Download or read book Impact of Copper Pollutants and Environmental Factors on Predator prey Interactions in Marine Food Chains written by Christopher Kent Kwan and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Predators scare and eat prey, and the consequences of predators on community structure and ecosystem function depend largely on the relative importance of these two activities. An increasing trend in recent ecological research is a focus on fear, the predator non-consumptive effects on prey. A single predator may scare off many more prey than it can eat, especially if many prey individuals can detect it from far away. Predator non-consumptive effects often alter prey physiology, behavior, and morphology. These effects may translate into changes in community structure and ecosystem function. Although there is an emerging appreciation for the context-dependency of these interactions, we lack an understanding about how these interactions change with increasing anthropogenic stress--particularly chemical pollution. The prevalence of chemical pollution in coastal habitats combined with its potential to disrupt predator-prey interactions suggest that we must better understand how these stressors impact species interactions and in turn, ecosystem function. The consequences of sublethal pollutant levels on a single species may manifest themselves throughout the community. I addressed these issues by conducting laboratory and field experiments studying the impacts of sub-lethal copper levels and environmental factors on the species interactions in marine food chains. In Chapter 1, I tested the influence of chemical pollutants on predator-prey interactions because recent evidence suggests that pollutants may shift the role of consumptive and non-consumptive effects of predators. However, this hypothesis has not been tested directly by comparing predator consumptive and non-consumptive effects in polluted versus non-polluted settings. I used laboratory mesocosms to examine the influence of elevated copper pollution on the effects of crab predators in an estuarine food chain with intermediate whelk prey and basal barnacle resources. I examined predator consumptive effects (prey culled without predator chemical cues), non-consumptive effects (prey not culled and received predator chemical cues), and total effects (prey culled and received predator chemical cues). Although copper switched the relative importance of these effect types, the nature of this switch contrasted with our original prediction. Rather than decreasing whelk response to predator cues, copper compromised whelk responses to changes in conspecific density caused by simulated lethal predation. Specifically, reductions in conspecific density occurring in elevated copper levels did not trigger the normal increase in whelk consumption rates. Because intermediate copper concentrations did not change the effects of fear, these data suggest that copper decreased the relative importance of predator consumptive effects. However, this shift was not apparent at extremely high copper levels where non-consumptive effects also diminished. Given the prevalence of conspecific interactions among prey, disruption of these interactions at sublethal pollution levels may commonly influence predator impacts on their communities. In Chapter 2, I examined the extent to which pollutant effects are generalizable across food chains, since the increase of these anthropogenic stressors poses immense threats to the marine environment. Recent work indicates sublethal pollutant levels change organism behavior and species interactions. However, we have limited understanding of these pollutant impacts in terms of how long these effects last and whether different organisms are affected in similar ways. To address these gaps, I studied copper pollutant effects on the species interactions of two different marine food chains for extended durations. Both food chains consisted of predatory crabs, whelks, and barnacles. I examined the long-term impact of copper pollution on crab non-consumptive effects on whelk consumption of barnacles. For both food chains, in the absence of copper, crab cues induced predator avoidance behaviors in whelks and reduced their consumption on barnacles. In the food chain consisting of whelks from the open coast with lower exposure to pollutants, there were no effects of copper on whelks. For the food chain consisting of whelks from enclosed estuaries with greater exposure to pollutants, copper influenced whelk responses to crabs initially by increasing whelk consumption during exposure to crab cues. But this antagonistic effect between copper and crab cues on whelks attenuated after two weeks. My results show chemical contaminants may impact food chains differently, perhaps due to the evolutionary history of the component species, or their prior exposure to pollutants. In Chapter 3, I investigated the context-dependency of predator non-consumptive effects in the field, in light of the growing awareness that species interactions can be highly dependent on the environmental conditions in which they occur. The strength and direction of these interactions are often impacted by abiotic factors and human-caused stressors. However, there have been few studies conducted in the field to examine the influence of these variables on predator non-consumptive effects on prey. I conducted two field experiments investigating whether environmental conditions influence the strength of predator-non-consumptive effects in two different food chains. I tested the influence of ambient conditions on the non-consumptive effects of predatory crabs on whelk prey, which in turn feed on a basal resource of barnacles. I conducted a field experiment in San Francisco Bay to investigate whether differences in abiotic factors and pollutant levels among three sites would influence predator non-consumptive effects of crabs on their invasive whelk prey which feeds on barnacles. My data suggest the strength of predator non-consumptive effects varied among San Francisco Bay sites. Specifically, crab cues reduced whelk consumption of barnacles at two sites but did not have an effect at a third site. I found slightly warmer water at this one site, which may have weakened the predation risk caused by crab cues. Although whelks at this warmer site consumed more barnacles, they had a low growth efficiency that may be due to the higher metabolic demands of coping with warmer temperatures and relatively high pollution at this site. In another field experiment, I quantified the effects of predatory crab cues on whelk predation and growth rates at two sites in Bodega Harbor, CA. I found vastly different results between both Bodega Harbor sites. Namely, the presence of crabs lowered whelk consumption rates of barnacles at one site, but had no effect at the other site. Collectively, the results from all of our laboratory and field studies underscore the notion that predator-prey interactions are often context-dependent, and may especially be influenced by a highly variable, human-impacted environment. Understanding the relative effects of consumptive effects and non-consumptive effects in structuring ecological communities improves our abilities to predict and manage changes to species distributions in the face of anthropogenic stressors such as climate change, overfishing, species invasions, habitat alterations, and pollution. More specifically, a better understanding of how organisms affect each other and how those relationships are altered by a changing environment is critical in preparing and implementing conservation measures.

