Academic literature on the topic 'Aquatic consumers'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Aquatic consumers.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Aquatic consumers"
1
Possamai, B., DJ Hoeinghaus, and AM Garcia. "Shifting baselines: Integrating ecological and isotopic time lags improves trophic position estimates in aquatic consumers." Marine Ecology Progress Series 666 (May 20, 2021): 19–30. http://dx.doi.org/10.3354/meps13682.
Full textAbstract:
Nitrogen stable isotope ratios (δ15N) are routinely used to estimate consumer trophic positions (TPs). This method is very sensitive to the chosen isotopic baseline, which should incorporate all temporal isotopic variability occurring in the base of the food web sustaining the consumers. However, there is still no consensus on the different methods to represent time intervals for isotopic assimilation. It is uncertain if researchers should compute a single baseline obtained by averaging δ15N source values across all time periods, multiple baselines based on δ15N source values collected concomitantly with consumers, or consider a time lag between sources and consumers. Aiming to provide empirical evidence to help select the best option, we designed 4 methods using different temporal lags between consumers and producers based on a 9 yr time series of carbon and nitrogen stable isotopes in an estuary. The 4 tested baseline methods considered the δ15N average of producers sampled in all years (Global); the same season as consumers (Concomitantly); the season before the collection of consumers (Delayed); and the previous season as well as the same season of consumer sampling (Interpolation). Comparison of results with an expected model (based on stomach content data) showed that the Delayed method is the most appropriate. We conclude that time lags in the incorporation of stable isotope values between sources and consumers must be considered in baseline δ15N calculations to improve TP estimates and provide more reliable modeling results. Additionally, we provide other recommendations to improve sampling designs when using stable isotopes in TP estimations.
2
Zanden, M. Jake Vander, and Joseph B. Rasmussen. "PRIMARY CONSUMER δ13C AND δ15N AND THE TROPHIC POSITION OF AQUATIC CONSUMERS." Ecology 80, no. 4 (June 1999): 1395–404. http://dx.doi.org/10.1890/0012-9658(1999)080[1395:pccana]2.0.co;2.
Full text
3
Budhathoki, Mausam, Danny Campbell, Ben Belton, Richard Newton, Saihong Li, Wenbo Zhang, and David Little. "Factors Influencing Consumption Behaviour towards Aquatic Food among Asian Consumers: A Systematic Scoping Review." Foods 11, no. 24 (December 14, 2022): 4043. http://dx.doi.org/10.3390/foods11244043.
Full textAbstract:
Asia accounts for over 70% of total global aquatic food consumption, but aquatic food consumption behaviours and attitudes among Asian consumers are poorly documented and understood. This paper synthesises literature on factors influencing aquatic food consumption behaviour in Asia and the potential to support transitions toward more sustainable food consumption patterns. We identified 113 studies for inclusion in a scoping review, and identified five clusters of publications: (1) product attributes, availability, and accessibility (24% of publications); (2) willingness to pay for aquatic foods (25%); (3) psychosocial factors (e.g., attitudes and subjective norms) (17%); (4) sociodemographic and lifestyle factors (21%); and (5) miscellaneous factors, including food safety and social status (13%). This study indicates that multiple interacting factors influence aquatic food consumption behaviours among Asian consumers, among which price is central. Knowledge of, and attitudes toward, the perceived quality and safety of aquatic foods were identified as important but were mediated by household characteristics. Sustainable production practices, country of origin, and ecolabels were found to be less influential on consumption behaviour. We found that improving consumers’ knowledge and attitudes about the quality and safety of aquatic foods might positively influence aquatic food consumption behaviour. Future multidisciplinary research is required to better understand interactions among the multiple factors that influence Asian consumers’ aquatic food consumption behaviour.
4
McCaffery, Magnus, and Lisa Eby. "Beaver activity increases aquatic subsidies to terrestrial consumers." Freshwater Biology 61, no. 4 (February 1, 2016): 518–32. http://dx.doi.org/10.1111/fwb.12725.
Full text
5
Garcia, Alexandre M., David J. Hoeinghaus, João P. Vieira, Kirk O. Winemiller, David M. L. Motta Marques, and Marlise A. Bemvenuti. "Preliminary examination of food web structure of Nicola Lake (Taim Hydrological System, south Brazil) using dual C and N stable isotope analyses." Neotropical Ichthyology 4, no. 2 (June 2006): 279–84. http://dx.doi.org/10.1590/s1679-62252006000200014.
Full textAbstract:
Taim Ecological Reserve is located within the Taim Hydrological System and was created to protect a heterogeneous and productive landscape harboring exceptional biological diversity in southern Brazil. Using stable isotope ratio analyses of carbon (delta13C) and nitrogen (delta15N), we provide a preliminary description of the food web structure, including estimates of production sources supporting fish populations and vertical trophic structure, within a representative lake of this system. A total of 21 organisms (5 macrophytes, 3 mollusks and 13 adult fishes) representing 16 species were collected for isotope analysis. Fishes had delta13C values ranging from -24.30º/oo to -28.31º/oo , showing concordance with the range of values observed for macrophytes (-25.49 to -27.10º/oo), and suggesting that these plants could be a major carbon source supporting these fishes. delta13C signatures of Corbicula (-30.81º/oo) and Pomacea (-24.26º/oo) indirectly suggest that phytoplankton and benthic algae could be alternative carbon sources for some consumers. Nitrogen isotope ratios indicated approximately three consumer trophic levels. The pearl cichlid Geophagus brasiliensis was a primary consumer. Two catfishes (Trachelyopterus lucenai and Loricariichthys anus) were secondary consumers. Two congeneric pike cichclids (Crenicichla lepidota and C. punctata), a catfish (Pimelodus maculatus) and the characids Astyanax fasciatus and Oligosarcus robustus were tertiary consumers. Further studies including additional primary producers and consumers and greater sample numbers should be conducted to provide a more complete and detailed description of food web structure and dynamics within the reserve.
6
Vander Zanden, M. J., G. Cabana, and J. B. Rasmussen. "Comparing trophic position of freshwater fish calculated using stable nitrogen isotope ratios (δ15N) and literature dietary data." Canadian Journal of Fisheries and Aquatic Sciences 54, no. 5 (May 1, 1997): 1142–58. http://dx.doi.org/10.1139/f97-016.
Full textAbstract:
Stable nitrogen isotope ratios ( delta 15N) are commonly used to represent the trophic structure of aquatic systems, yet the ability of delta 15N to indicate the trophic position of aquatic consumers remains untested using traditional dietary methods. Interpreting the delta 15N of aquatic consumers relative to large, long-lived primary consumers such as unionid mussels provides a continuous measure of an organism's trophic position that adjusts for among-system variation in baseline delta 15N. We used this method to estimate the trophic position of eight littoral fish species from 36 lakes in Ontario and Quebec. We validated these delta 15N measures of trophic position by compiling literature dietary data from 342 populations of these same fish species and calculated a continuous measure of trophic position for each population. Mean dietary trophic position estimates corresponded closely to 15N estimates, with mean trophic position ranging from 3.3 for pumpkinseed (Lepomis gobbosus) to 4.4 for walleye (Stizostedion vitreum). Both methods indicated approximately one trophic level of variation among populations of a species. This study confirms the ability of baseline-adjusted delta 15N to represent the trophic position of aquatic consumers.
7
Malik, Tariq H., and Jae Chul Choi. "Social Media Versus Personal Experience in the Consumer’s Apprehension on Imported Food Security and Safety Dilemma." SAGE Open 11, no. 2 (April 2021): 215824402110074. http://dx.doi.org/10.1177/21582440211007486.
Full textAbstract:
South Korea imports a large amount of agricultural and aquatic food products from China, which meets its food security. However, the import from China raises food safety questions, leading to food safety apprehension. We explored the source of the Korean consumer’s apprehension. Based on the apprehension reduction theory (ART) developed from interviews with Korean consumers in the first stage of the study, we conducted a survey to assess the social media as an indirect source of information and direct experience of the consumer in the second stage of the study. We received 504 responses, of which 1/3 of the respondents had visited China in the last year. Using FSS (Food Safety Satisfaction) as the dependent variable (1— low to 5— high), we link information from the social media vis-à-vis direct experience and made three discoveries. (a) The information quantity of social media increases the consumer’s apprehension, partially refuting the ART. (ii) FSS increased in response to information flow from the direct experience of the consumer with Chinese imported food. (c) The direct information from experience mediates the effects of indirect information (social media) on apprehension about agricultural and aquatic product imports. We made three inferences. First, information quantity and quality have separated roles in the ART. Second, social media increases the free-market style information flow, turning legitimate products to illegitimate and vice versa. Third, the collective irrationality from the information quantity needs institutional bricolage to legitimize the chaotic nature of the untamed information.
