins. This PhD thesis provided new information on Antarctic microbiomes, highlighting a strong variability of their composition and complexity of the relationships with the investigated hosts, potentially due to, besides environmental settings, also to hosts’ biological features.
Livres sur le sujet "Antarctic benthos"
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Cairns, Stephen D. Antarctic Scleractinia. Koenigstein : Koeltz Scientific Books, 1990.
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Zdzitowiecki, Krzysztof. Antarctic Acanthocephala. Koenigstein : Koeltz Scientific Books, 1991.
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Wägele, Johann Wolfgang. Antarctic Isopoda Valvifera. Koenigstein : Koeltz Scientific Books, 1991.
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Ullod, Núria Teixidó. Analysing benthic communities in the Weddell Sea (Antarctica) : A landscape approach = Analyse der Benthosgemeinschaften im Weddellmeer (Antarktis) : ein landschaftsökologischer Ansatz. Bremerhaven : Alfred-Wegener-Institut für Polar- und Meeresforschung, 2003.
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Voss, Joachim. Zoogeographie und Gemeinschaftsanalyse des Makrozoobenthos des Weddellmeeres (Antarktis) = : Zoogeography and community analysis of macrozoobenthos of the Weddell Sea (Antarctica). Bremerhaven : Alfred-Wegener-Institut für Polar- und Meeresforschung, 1988.
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Mayer, Michaela. Zur Ökologie der Benthos-Foraminiferen der Potter Cove (King George Island, Antarktis) = : Ecology of benthic Foraminifera in the Potter Cove (King George Island, Antarctica). Bremerhaven : Alfred-Wegener-Institut für Polar- und Meeresforschung, 2000.
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Starmans, Andreas. Vergleichende Untersuchungen zur Ökologie und Biodiversität des Mega-Epibenthos der Arktis und Antarktis = : Comparative studies on the ecology and biodiversity of the Arctic and Antarctic Mega-Epibenthos. Bremerhaven : Alfred-Wegener-Institut für Polar- und Meeresforschung, 1997.
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Voss, Joachim. Zoogeographie und Gemeinschaftsanalyse des Makrozoobenthos des Weddellmeeres (Antarktis) = : Zoogeography and community analysis of macrozoobenthos of the Weddell Sea (Antarctica). Bremerhaven : Alfred-Wegener-Institut für Polar- und Meeresforschung, 1988.
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Covadonga Orejas Saco del Valle. Role of benthic cnidarians in energy transfer processes in the southern ocean marine ecosystem (Antarctica) : Rolle der bodenlebenden Nesseltiere im Stofffluss des marinen Ökosystems des Südpolarmeeres (Antarktis). Bremerhaven : Alfred-Wegener-Institut für Polar- und Meeresforschung, 2001.
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Kowalke, Jens. Energieumsätze benthischer Filtrierer der Potter Cove (King Geroge Island, Antarktis) = : Energy budgets of benthic suspension feeding animals of the Potter Cove (King George Island, Antarctica). Bremerhaven : Alfred-Wegener-Institut für Polar- und Meeresforschung, 1998.
Trouver le texte intégralChapitres de livres sur le sujet "Antarctic benthos"
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Arntz, W. E., et V. A. Gallardo. « Antarctic Benthos : Present Position and Future Prospects ». Dans Antarctic Science, 243–77. Berlin, Heidelberg : Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-642-78711-9_16.
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Pineda-Metz, Santiago E. A. « Benthos-Pelagos Interconnectivity : Antarctic Shelf Examples ». Dans YOUMARES 9 - The Oceans : Our Research, Our Future, 211–23. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-20389-4_11.
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Jazdzewski, Krzysztof, Claude De Broyer, Magdalena Pudlarz et Dariusz Zielinski. « Seasonal fluctuations of vagile benthos in the uppermost sublittoral of a maritime Antarctic fjord ». Dans Ecological Studies in the Antarctic Sea Ice Zone, 89–96. Berlin, Heidelberg : Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-59419-9_13.
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Brandt, A., C. De Broyer, B. Ebbe, K. E. Ellingsen, A. J. Gooday, D. Janussen, S. Kaiser et al. « Southern Ocean Deep Benthic Biodiversity ». Dans Antarctic Ecosystems, 291–334. Chichester, UK : John Wiley & Sons, Ltd, 2012. http://dx.doi.org/10.1002/9781444347241.ch10.
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Campana, Gabriela L., Katharina Zacher, Fernando R. Momo, Dolores Deregibus, Juan Ignacio Debandi, Gustavo A. Ferreyra, Martha E. Ferrario, Christian Wiencke et María L. Quartino. « Successional Processes in Antarctic Benthic Algae ». Dans Antarctic Seaweeds, 241–64. Cham : Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-39448-6_12.
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Oppenheim, D. R. « A Preliminary Study of Benthic Diatoms in Contrasting Lake Environments ». Dans Antarctic Ecosystems, 91–99. Berlin, Heidelberg : Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-84074-6_9.