8
Smith, Val H. "Competition between consumers." Limnology and Oceanography 36, no. 4 (June 1991): 820–23. http://dx.doi.org/10.4319/lo.1991.36.4.0820.
Full text
9
Bennett, Abigail, Emma Rice, Park Muhonda, Emmanuel Kaunda, Sam Katengeza, Lenis Saweda O. Liverpool-Tasie, Ben Belton, et al. "Spatial analysis of aquatic food access can inform nutrition-sensitive policy." Nature Food 3, no. 12 (December 15, 2022): 1010–13. http://dx.doi.org/10.1038/s43016-022-00642-4.
Full textAbstract:
AbstractAquatic foods are critical for food and nutrition security in Malawi, but it is unclear which populations benefit from different aquatic foods and what factors shape food access. Spatial analysis of food flows across value chains from Lake Malawi to domestic consumers shows that usipa (Engraulicypris sardella) reaches more consumers than chambo (Oreochromis karongae) across all Malawi districts, particularly rural populations. Higher number of markets, nutrient content, and overall supply coupled with lower retail prices and volumes make usipa more accessible to consumers than chambo. Spatial analysis of food flows can guide policymakers towards supporting fisheries that reach vulnerable populations and designing interventions that enhance physical and economic access to fish.
10
Ebm, Nadine, Fen Guo, Michael T. Brett, Stuart E. Bunn, and Martin J. Kainz. "Polyunsaturated fatty acids in fish tissues more closely resemble algal than terrestrial diet sources." Hydrobiologia 848, no. 2 (November 16, 2020): 371–83. http://dx.doi.org/10.1007/s10750-020-04445-1.
Full textAbstract:
AbstractThe River Continuum Concept implies that consumers in headwater streams have greater dietary access to terrestrial basal resources, but recent studies have highlighted the dietary importance of high-quality algae. Algae provide consumers with physiologically important omega-3 (n-3) polyunsaturated fatty acids (PUFA), particularly eicosapentaenoic acid (EPA). However, terrestrial plants and most benthic stream algae lack the long-chain (LC) n-3 PUFA docosahexaenoic acid (DHA, 22:6n-3), which is essential for neural development in fish and other vertebrates. We sampled subalpine streams to investigate how the PUFA composition of neural (brain and eyes), muscle, and liver tissues of freshwater fish is related to their potential diets (macroinvertebrates, epilithon, fresh and conditioned terrestrial leaves). The PUFA composition of consumers was more similar to epilithon than to terrestrial leaves. Storage lipids of eyes most closely resembled dietary PUFA (aquatic invertebrates and algae). However, DHA and arachidonic acid (ARA, 20:4n-6) were not directly available in the diet but abundant in organs. This implies that algal PUFA were selectively retained or were produced internally via enzymatic PUFA conversion by aquatic consumers. This field study demonstrates the nutritional importance of algal PUFA for neural organs in aquatic consumers of headwater regions.
Dissertations / Theses on the topic "Aquatic consumers"
1
Burian, Alfred. "Impact of food quality on aquatic consumers : Behavioral and physiological adjustments." Doctoral thesis, Stockholms universitet, Institutionen för ekologi, miljö och botanik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-128828.
Full textAbstract:
Food quantity and quality together determine growth rates of consumers and the utilisation efficiencies of available resources in aquatic and terrestrial ecosystems. The effect of food quality on the performance of consumers is dependent on both, its direct influence on ingestion and assimilation rates, and on the behavioural and physiological adjustments of consumers to their food environment. The main target of this thesis was to investigate the nature and scope of behavioural and physiological adjustments in consumers and assess the resulting consequences for consumers’ fitness and ecosystem-wide nutrient flows. In paper I, we investigated the extent of elemental homeostasis across several taxonomic groups of planktonic herbivores. We found that adjustments in elemental ratios (C:N:P) in body tissues are an important physiological response of heterotrophic flagellates, but that in ciliates and multi-cellular organisms C:N:P ratios varied much less than in their algal prey. Hence, alternative regulatory mechanisms determine the reactions of metazoan zooplankton to decreases in food quality. In paper II, we developed a theoretical model to explore regulation in behaviour and digestive physiology of consumers to changes in the food environment. Our results demonstrate that feeding and digestion of consumers are determined by trade-offs between benefits and costs of investments in these processes. We revealed that the flexibility in consumers’ behaviour and physiology had strong influences on assimilation rates and efficiencies and thereby affected growth rates and a wide range of ecosystem functions. In paper III, we investigated the scope and consequences of adjustments in feeding and assimilation rates of copepods exposed to different diets. An important finding was that consumers can use resources, which are available in surplus, to increase the uptake of a limiting nutrient. Such nutrient interconversion led to co-limitation, the simultaneous limitation of copepods by two different nutrients. Finally, in paper IV, we aimed to test the effect of food quality on population dynamics in the field. We investigated zooplankton populations in tropical soda-lakes, an environment with a surplus of planktonic food sources that thus provides an ideal setting for investigations of food quality. However, we found that the hatching of resting eggs from lake sediments was the main driver of zooplankton bloom formation resulting in non-cyclical dynamics that were not related to food quality. These findings contributed to our understanding under which circumstance and by which mechanisms food quality affects the performance of consumers. My results highlight that food quality has not only direct effects on consumers’ growth but also triggers behavioral and physiological responses in consumers to maximize their fitness.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript.
2
Douglass, James G. "Community dynamics in submersed aquatic vegetation: Intermediate consumers as mediators of environmental change." W&M ScholarWorks, 2008. https://scholarworks.wm.edu/etd/1539616634.
Full textAbstract:
Natural ecosystems are strongly affected by changes in resource supply (bottom-up forces) and by changes in upper trophic levels (top-down forces). The extent to which these processes impact a system depends largely on the responses of organisms at middle trophic levels. In seagrass beds, a group of mid-level consumers known as mesograzers form a critical link in the chain of impact, connecting seagrass and epiphytic algae with predatory fishes and crustaceans. I observed dramatic seasonal and interannual changes in mesograzer abundance and species composition in eelgrass (Zostera marina) beds of lower Chesapeake Bay, Virginia, and endeavored to explain the top-down and bottom-up causes and consequences of those changes with field studies and controlled experiments. A field cage experiment showed that grazing, predation and nutrient enrichment all had strong effects on the eelgrass community, but that the effects of each factor varied for different community components (Chapter 1). A second experiment delved deeper into the predation dynamic by manipulating the diversity of both predators and mesograzers in macroalgal mesocosms. Increasing predator diversity increased the strength of predation, but increasing mesograzer diversity conferred resistance to some types of predation (Chapter 2). to assess the influence of top-down and bottom-up forces in a more natural context, I analyzed the long-term changes in biotic and abiotic components of an eelgrass bed at the Goodwin Islands National Estuarine Research Reserve. I found that abiotic processes had strong effects on both consumer and resource abundance, and could therefore initiate either top-down or bottom-up control of eelgrass community structure (Chapter 3). to examine this top-down and bottom-up control in more detail I explicitly compared the ecological relationships seen in the field to those observed in mesocosm experiments. Mesocosm experiments tended to find a greater influence of top-down effects and a lesser influence of bottom-up effects, relative to field observations (Chapter 4). Finally, I took a snapshot of the eelgrass food web itself by examining the gut contents and stable carbon and nitrogen isotopic ratios of predators, mesograzers, and plants. I found that direct grazing on eelgrass does occur, but that microalgae and detritus provide the main trophic support for the epifaunal community (Chapter 5). Overall, my results suggest that both top-down and bottom-up forces control eelgrass community structure via mesograzers, but that top-down control in the field is more subtle and more intimately tied with bottom-up control than has been indicated by some manipulative experiments.
3
Becker, Allison L. "Aquatic insects as an energetic subsidy to riparian consumers in the Olman River Basin, Alberta." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences, c2012, 2012. http://hdl.handle.net/10133/3315.
Full textAbstract:
Freshwater and terrestrial ecosystems are connected through biomass exchanges such as the flow of predators, prey, nutrients and detritus between them. Emerging aquatic insects provide an alternate food source to riparian consumers often termed an allochthonous subsidy. Stable isotope analyses of naturally occurring carbon and nitrogen is effective for tracing energetic food sources to consumers. This thesis evaluated whether stable isotope analysis would be effective in the Oldman River Basin, Alberta. Aquatic and riparian primary consumers are distinct in their isotopic signatures and valid for to use in stable isotope analysis. Stable isotope modelling was then used to evaluate the proportional contribution of aquatic insects to riparian spider and beetle diets. Carbon analysis showed an overall aquatic insect contribution of 25 % and 18 % for spiders and beetles, respectively; while nitrogen analysis showed an overall contribution of 36 % and 20 %, respectively. The spatial extent of the aquatic insect contribution upland from the river was shown to decrease from 50 - 55 % at 1 m to 0 % at 30 m for both consumers using carbon, and from 35 - 40 % at 1 m to 0 % at 40 m using nitrogen. Finally, regression modelling of the size of a river and the spatial scale of an aquatic insect dietary contribution showed a significant relationship, indicating larger water bodies support higher production of aquatic insects. A meta-analysis of published literature applied to this model also indicated a significant relationship between the size of the river and the extent of an aquatic insect contribution.xii, 126 leaves m ; 29 cm
4
Tao, Juan. "Riverine food webs and the effects of human disturbance on the contribution and quality of food sources to aquatic consumers in sub-tropical rivers." Thesis, Griffith University, 2017. http://hdl.handle.net/10072/371244.
Full textAbstract:
Understanding flows of energy and nutrients through food webs can provide important insights into mechanisms influencing the structure and function of riverine ecosystems and ecological responses to human activities. However, it is not well understood how changing land use, river impoundment and flow alteration affect the quality and quantity of food resources supporting riverine food webs. The broad aims of this thesis were to determine: (1) the effects of human disturbances on basal food sources and food quality for aquatic consumers in sub-tropical rivers in south-east Queensland (SEQ); and (2) the potential for poor food quality to be causing low recruitment of the threatened Australian lungfish (Neoceratodus forsteri Krefft, 1870).
Understanding food webs is important and useful for planning environmental conservation, management and restoration. However, research on food webs has not been uniformly conducted across different parts of the world; it tends to be concentrated in specific areas or ecosystem types, and this may limit our understanding of food webs and ecosystem processes. Therefore, before answering the research questions posed, I first examined trends in food web research over time by analysing publication data from Web of Science (WOS). The review focused on the ecosystem types studied, countries in which the studies were conducted, and which countries collaborated on the studies. A total of 20,239 publications on food webs were examined, and food web research has increased dramatically since the 1990s. Most publications were focused on aquatic ecosystems, and North America and Europe contributed far more studies than Africa and South America. Collaboration among individual authors and countries has become increasingly prevalent. The USA and Canada were consistently the two most productive countries, and had the most frequent collaborations. The results indicate that food web studies from terrestrial ecosystems also require more attention in the future, especially countries from Africa and South America. Importantly, the majority of freshwater food web research has been conducted in temperate systems in the northern hemisphere. The comparatively small number of studies conducted in tropical, sub-tropical or arid freshwater systems may limit our ability to develop a general understanding and synthesis of the key factors influencing freshwater food web processes globally.
The relative importance of allochthonous sources versus autochthonous sources to aquatic consumers varies in predictable ways along longitudinal gradients in rivers. However, it remains unclear how this will change under human disturbances, such as river impoundment, flow alteration and agricultural land use. I examined the potential effects of these anthropogenic disturbances on aquatic food webs by using stable isotopes (δ13C and δ15N) from six sites in each of two comparable sub-tropical rivers, the Brisbane River and Mary River in SEQ. The Brisbane River downstream was heavily affected by impoundment and flow alteration compared to the upstream and to the Mary River. Both catchments had similar levels of agricultural land use. The results showed that the main sources of variation in δ13C and δ15N isotopic values of most basal sources, invertebrates, and fish trophic guilds were due to the effects of relative catchment position within rivers, with minimal overall differences between rivers and seasons. Most of the basal sources and consumers showed a general enrichment in δ15N values from upstream to downstream in both rivers, which could be caused by increased anthropogenic nitrogen inputs and changed nitrogen cycling in riparian soils. Mixing model analyses revealed that most of the consumers examined in both rivers were supported by autochthonous carbon sources, with no detectable influence of flow alteration or land use. In contrast, the reliance of consumers on food sources was changed to a higher contribution from autochthonous pelagic sources in Brisbane River sites downstream of the dam.
Fatty acids (FA) play an important role in aquatic food webs and are potentially powerful biomarkers for studying the structure and function of ecosystems. However, there has been limited research characterizing FA profiles among potential food sources and how they vary spatially along natural and anthropogenic disturbance gradients in rivers. Quantifying these major sources of variation in FA profiles of aquatic food sources is a critical pre-requisite to understanding variation in food quality for fish and other higher consumers and can contribute to more effective aquatic ecosystem conservation and management. I investigated the FA composition of nine potential food sources for higher consumers (including primary producers and invertebrate primary consumers) collected from eight sites in two sub-tropical rivers (Brisbane River and Mary River) subjected to varying degrees of human disturbance. Different food sources had distinctive FA profiles, and several functionally important unsaturated FA were found to bioaccumulate with increasing trophic position. Partial redundancy analysis (pRDA) was conducted to separate the effects of food source category (taxa) and environment (site). Taxa and site together explained 70.4 % of the variation in FA profiles, though taxa alone accounted for most of this (90.6 %). I found significant spatial variation in FA composition for several food sources that were potentially related to flow alteration, but the effects were weak and not uniform across taxa.
The Australian lungfish, Neoceratodus forsteri Krefft, 1870, is federally listed threatened species whose long-term persistence is at risk due to land use intensification, water resource development, and other human pressures. Changes in the availability of high-quality food resources for this species may impact recruitment and contribute to population declines. I analysed the fatty acid (FA) composition of lungfish eggs and fin tissues from two locations with contrasting flow alteration resulting from a large impoundment in the Brisbane River. I hypothesised that flow alteration alters the FA composition of important dietary items for N. forsteri which will translate to the body tissues and eggs. The contribution of each food source was estimated with mixing models using carbon and nitrogen stable isotopes. Although no negative effect on FA composition on tissues was detected from flow alteration, the stable isotope analysis demonstrated FA difference in lungfish eggs could be attributed to changes in their diet.
To conclude, my studies found that: (1) current understanding on aquatic food web processes could be biased towards temperate systems and should be modified through conducting more studies in other systems; (2) consumers in south-east Queensland sub-tropical rivers were largely supported by algal basal sources, regardless of the influence of human disturbance; (3) basal food sources and primary aquatic consumers varied in nutritional quality and possessed distinctive FA profiles, but spatial variation in FA of individual food sources was relatively low and unaffected by human disturbances associated with dams and land use; (4) the low availability of high-quality food sources could potentially be the reason for low concentrations of FAs in lungfish eggs and potentially explain the low recruitment success of this threatened species; (5) the Wivenhoe dam increased the contribution of autochthonous pelagic sources to consumers in the Brisbane River sites downstream of the dam, but did not show a negative effect on lungfish egg quality; (6) catchment land use increased the δ15N values of sources and consumers probably through increasing anthropogenic nutrient inputs and changing nitrogen cycling in riparian soils. My studies indicate that a food web approach, focusing in particular on high-quality food sources that sustain the growth and reproduction of consumers, can inform river ecosystem conservation and management.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
Full Text
5
Fagernäs, Zandra. "How will climate change affect benthic primary producers and consumers? : An experimental study on periphyton and aquatic snails." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-94525.
Full textAbstract:
The global climate is predicted to go through great changes in the 21st century, which will have impacts on ecosystems all over the world. Aquatic ecosystems will be affected by higher annual temperatures and increased runoff from surrounding terrestrial areas. The increased runoff will cause more terrestrial organic matter (TOM) to reach the waters, which will elevate levels of dissolved organic carbon and nutrients. The higher temperature, changed water color and increased nutrient concentration are together bound to affect aquatic systems, but exactly how the systems will respond is yet unclear. The aim of this study was to investigate how periphyton and benthic grazers will react to higher temperatures and elevated amounts of TOM in the water. This was done by measuring production of periphyton and growth rates of the snail species Gyraulus acronicus when placed in treatments with higher temperature, more TOM or a combination of these two. Higher temperature was found to have a negative effect on periphyton production, while increased amounts of TOM alone had a positive effect, and the combination of these two lowered production. The results on snail performance were in most cases non-significant, but the results still suggest that possible future effects of more TOM and higher temperature on the snails will be negative.
6
Lima, Vinicius Neres de. "Estudos de estruturas tróficas e de impactos antropogênicos de córregos do sistema hidrográfico Guapi-Macacu: isótopos estáveis." Universidade do Estado do Rio de Janeiro, 2008. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=1162.