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Clarke, Andrew. « Benthic marine habitats in Antarctica ». Dans Foundations for Ecological Research West of the Antarctic Peninsula, 123–33. Washington, D. C. : American Geophysical Union, 1996. http://dx.doi.org/10.1029/ar070p0123.
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Matsuda, O., S. Ishikawa et K. Kawaguchi. « Seasonal Variation of Particulate Organic Matter Under the Antarctic Fast Ice and its Importance to Benthic Life ». Dans Antarctic Ecosystems, 143–48. Berlin, Heidelberg : Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-84074-6_14.
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Lo Giudice, Angelina, Maurizio Azzaro et Stefano Schiaparelli. « Microbial Symbionts of Antarctic Marine Benthic Invertebrates ». Dans Springer Polar Sciences, 277–96. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-02786-5_13.
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Clarke, Andrew. « The distribution of Antarctic marine benthic communities ». Dans Foundations for Ecological Research West of the Antarctic Peninsula, 219–30. Washington, D. C. : American Geophysical Union, 1996. http://dx.doi.org/10.1029/ar070p0219.
Texte intégralActes de conférences sur le sujet "Antarctic benthos"
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Stewart, Joseph, Peter Spooner, Andrea Burke, Tianyu Chen, Tao Li, James Rae, Jenny Roberts, Victoria Peck, Qian Liu et Laura Robinson. « Productivity and Dissolved Oxygen Controls on the Southern Ocean Deep-Sea Benthos during the Antarctic Cold Reversal ». Dans Goldschmidt2020. Geochemical Society, 2020. http://dx.doi.org/10.46427/gold2020.2463.
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Gerber, Hans W., et Gu¨nther F. Clauss. « MABEL : Recovery Operation of the First Long-Term Heavy Benthic Laboratory in the Deep Sea of Antarctica ». Dans ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-80251.
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This paper deals with the recovery operation of the bottom station MABEL (Multidisciplinary Antarctic Benthic Laboratory) with a mass of 1,7 tons in air that has been deployed in December 2005 from the German research vessel Polarstern, by means of a release transponder at a water depth of 1850 m, close to the shelf ice edge near the German polar research station Neumayer. The project is run under the umbrella of the Italian Antarctic programme by the project leader INGV (Istituto Nazionale di Geofisica i Vulcanlogia) /1/. During the cruise ANT XXV-2 of the Polarstern (organized by the German AWI - Alfred-Wegner-Institut) the German partners TFH Berlin and TU Berlin have been participating with their module MODUS (Mobile Docker for Underwater Sciences) to recover the station from the deep sea. The special circumstances in the Antarctic sea — the ice coverage of the deployment area and the tight time schedule for the operation — make such an operation quite delicate. This paper describes the special technology used both for the station and the recovery module. The operation itself will be discussed, showing the data of operation using a combined tracking of GPS-data and the underwater positioning system Posidonia of the Polarstern. The special circumstance of the operation was the inadequate data of the position achieved during the deployment, so that a safe search strategy had to be found. The mission ended successfully on December 16th, 2008 with the recovery of the MABEL station. Simulations for the system behaviour will be shown.
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Whittle, Rowan, Fernanda Quaglio, James D. Witts, Aaron W. Hunter et Huw Griffiths. « THE EVOLUTION OF BENTHIC ECOLOGY IN THE CENOZOIC OF ANTARCTICA ». Dans GSA 2020 Connects Online. Geological Society of America, 2020. http://dx.doi.org/10.1130/abs/2020am-355689.
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Whittle, Rowan J., James D. Witts, Vanessa C. Bowman, J. Alistair Crame, Jane E. Francis et Jon Ineson. « NATURE AND TIMING OF BIOTIC RECOVERY IN ANTARCTIC BENTHIC MARINE ECOSYSTEMS FOLLOWING THE CRETACEOUS–PALEOGENE MASS EXTINCTION ». Dans GSA Annual Meeting in Phoenix, Arizona, USA - 2019. Geological Society of America, 2019. http://dx.doi.org/10.1130/abs/2019am-333664.
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Harwood, David M. « BUOYANT MACROALGAL TRANSPORT OF BENTHIC EPIPHYTIC DIATOMS INTO DEEP-SEA SOUTHERN OCEAN SEDIMENTS : A NEW PROXY FOR ANTARCTIC PALEOENVIRONMENTAL CHANGE AND AN UNRESOLVED COMPONENT OF THE ANTARCTIC PELAGIC ECOSYSTEM ». Dans GSA Annual Meeting in Denver, Colorado, USA - 2016. Geological Society of America, 2016. http://dx.doi.org/10.1130/abs/2016am-287899.
Texte intégralRapports d'organisations sur le sujet "Antarctic benthos"
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Jerosch, K., F. K. Scharf, D. Deregibus, G. L. Campana, K. Zacher, H. Pehlke, U. Falk, H. C. Hass, M L Quartino et D. Abele. Habitat modeling as a predictive tool for analyzing spatial shifts in Antarctic benthic communities due to global climate change. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2017. http://dx.doi.org/10.4095/305870.
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