Full textAbstract:
Usamos a distribuição natural dos isótopos estáveis de carbono e nitrogênio para investigar qual é o principal recurso alimentar basal para as teias tróficas dos córregos florestados do sistema hidrográfico Guapi-Macacu e avaliamos se os isótopos estáveis de carbono e nitrogênio de consumidores aquáticos respondem ao uso e ocupação do solo local neste sistema hidrográfico. As hipóteses do presente trabalho são: (1) a principal fonte de energia para os animais de córregos florestados é fornecida pela produção autóctone, o perifíton; (2) as δ13C e δ15N dos consumidores aquáticos são relacionadas positivamente com as percentagens das áreas impactadas por agricultura, pastagem e ocupação urbana. Coletamos perifíton, matéria orgânica particulada fina e animais em vinte e um córregos para análise de isótopos estáveis de carbono e nitrogênio. Usamos fotos aéreas para classificar e calcular a área de uso antrópico em um raio de duzentos metros das coordenadas geográficas do ponto de coleta. O perifíton foi o recurso basal para: os peixes predadores, Characidium sp., Rhamdioglanis sp., Trichomycterus sp.; o peixe onívoro Phalloceros caudimaculatus; o peixe pastador, Schizolecis guntheri; o camarão onívoro, Macrobrachium potiuna; os caranguejos onívoros, Trichodactylus sp.; os Plecoptera predadores, Anacroneuria sp.; os Odonata predadores, Aeshnidae sp. e Libellulidae sp. A matéria proveniente da vegetação terrestre foi o principal recurso dos Trichoptera cortador e coletor-filtrador Phylloicus sp. e Smicridea sp., respectivamente. A δ13C dos Rhamdioglanis sp. foi marginalmente relacionada com a percentagem da área de impacto antrópico (p=0,072; N=6). As δ13C dos Anacroneuria sp., dos Smicridea sp., dos Characidium sp., dos Hypoptomatinae, dos Macrobrachium spp., dos Phalloceros caudimaculatus, dos Scleromystax barbatus e dos Trichomycterus sp. não foram relacionadas com a percentagem da área impactada. Apenas os Macrobrachium spp. (p=0,052; N=11) e os S. barbatus (p=0,069; N=6) tiveram suas δ15N marginalmente relacionadas com a percentagem da área de impactada. Estes resultados sugerem que a δ13C e a δ15N dos consumidores aquáticos não foram bons indicadores de impacto local no sistema hidrográfico Guapi-Macacu.We used the natural distribution of stable isotopes of carbon and nitrogen to investigate the principal basal food resources for the food web of the forested streams of the Guapi-Macacu watershed system and we evaluated if the stable isotopes of carbon and nitrogen of aquatic consumers responded to the land use and occupation in the catchment. The hypotheses of the present work are: (1) the principal energy source for the animals from forested streams comes from autochthonous production, the periphyton; (2) the δ13C and δ15N of the aquatic consumers are positively related to the percentage of the impacted areas by agriculture, pasture and urban occupation. We collected periphyton, fine particulate organic matter and animals in twenty one streams for stable isotopes analyses of carbon and nitrogen. We used aerial photos to classify and calculate the area of human use in a radius of two hundred meters from the geographic coordinate of the collection point. Periphyton was the basal resource for: the predatory fish Characidium sp., Rhamdioglanis sp., Trichomycterus sp.; the omnivorous fish Phalloceros caudimaculatus; the grazer fish, Schizolecis guntheri; the omnivore shrimp, Macrobrachium potiuna; the omnivore crab, Trichodactylus sp.; the predators Plecoptera, Anacroneuria sp.; the predators Odonata, Aeshnidae sp. e Libellulidae sp.. The material proceeding from terrestrial vegetation was the principal source of the scraper and collector-filter Trichoptera, Phylloicus sp. and Smicridea sp., respectively. The δ13C of Rhamdioglanis sp. was marginally related to the percentage of human impact area (p=0,072; N=6). The δ13C of the Anacroneuria sp., Smicridea sp., Characidium sp., Hypoptomatinae, Macrobrachium spp., Phalloceros caudimaculatus, Scleromystax barbatus and the Trichomycterus sp. were not related to the percentage of the impacted area. Only the Macrobrachium sp. (p=0,052; N=11) and the S. barbatus (p=0,069; N=6) had their δ15N marginally related to the percentage of the impacted area. These results suggest that the δ13C e a δ15N of the aquatic consumers were not good indicators of local impact in the Guapi-Macacu watershed system.
7
Mackey, Andrew. "Dynamics of baseline stable isotopes within a temperate coastal ecosystem: Relationships and projections using physical and biogeochemical factors." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2015. https://ro.ecu.edu.au/theses/1622.
Full textAbstract:
Measurements of carbon (13C/12C; δ13C) and nitrogen (15N/14N; δ15N) stable isotope ratios have become important tools for: estimating energy flow and trophic positions in aquatic foodwebs; comparing food webs; and aiding in the tracking of wide-ranging consumers. However, each of these applications requires accurate measurements of isotopic signatures in organisms at or near the base of the food web (e.g. autotrophs and their consumers), which act as basal reference points from which to calibrate inferences. Therefore, understanding variations in isotopic baselines, and the mechanisms leading to their variability, is crucial for food web ecology.
Using the shallow temperate reefs along the lower west coast of Australia as a test case, the broad aim of this thesis was to determine isotopic variations in a coastal food web and their relationship with surrounding environmental factors or food sources, to determine the suitability and issues for using such baselines in interpreting trophic links and positions in food webs and predicting shifts in isotopic signatures across broad spatial and temporal scales. To achieve this, I have determined the critical scales for accurately capturing baseline isotopic variation in ecologically important autotrophic and consumer taxa (e.g. macroalgae, particulate organic matter and suspension and grazing consumers), and then related isotopic variation in macroalgae to properties of their surrounding physical and biogeochemical environment. I have then used these relationships to project and forecast baseline values in space and time. Lastly, I have tested the suitability of different primary consumers, representing suspension and grazing functional groups to capture spatial and temporal isotopic variation of their respective diets, to act as invariable proxies of δ13C and δ15N baselines.
Isotopic variability of basal resources differed between autotrophs and consumers, and among species within these groups, and between isotopes (i.e. δ13C and δ15N), demonstrating the difficulty in capturing accurate and representative values. Spatial patterns for the δ13C and δ15N in the kelp Ecklonia radiata, the δ15N in the calcareous red alga Amphiroa anceps, and the δ13C in the ascidian Herdmania momus and the bivalve Septifer bilocularis, were influenced by variation at replicates (10s of m) and sites (1s of km) over regions (10s of km). Whereas, the reverse was true for δ13C and δ15N in the foliose red alga Plocamium preissianum, δ15N in S. bilocularis, and δ13C in the gastropod Turbo torquatus, with regional differences being the greatest source of influence. Temporally, patterns of δ13C and δ15N variation in each taxon and trophic group were more comparable, with seasonal variation eliciting a weak or negligible effect, but monthly variation often resulting in a strong effect.
Temperature, light, water motion, and measurements of dissolved inorganic carbon, nitrogen and phosphorous correlated with spatial and temporal variation in the stable isotopes of macroalgae, but these relationships varied with taxa and isotope. Surprisingly, water temperature was the best single explanatory variable, accounting for ~50-60% of variation in the δ13C and δ15N of P. preissianum, and the δ15N of E. radiata and A. anceps. From the above relationships, spatial predictions of δ13C and δ15N values in macroalgae showed clear latitudinal patterns, which covered a far wider range of values than temporal predictions, over a 12-month period. This illustrates the potential scale in the shift of isotopic baseline food sources over broad scales, and its implications for food web studies.
Primary consumers, particularly the bivalve Septifer bilocularis and the gastropod Turbo torquatus, generally mitigated a large proportion of the autotrophic δ15N variation and displayed relatively stable δ15N over time, and appeared to time-integrate the δ15N of their diet. Further, by conducting a controlled feeding study, I showed that S. bilocularis exhibited slow δ15N turnover estimates (e.g. half-life of 56 days), which from simulations, negated and “dampened” the effect of fluctuating δ15N values of food sources. This suggests that, owing to their high abundances and wide distributions, these species can be used to compare δ15N baselines over large spatial scales. However, this was not the case for δ13C, where primary consumers were as variable as those autotroph(s) they are assumed to proxy. Therefore, consistency in consumer δ15N does not necessarily equate to consistency in δ13C.
The fact that different autotrophs and consumers elicit different patterns of variation, show that sampling designs need to be compatible to the research questions of interest. Otherwise, improper allocation of sampling effort may decrease the probability of detecting ecologically important differences. Consequently, my results provide a reference from which to determine the appropriate sampling design to capture variation in ecologically important taxa, to help inform future studies. Further, the models I have developed to predict isotopic values for important autotrophic sources, and the identification of reference taxa of baseline δ15N (bivalves and gastropods), could be used by ecologists to remove a large proportion of unexplained variation, thus facilitate the interpretation of variation in stable isotopes of consumers in food webs, to help answer important questions in food web ecology.
8
"Ecosystem Impacts of Consumer Evolution: Intraspecific Variation in the Elemental Phenotype of Aquatic Consumers." Doctoral diss., 2017. http://hdl.handle.net/2286/R.I.42054.
Full textAbstract:
abstract: Primary production in aquatic ecosystems is often limited by the availability of nitrogen (N) and/or phosphorus (P). Animals can substantially alter the relative availability of these nutrients by storing and recycling them in differential ratios. Variation in these stoichiometric traits, i.e., the elemental phenotype, within a species can link organismal evolution to ecosystem function. I examined the drivers of intraspecific variation in the elemental phenotype of aquatic consumers to test for the generality of these effects. Over a thermal gradient in Panamá, I found that average specific growth grate and body P content of the mayfly Thraulodes increased with environmental temperature, but that these patterns were due to site-specific differences rather than the direct effects of warmer temperature. In a meta-analysis of published studies, I found that in fishes intraspecific variation in dietary N:P ratio had a significant effect on excretion N:P ratio, but only when accounting for consumption. I tested for the effects of variation in consumption on excretion N:P ratio among populations of the fish Gambusia marshi in the Cuatro Ciénegas basin in Coahuila, Mexico. G. marshi inhabits warm groundwater-fed springs where it often co-occurs with predatory fishes and cool runoff-dominated wetlands which lack predators. Using stoichiometric models, I generated predictions for how variation in environmental temperature and predation pressure would affect the N:P ratio recycled by fishes. Adult female G. marshi excretion N:P ratio was higher in runoff-dominated sites, which was consistent with predators driving increased consumption rates by G. marshi. This result was supported by a diet ration manipulation experiment in which G. marshi raised on an ad libitum diet excreted N:P at a lower ratio than fish raised on a restricted diet ration. To further support the impacts of predation on phenotypic diversification in G. marshi, I examined how body morphology varied among habitats and among closely related species. Both among and within species, predation had stronger effects on morphology than the physical environment. Overall, these results suggest that predation, not temperature, has strong effects on these phenotypic traits of aquatic consumers which can alter their role in ecosystem nutrient cycling through variation in consumption rates.Dissertation/Thesis
Doctoral Dissertation Biology 2017
9
Tso, Hsiu-Lin, and 左繡藺. "The study of the preferences on aquatic products, consciousness, and acceptance of Taipei city consumers towards TGAP certified certification system." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/45909328967607530200.
Full textAbstract:
碩士國立臺灣海洋大學
水產養殖學系
100
Nowadays, food safety of aquatic products is very important. In recent years, peoples pay more attentions on the food and the quality of food. The requirement of safety and the quality of the aquatic products gradually increases. Taiwan in many countries has been officially joined to the World Trade Organization (WTO) since January 1, 2002. Good Aquaculture Practice (GAP) was initiated by the Taiwan government in 2004 until 2006. In order to meet the requirements in international trends in future time, GAP was changed to Taiwan Good Aquaculture Practice (TGAP) in 2007. Besides, government aimed to fully implement the traceability system on aquatic products in 2015. Although the traceability system has been promoted for many years, however this ‘traceability system’ is still at unbalance stage. Therefore, the objectives were to study the preferences, consciousness, and acceptance of consumers towards TGAP certified aquatic products and investigate the impacts of consumers when buying the TGAP certified aquatic products. Data was collected from the customers at the hypermarket in Taipei, Carrefour hypermarket. There was about 1212 of valid questionnaire obtained. Results showed that the understanding of customers on the TGAP aquatic products was low. Besides, most of them are concerned about the origin of the aquatic products. For the question that TGAP aquatic products are safe to eat, there was 68.79 % of customers never consuming the TGAP aquatic products and 54.56 % of customers have not seen the verified label of the TGAP aquatic products. Results showed that consumers accepted the prices of the TGAP aquatic products increased in the range of 3-10% and the marketing place for the TGAP aquatic products are hypermarkets and stores. Besides, marketing strategy can be emphasized by the inspection, the credibility of institution and the excellent product quality.
10
HSU, MENG-HSIN, and 許夢馨. "The Impact of Consumers’ Attitude, Subjective Norms, Perceived Behavioral Control, and Environmental Consciousness on Purchasing Intentions and Behavior of Green Aquatic Products." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/t9fdce.
Full textAbstract:
碩士長榮大學
管理學院經營管理碩士班
107
Overfishing and consuming has brought about the depletion of marine resources in recent years. With the destructive pollution caused by industrialization and urbanization, the increasing of environmental consciousness has begun attracting public attention to the importance of sustainable development. Motivations and intentions of purchasing products are different from the past that consumers start to use green products for the sake of the environment. Therefore, issues on intentions and action of purchasing green aquatic products are worthy to study. The theory of planned behavior (TPB), which includes personal attitude, subjective norms, and perceived behavioral control, is commonly used in predicting human behavior. The TPB, together with environmental knowledge and concerns are generally considered critical to influence consumers’ purchasing intentions and behavior; however, there is little research on purchasing intentions and behavior of green aquatic products. This study accordingly takes individuals with fixed monthly income in Taiwan as research subjects, and uses questionnaires to explore the impact of consumers’ attitude, subjective norms, perceived behavioral control, and environmental consciousness on purchasing intentions and behavior of green aquatic products. Research findings indicate that consumers’ attitude, subjective norms, environmental concern, and environmental knowledge have positive and significant impacts on purchasing intentions of green aquatic products. Consumers’ purchasing intentions also have a significant influence on purchasing behavior of green aquatic products. Keywords: The Theory of Planned Behavior, Environmental Consciousness, Purchasing Intentions, Purchasing Behavior, Green Aquatic Products.
Books on the topic "Aquatic consumers"
1
Office, Canada Environment Canada National Guidelines and Standards. Canadian tissue residue guidelines for the protection of consumers of aquatic life: Methylmercury. Ottawa: The Office, 2001.
Find full text
2
Canada. National Guidelines and Standards Office. Canadian tissue residue guidelines for the protection of consumers of aquatic life: Methylmercury. Ottawa, Ont: National Guidelines and Standards Office, 2002.
Find full text
3
Canadian Council of Ministers of the Environment. Water Quality Guidelines Task Group. Protocol for the derivation of Canadian tissue residue guidelines for the protection of wildlife that consume aquatic biota. Winnipeg: The Group, 1997.
Find full text
4
Evaluation of waterpark use: An examination of active-visitors and passive-visitors by importance-performance analysis. 1989.
Find full text
5
Evaluation of waterpark use: An examination of active-visitors and passive-visitors by importance-performance analysis. 1989.
Find full text
6
Evaluation of waterpark use: An examination of active-visitors and passive-visitors by importance-performance analysis. 1989.
Find full text
7
Evaluation of waterpark use: An examination of active-visitors and passive-visitors by importance-performance analysis. 1987.
Find full text
8
Hoeger, Werner W. K., and Terry-Ann Spitzer. Physical Fitness: The Water Aerobics Way. Morton Publishing Company, 1990.
Find full text
9
Pikaar, Ilje, Jeremy Guest, Ramon Ganigué, Paul Jensen, Korneel Rabaey, Thomas Seviour, John Trimmer, Olaf van der Kolk, Céline Vaneeckhaute, and Willy Verstraete, eds. Resource Recovery from Water. IWA Publishing, 2022. http://dx.doi.org/10.2166/9781780409566.
Full textAbstract:
Abstract Throughout history, the first and foremost role of urban water management has been the protection of human health and the local aquatic environment. To this end, the practice of (waste-)water treatment has maintained a central focus on the removal of pollutants through dissipative pathways. Approaches like – in the case of wastewater treatment – the activated sludge process, which makes ‘hazardous things’ disappear, have benefitted our society tremendously by safeguarding human and environmental health. While conventional (waste-)water treatment is regarded as one of the greatest engineering achievements of the 20th century, these dissipative approaches will not suffice in the 21st century as we enter the era of the circular economy. A key challenge for the future of urban water management is the need to re-envision the role of water infrastructure, still holding paramount the safeguard of human and environmental health while also becoming a more proactive force for sustainable development through the recovery of resources embedded in urban water. This book aims (i) to explain the basic principles governing resource recovery from water (how much is there, really); (ii) to provide a comprehensive overview and critical assessment of the established and emerging technologies for resource recovery from water; and (iii) to put resource recovery from water in a legal, economic (including the economy of scale of recovered products), social (consumer's point of view), and environmental sustainability framework. This book serves as a powerful teaching tool at the graduate entry master level with an aim to help develop the next generation of engineers and experts and is also highly relevant for seasoned water professionals and practicing engineers. ISBN: 9781789060317 (Paperback) ISBN: 9781780409566 (eBook)
Book chapters on the topic "Aquatic consumers"
1
Schulz, Ralf, and Mirco Bundschuh. "Pathways of Contaminant Transport Across the Aquatic-Terrestrial Interface: Implications for Terrestrial Consumers, Ecosystems, and Management." In Contaminants and Ecological Subsidies, 35–57. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-49480-3_3.
Full text
2
Garrido Gamarro, Esther, and Violetta Costanzo. "Dietary Exposure to Additives and Sorbed Contaminants from Ingested Microplastic Particles Through the Consumption of Fisheries and Aquaculture Products." In Microplastic in the Environment: Pattern and Process, 261–310. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-78627-4_8.
Full textAbstract:
AbstractMicroplastics and nanoplastics may be found in the gastrointestinal tract of some aquatic animals and could potentially be ingested by humans if consumed whole. Information on the toxicity of plastic particles, as well as co-contaminants such as plastic additives, remains scarce. This represents a serious challenge to perform realistic risk assessments. An exposure assessment of selected plastic additives and co-contaminants of known toxicity associated with microplastics was carried out for shellfish in this study, which builds on an exposure assessment of microplastic additives and a limited number of associated contaminants in mussels conducted by the FAO in 2017. This study evaluates possible impacts to food safety by examining a diverse additives and associated sorbed contaminants. The results suggest that the levels of certain microplastic additives and sorbed co-contaminants in target animals (shrimp, prawns, clams, oysters, and mussels) do not pose a food safety threat to consumers. To get to further conclusions, an exposure assessment from the whole diet should be carried out and the toxicity of some of the most common polymers and plastic additives, as well as their mixtures, needs to be carefully evaluated.
3
Rojo, Carmen, and Guillem Salazar. "Why are there so many kinds of planktonic consumers? The answer lies in the allometric diet breadth." In Fifty years after the ‘‘Homage to Santa Rosalia’’: Old and new paradigms on biodiversity in aquatic ecosystems, 91–102. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-9908-2_8.
Full text
4
Mondragón-Camarillo, Laura, and Salvador Rodríguez Zaragoza. "Food Webs." In Plankton Communities [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.97252.
Full textAbstract:
Ciliates are important elements of the trophic networks of aquatic and terrestrial environments, they can be primary producers (myxotrophs), consumers of bacteria, algae, flagellates, even other ciliates and can serve as food for metazoans, for all the above they are the link between different levels of food webs. The structure of the ciliates varies according to the seasons of the year and depending on the trophic conditions of the aquatic systems. Ciliated communities have modifications and adaptations in response to environmental perturbations. The objective of this chapter is to describe the importance of different trophic groups of ciliates in different ecosystems, including anthropogenic perturbations and their impact on trophic webs.
5
Ceyda Irkin, Latife. "The Effects of Shellfish Consumption Frequency for Human Health." In Update on Malacology. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.100405.
Full textAbstract:
Depending on the world population, the importance of water resources and the consumption of aquatic organisms as a food source are increasing day by day. The presence of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are involved in critically important biochemical and physiological processes in the body, emphasizes the importance of seafood consumption. Shellfish are low in calories but rich in protein and omega-3 fatty acids. They also contain high amounts of many micronutrients, including iron, zinc, magnesium and B12. Consuming shellfish regularly can boost immunity, aid weight loss, and support brain and heart health. However, shellfish is one of the common food allergens, and some species may contain contaminants and heavy metals. Aquatic products poisoning occurs with the consumption of unhealthy seafood or fish containing toxins. Symptoms cause severe and fatal poisoning in consumers, depending on the presence and concentration of the toxin. To prevent food poisoning, information on the growing conditions of the species should be provided and regularly inspected for toxins (heavy metal poisoning and allergic reactions).
6
"Hudson River Fishes and their Environment." In Hudson River Fishes and their Environment, edited by Nina F. Caraco and Jonathan J. Cole. American Fisheries Society, 2006. http://dx.doi.org/10.47886/9781888569827.ch5.
Full textAbstract:
<em>Abstract.—</em>Organic material can enter aquatic systems by de novo gross primary production (GPP) from inorganic carbon within the system (autochthonous sources) or by import from the surrounding watershed and upstream aquatic systems (allochthonous sources). We analyzed the spatio–temporal variation in these two organic carbon sources for the 150-km long tidal freshwater Hudson during 2 years (1999 and 2000). Gross primary production was calculated from dawn– dusk sampling at 2-km intervals over the length of the Estuary for dissolved oxygen, pH, and DIC. Allochthonous inputs (All) were also calculated for the same periods based on organic carbon measurements and hydrologic flows. The relative importance of these two organic carbon sources (GPP/All) varied by over 30-fold across space and time. This variation was related to hydrologic inputs; on average 1999 (the second driest summer in the past 15 years) had 10- fold greater GPP/All than did 2000 (the wettest summer in 15 years). Associated with the high GPP/All in 2000 there was higher carbon dioxide supersaturation and net heterotrophy as compared to 1999. We suggest that hydrologically driven variation in GPP/All may also impact the food web and the dominant organic carbon source for fish and invertebrate consumers in the river. Natural abundance <sup>14</sup>C measurements could potentially trace these two food sources as they vary in space and time.
7
"Hudson River Fishes and their Environment." In Hudson River Fishes and their Environment, edited by Nina F. Caraco and Jonathan J. Cole. American Fisheries Society, 2006. http://dx.doi.org/10.47886/9781888569827.ch5.
Full textAbstract:
<em>Abstract.—</em>Organic material can enter aquatic systems by de novo gross primary production (GPP) from inorganic carbon within the system (autochthonous sources) or by import from the surrounding watershed and upstream aquatic systems (allochthonous sources). We analyzed the spatio–temporal variation in these two organic carbon sources for the 150-km long tidal freshwater Hudson during 2 years (1999 and 2000). Gross primary production was calculated from dawn– dusk sampling at 2-km intervals over the length of the Estuary for dissolved oxygen, pH, and DIC. Allochthonous inputs (All) were also calculated for the same periods based on organic carbon measurements and hydrologic flows. The relative importance of these two organic carbon sources (GPP/All) varied by over 30-fold across space and time. This variation was related to hydrologic inputs; on average 1999 (the second driest summer in the past 15 years) had 10- fold greater GPP/All than did 2000 (the wettest summer in 15 years). Associated with the high GPP/All in 2000 there was higher carbon dioxide supersaturation and net heterotrophy as compared to 1999. We suggest that hydrologically driven variation in GPP/All may also impact the food web and the dominant organic carbon source for fish and invertebrate consumers in the river. Natural abundance <sup>14</sup>C measurements could potentially trace these two food sources as they vary in space and time.
8
Agrawal, Bipin Jagdishprasad. "Prospective Sustainability of Utilization of Effective Techniques for Remediation of Heavy Metals From Textile Effluents." In Biostimulation Remediation Technologies for Groundwater Contaminants, 19–49. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-4162-2.ch002.
Full textAbstract:
Textile industries are one of the prevalent water consumers and contaminators ensuing high generation of waste water. Wastewater from dyeing and printing units is often rich in organic compounds, colours, and heavy metals containing residues of various dyes and chemicals. Among these waste water pollutants, heavy metals are of serious environmental concern in recent years. Metals are extensively used for manufacture of synthetic dyestuffs and for colouration of natural dyes on textiles to achieve different shades and hues. Heavy metals such as lead (Pb), chromium (Cr), cadmium (Cd), iron (Fe), zinc (Zn), copper (Cu), etc. are widely used for production of colour pigments of textile dyes. These heavy metals, highly toxic, get conveyed to the environment, and can bio-accumulate in the human body, aquatic life, natural water-bodies, and also possibly become trapped in the soil. The chapter deals with the utilization of heavy metals in textile wet processing, their important characteristics, various toxic aspects, and different methods for their elimination from the textile effluent liquors.
9
Agrawal, Bipin Jagdishprasad. "Prospective Sustainability of Utilization of Effective Techniques for Remediation of Heavy Metals From Textile Effluents." In Research Anthology on Emerging Techniques in Environmental Remediation, 517–42. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-6684-3714-8.ch028.
Full textAbstract:
Textile industries are one of the prevalent water consumers and contaminators ensuing high generation of waste water. Wastewater from dyeing and printing units is often rich in organic compounds, colours, and heavy metals containing residues of various dyes and chemicals. Among these waste water pollutants, heavy metals are of serious environmental concern in recent years. Metals are extensively used for manufacture of synthetic dyestuffs and for colouration of natural dyes on textiles to achieve different shades and hues. Heavy metals such as lead (Pb), chromium (Cr), cadmium (Cd), iron (Fe), zinc (Zn), copper (Cu), etc. are widely used for production of colour pigments of textile dyes. These heavy metals, highly toxic, get conveyed to the environment, and can bio-accumulate in the human body, aquatic life, natural water-bodies, and also possibly become trapped in the soil. The chapter deals with the utilization of heavy metals in textile wet processing, their important characteristics, various toxic aspects, and different methods for their elimination from the textile effluent liquors.
10
Kültz, Dietmar. "Aquaculture systems as mesocosms." In A Primer of Ecological Aquaculture, 45–54. Oxford University PressOxford, 2022. http://dx.doi.org/10.1093/oso/9780198850229.003.0004.
Full textAbstract:
Abstract The boundary between aquaculture and capture fisheries is becoming blurred as wild populations of aquatic organisms are ever more impacted (unintended) and managed (intended) by humans who have irreversibly changed the trajectory of the biosphere. Most current aquaculture systems are semi-intensive, open systems that depend to a very high degree on natural ecosystem services. A mismatch between a significant human-induced decline of natural ecosystems on the one hand and increased human demand for ecosystem services on the other hand calls for solutions that minimize the reliance on ecosystem services for all purposes, including aquaculture. Low-yield, extensive aquaculture systems are sustainable in suitable areas, but they are not economical on a global scale unless the human population declines significantly. The most ecologically sustainable aquaculture systems for a growing human population are intensive, closed recirculating aquaculture systems (RAS), which are human-managed mesocosms that require constant balancing of energy and matter in inputs and outputs. Knowledge generated and technologies developed for culture of ornamental organisms in aquaria at microcosm scale have advanced ecologically sustainable aquaculture at larger mesocosm scales. Ecosystem succession must be managed when establishing aquaculture mesocosms to maintain optimal conditions for growth, health, and development of aquaculture organisms. Since trophic level transfer efficiency (TLTE) is only 10–20%, aquaculture systems for top-level carnivores are least energetically efficient and most resource intensive. Balancing trophic levels in closed aquaculture mesocosms requires proportional matching of primary producers, consumers, and decomposers to minimize reliance on ecosystem services.
Conference papers on the topic "Aquatic consumers"
1
Takhteev, V. V., D. A. Batranin, I. O. Eropova, E. B. Govorukhina, and S. I. Didorenko. "NIGHT MIGRATION COMPLEX OF ENDEMIC AMFIPOD AS AN INDICATOR OF ENVIRONMENTAL STATE BAIKAL LAKE." In V International Scientific Conference CONCEPTUAL AND APPLIED ASPECTS OF INVERTEBRATE SCIENTIFIC RESEARCH AND BIOLOGICAL EDUCATION. Tomsk State University Press, 2020. http://dx.doi.org/10.17223/978-5-94621-931-0-2020-37.
Full textAbstract:
With the ongoing anthropogenic eutrophication of the Lake Baikal there is an increase in the abundance not only of aquatic vegetation, but also organismsconsumers. As consumers of vegetable detritus are crustaceans – amphipods, which, by eating detritus, partially reduce the pollution of the lake with rotting organic matter. A significant increase in their number is evidenced by the increase in the abundance of amphipods in the nocturnal migratory complex in the coastal pelagic zone.
2
PARASKA, O. "The Assessment of the Environmental Impact of Textile Cleaning Processes in the Aquatic Environment on Human Health." In Terotechnology XII. Materials Research Forum LLC, 2022. http://dx.doi.org/10.21741/9781644902059-44.
Full textAbstract:
Abstract. This article analyzes the technological process of textile product cleaning in the aquatic environment from the point of view of identified sources of hazard. It is established at what particular stages of cleaning of the products, the negative affects on the environment, workers and consumers occur. According to Life Cycle Assessment (LCA), detailed information was received at an enterprise about the technological processes and the impact of their individual factors on the environment and human health. Creating closed water cycles will reduce the impact on the environment and human health. The use of new types of biosurfactants in detergent compositions will allow reducing the duration of technological operations, and the number of cycles of textile product processing, to increase their exploitation life and improve the quality of textile product cleaning.
3
Law, Karen H., Michael J. Chan, and Michael D. Jackson. "Societal Costs of Transportation Fuels: Enabling a True Comparison of Alternatives to Conventional Fuels." In ASME 2012 6th International Conference on Energy Sustainability collocated with the ASME 2012 10th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/es2012-91465.
Full textAbstract:
Petroleum-based conventional fuels dominate the transportation sector due to simple economics. Per unit of energy, few fuels can rival gasoline and diesel in terms of total cost of ownership to the consumer. While some fuels, such as natural gas and electricity, offer lower fuel costs and/or higher vehicle efficiencies than conventional fuels, the fuel price differentials may not be sufficient to offset the higher initial costs of the vehicles, especially if petroleum prices are low. Even when total costs of ownership are similar or slightly lower for alternative fuels than conventional fuels, differences in attributes, such as vehicle range, fueling time, cargo space, vehicle availability, and fuel availability, and consumer loss aversion suggest that more substantial differences in costs are required before consumers are willing to adopt the alternatives. In order for the transportation sector to achieve greater energy sustainability, the traditional economic paradigm for the vehicle purchase decision must expand to incorporate the true benefits of alternatives to conventional fuels, namely the societal benefits of increased energy security, lower criteria pollutant emissions, and lower greenhouse gas emissions. These benefits are not purely economic and yet are crucial to the future of transportation. To capture these benefits in the economic scheme, the societal costs of transportation fuels to the U.S. have been monetized according to measurable impacts. For energy security, the costs are tied to decreased economic output, loss of national gross product, economic strain and volatility, oil supply shocks and price spikes, supply disruption, and import costs. For criteria pollutant and greenhouse gas emissions, the costs are tied to human health impacts, property damage, loss of agricultural productivity, and destruction of terrestrial and aquatic ecosystems. These societal costs then applied to the use of specific fuels in two representative market segments, representing distinct applications, duty cycles, fuel consumption, and vehicle lifetime. Incorporating the monetized societal costs of transportation fuels in the total costs of ownership enables a fair comparison that reflects the benefits of alternatives to conventional fuels. As a result, these societal costs provide a justifiable framework for a real discussion on incentives and the direction of energy policy, beyond the mere objective of low fuel prices that has pervaded policy discussions to date.
4
Tang, Zhongping, Peng Jin, Dingwei Sun, Shaoming Zhang, and Weimin Liu. "Investigation of Some Base Oil as Biodegradable Water-Cooling Two-Stroke Engine Oil." In ASME 2006 Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/ices2006-1328.
Full textAbstract:
According to statistics, a large portion of used lubricants remain as potential hazards for the environment. Particularly, about 30 to 50% lubricant used in outboard marine engines is not burned completely and released into the water. As a result, consumers demand environmentally compatible lubricants due to concern about loss of mineral oil-based lubricants to the environment which can result in water contamination and pose a threat to animal and plant life. To prevent bioaccumulation of these materials in aquatic plants and animals, many agencies are considering regulations toward to biodegradable two-stroke outboard marine engines oil. Vegetable oils and ester oils are very suitable to develop “green lubricants”. Ester oils usually show excellent high temperature stability, low temperature fluidity, high viscosity index, very low volatility, good miscibility and biodegradability, but they are expensive and also produce many poisonous materials to environmental during produce process. Vegetable oils are biodegradable, nontoxic and renewable, moreover, their cost is reasonable compared to ester oils. Accordingly, vegetable oils are considered as potential candidates to replace conventional mineral oil-based lubricating oils, but the poor oxidative stability limits their utilization in large scale. Investigation of this work have found that proper percentage rapeseed oil can meet the requirements of biodegradable water-cooling two stroke engine oil, futhermore this two-cycle engine oil has good miscibility without need any miscibility-enhancing solvents. Research results indicate that two-cycle engine oil, which comprised rapeseed oil, ester oil and low viscosity hydrocracked oil as well as functional additives, exhibits good oxidative stability, easy biodegradability and good miscibility.
5
Gong, Seunghun, Amarnathvarma Angani, and Kyoo Jae Shin. "Realization of Fluid Flow Control System for Vertical Recycling Aquatic System (VRAS)." In 2018 International Symposium on Computer, Consumer and Control (IS3C). IEEE, 2018. http://dx.doi.org/10.1109/is3c.2018.00054.
Full text
6
Wang, Dennis, Rachel Kuhr, Kristen Kaufman, Richard Crawford, Kristin L. Wood, and Dan Jensen. "Empirical Analysis of Transformers in the Development of a Storyboarding Methodology." In ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/detc2009-87420.
Full textAbstract:
Transforming products, or more generally transformers, are devices that change state in order to facilitate new, or enhance an existing, functionality. Mechanical transformers relate to products that reconfigure and can be advantageous by providing multiple functions, while often conserving space. A basic example is a foldable chair that can be stowed when not in use, but provides ergonomic and structural seating when deployed. Utilizing transformation can also lead to novel designs that combine functions across domains, such as an amphibious vehicle that provides both terrestrial and aquatic transportation. In order to harness these assets of transformation, the Transformational Design Theory [1] was developed. This theory outlines a set of principles and facilitators that describe and embody transformation for the purpose of systematically assisting the design of transformers. To build on this theory, this paper analyzes a repository of popular transformer toys. Transformer toys are chosen for this study because of their richness in displaying a variety of kinematic aspects of transformation. Through this process, new definitions to describe transformation are garnered and a set of guidelines are developed to further aid designers. The empirical data set of transformer toys is rich in information and provides a basis for application to other fields, such as robotics and consumer products. These insights, in conjunction with the use of storyboarding, create a new method of designing transformers. This paper presents the method and concludes with a validation exercise in the creation of a new transformer toy.
7
Twomey, Kelly M., Ashlynn S. Stillwell, and Michael E. Webber. "The Water Quality and Energy Impacts of Biofuels." In ASME 2009 3rd International Conference on Energy Sustainability collocated with the Heat Transfer and InterPACK09 Conferences. ASMEDC, 2009. http://dx.doi.org/10.1115/es2009-90294.
Full textAbstract:
Concerns over rising fuel prices, national security, and the environment have led to the Energy Independence and Security Act (EISA) of 2007, which established a mandate for the production of at least 36 billion gallons of biofuels in 2022, up to 15 billion gallons of which can come from traditional first-generation biofuels sources such as corn starch-based ethanol. One consequence of ramped-up biofuels production is the risk of additional soil runoff. This runoff, potentially laden with nitrogen and phosphorus compounds from fertilizers, can detrimentally impact water quality. Consequently, the water treatment sector might require additional energy to remove increased quantities of sediment and run-off from nutrients and pesticides in degraded water bodies downstream of agricultural land. At the same time, the cumulative effects of increased eutrophication in the Mississippi and Atchafalaya River Basins have already negatively impacted much of the aquatic life in the Louisiana-Texas continental shelf. A recent report by U.S. Geological Survey measured nitrogen loading in the Mississippi River basin as high as 7,761 metric tons per day, the highest recorded loading in the past three decades, 52% of which is attributed to loading from corn and soybean crops. Massive algae blooms that thrive in nutrient-rich water deplete the water of oxygen when they die, creating a hypoxic region. This hypoxic region, which currently covers a region the size of New Jersey, is considered to be the second-largest dead zone in the world as of 2007. As a result, the Gulf Hypoxia Action Plan of 2008 was established to reduce nitrogen and phosphorous loading by 45% in order to shrink the hypoxic region to 5,000 square kilometers. Thus, at a time when water quality priorities aim to decrease nitrogen and phosphorous loading in waterways, legislative targets are seeking to increase corn starch-based ethanol production to 15 billion gallons a year, and thereby potentially increase nitrogen loading in this region by 10–34% due to runoff. Consequently, the energy intensity for water treatment may have a two-fold challenge. Because water and wastewater treatment is already responsible for 4% of the nation’s electricity consumption, putting more stringent demands on this sector could put upward pressure on energy consumption. This analysis quantifies the impact that the mandated increase in ethanol production might have on the energy required for water treatment in the United States. It reports results from a first-order top-level analysis of the energy impacts of ethanol. The results indicate that the increased production corn-starch based ethanol in the United States is not likely to increase the energy consumed during surface water treatment, but might cause significant increases in the energy consumed during groundwater treatment.
8
Radulescu, Victorita. "Autonomous Platform Collecting the Vegetation in Excess From Natural Reservations Lakes Used As a Future Biomass Resource." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-70331.
Full textAbstract:
In Romania, near the Black Sea are two Natural Reservations lakes with salt water, Techirghiol, and Mangalia nowadays confronted with new environmental issues. Lake never freezes. Under these conditions, there are always birds in transit or in wintering; some of them protected species as endangered. There are no known or available solutions at present that can be used here, without disturbing the biological balance. This paper presents a prototype, patent pending in Romania, which has achieved significant results in protection of the natural environment. The prototype is an autonomous pilot station, placed on a mobile pontoon, powered by photovoltaic panels. It can collect and partially dry the aquatic vegetation developed in excess due to eutrophication. The harvested vegetation is used as the biomass resource to warm the Research Centre on shore, the greenhouse for the protected plant species and the poultry incubator. The prototype now is implemented in Techirghiol Lake as to diminish the local environmental problems: the massive mass of vegetation, the invasive species that appeared, as the invertebrates, the interference scallops, and the predator fish. Due to the permanent decreasing the number of the specific fish, all bird colonies are affected. The proposed solution is innovative, perfect ecological and energetic independent. The mobile pontoon is commanded from distance. The solar panels ensure the pontoon movement and the supply of the collecting, compacting, and partially drying the vegetation. The detailed functioning of the prototype is further detailed presented. The main advantage of this solution is that the vegetation can be collected during the entire period of vegetation without disturbing the biologic environmental, nests period of construction, laying eggs, rearing birds, etc. A second major advantage is that the extracted vegetation can be consumed immediately and integrally into a biomass power plant. The third advantage of this technology is that the platform is placed on a mobile pontoon energetically independent, entirely automated and with a constant adaptation of the operating parameters in accordance with climatic conditions. This innovative solution is accordance to the Romanian reply for EU Council Directives, UE EUCO 75/13 CO EUR 7 signed in Brussels at 22/05/2013, referring to the promotion of the new solutions based on utilization of renewable technology with environmental effects. The prototype has a multi- and a cross-disciplinary character due to the main components. It represents a powerful applicative research requested and co-financed by the National Authorities and the private sector, as to solve this problem appeared into these Natural Reservations.
Reports on the topic "Aquatic consumers"
1
Walker, David, Craig Baker-Austin, Andy Smith, Karen Thorpe, Adil Bakir, Tamara Galloway, Sharron Ganther, et al. A critical review of microbiological colonisation of nano- and microplastics (NMP) and their significance to the food chain. Food Standards Agency, April 2022. http://dx.doi.org/10.46756/sci.fsa.xdx112.
Full textAbstract:
Microplastics are extremely small mixed shaped plastic debris in the environment. These plastics are manufactured (primary microplastics) or formed from the breakdown of larger plastics once they enter the terrestrial, freshwater and marine environments (secondary microplastics). Over time, a combination of physical, photochemical and biological processes can reduce the structural integrity of plastic debris to produce microplastics and even further to produce nanoplastics. NMPs have been detected in both the aquatic and terrestrial environments and can be easily spread by water, soil and air and can be ingested by a wide range of organisms. For example, NMPs have been found in the guts of fish and bivalve shellfish. Microplastics have also been detected in food and in human faeces. Therefore, NMPs are not only found in the environment, but they may contaminate the food supply chain and be ingested by consumers. There is evidence suggesting that microorganisms are able to colonise the surfaces of microplastics and aggregates of nanoplastics. However, the risk to consumers posed by NMPs colonised with microorganisms (including those that are AMR) which enter the food supply chain is currently unknown.
2
Geisthardt, Eric, Burton Suedel, and John Janssen. Monitoring the Milwaukee Harbor breakwater : an Engineering With Nature® (EWN®) demonstration project. Engineer Research and Development Center (U.S.), March 2021. http://dx.doi.org/10.21079/11681/40022.
Full textAbstract:
The US Army Corps of Engineers (USACE) maintains breakwaters in Milwaukee Harbor. USACE’s Engineering With Nature® (EWN®) breakwater demonstration project created rocky aquatic habitat with cobbles (10–20 cm) covering boulders (6–8 metric tons) along a 152 m section. A prolific population of Hemimysis anomala, an introduced Pontocaspian mysid and important food source for local pelagic fishes, was significantly (p < .05) more abundant on cobbles versus boulders. Food-habits data of alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) provided evidence that H. anomala were a common prey item. Night surveys and gill netting confirmed O. mordax preferred foraging on the cobbles (p < .05) and consumed more H. anomala than at the reference site (p < .05). H. anomala comprised a significant portion of the diets of young-of-the-year (YOY) yellow perch (Perca flavescens), YOY largemouth bass (Micropterus salmoides), and juvenile rock bass (Ambloplites rupestris) caught on the breakwater. The natural features’ construction on the breakwater increased the available habitat for this benthopelagic macroinvertebrate and created a novel ecosystem benefiting forage fish and a nursery habitat benefiting nearshore game fish juveniles. These data will encourage the application of EWN concepts during structural repairs at other built navigation infrastructure.