Download or read book Impact of Copper Pollutants and Environmental Factors on Predator prey Interactions in Marine Food Chain written by and published by . This book was released on 2015 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although the cascading impact of predators depends critically on the relative role of lethal predation and predation risk, we lack an understanding of how human-caused stressors may shift this balance. Emergent evidence suggests that pollution may increase the importance of predator consumptive effects by weakening the effects of fear perceived by prey. However, this oversimplification ignores the possibility that pollution may also alter predator consumptive effects. In particular, contaminants may impair the consumptive effects of predators by altering density-dependent interactions among prey conspecifics. No study has directly compared predator consumptive and non-consumptive effects in polluted versus non-polluted settings. We addressed this issue by using laboratory mesocosms to examine the impact of sublethal doses of copper on tri-trophic interactions among estuarine predator crabs Cancer productus, carnivorous whelk prey Urosalpinx cinerea, and the basal resource barnacles Balanus glandula. We investigated crab consumptive effects (whelks culled without crab chemical cues), non-consumptive effects (whelks not culled with crab chemical cues), and total effects (whelks culled with crab chemical cues) on whelks in copper polluted and non-polluted waters. Realistic copper concentrations suppressed the effects of simulated crab lethal predation (whelk culling) by removing density-dependent feeding by whelks. Specifically, reductions in conspecific density occurring in elevated copper levels did not trigger the normal increase in whelk consumption rates of barnacles. Weakened effects of fear were only observed at extremely high copper levels, suggesting consumptive effects were more sensitive to pollution. Thus, pollution may shape communities by altering the roles of predators and interactions among prey.

Download or read book Environmental Dependence of Non consumptive Effects in Predator prey Interactions written by Katrina A. Button and published by . This book was released on 2008 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ecology Abstracts written by and published by . This book was released on 1989 with total page 706 pages. Available in PDF, EPUB and Kindle. Book excerpt: Indexes journal articles in ecology and environmental science. Nearly 700 journals are indexed in full or in part, and the database indexes literature published from 1982 to the present. Coverage includes habitats, food chains, erosion, land reclamation, resource and ecosystems management, modeling, climate, water resources, soil, and pollution.

Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1986 with total page 732 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Microscale Testing in Aquatic Toxicology written by Peter G. Wells and published by CRC Press. This book was released on 2018-05-04 with total page 716 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bioassays are among the ecotoxicologist's most effective weapons in the evaluation of water quality and the assessment of ecological impacts of effluents, chemicals, discharges, and emissions on the aquatic environment. Information on these assessment aids is needed throughout the international scientific and environmental management community. This comprehensive reference provides an excellent overview of the small-scale aquatic bioassay techniques and applications currently in use around the world. This special volume is the result of several years of collaboration between Environment Canada and Fisheries and Oceans Canada. Internationally recognized research scientists at many institutions have contributed to this state-of-the-art examination of the exciting, environmentally important field of microscale testing in aquatic toxicology. Microscale Testing in Aquatic Toxicology contains over forty chapters covering relevant principles, new techniques and recent advancements, and applications in scientific research, environmental management, academia, and the private sector.

Download or read book Directory of Environmental Life Scientists South Atlantic Region Virginia Tennessee North Carolina South Carolina Mississippi Alabama Georgia Louisiana Florida written by Institute of Ecology and published by . This book was released on 1974 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fundamentals of Ecotoxicology written by Michael C. Newman and published by CRC Press. This book was released on 2019-11-27 with total page 665 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new edition is revised throughout and includes new and expanded information on natural resource damage assessment, the latest emerging contaminants and issues, and adds new international coverage, including case studies and rules and regulations. The text details key environmental contaminants, explores their fates in the biosphere, and discusses bioaccumulation and the effects of contaminants at increasing levels of ecological organization. Vignettes written by experts illustrate key themes or highlight especially pertinent examples. This edition offers an instructors' solution manual, PowerPoint slides, and supplemental images. Features: Adds all new discussions of natural resource damage assessment concepts and approaches Includes new vignettes written by leading guest authors Draws on materials from 2,500 cited sources, including 400+ new to this edition Adds numerous new entries to a useful glossary of 800+ terms Includes a new appendix discussing Brazilian environmental laws and regulations added to existing appendices outlining U.S., E.U., Chinese, Australian, and Indian environmental laws Fundamentals of Ecotoxicology: The Science of Pollution, Fifth Edition contains a broad overview of ecotoxicology and provides a basic understanding of the field. Designed as a textbook for use in introductory graduate or upper-level undergraduate courses in ecotoxicology, applied ecology, environmental pollution, and environmental science, it can also be used as a general reference for practicing environmental toxicologists.

Download or read book The Effects of Copper on Predator prey Interactions of Fathead Minnows Pimephales Promelas and Daphnia Pulex written by Christina M. Rohm and published by . This book was released on 1985 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Total copper concentrations of 10 [mu]g/l to 100 [mu]g/l appeared to alter the predator-prey interactions of fathead minnows (Pimephales promelas) and Daphnia pulex. The effect of copper concentration on the total amounts of D. pulex consumed over a 12-h period varied with the density of prey stocked hourly in the aquaria. Four prey levels of 5, 10, 20 and 30 D. pulex per 20 l aquarium were used and control consumption rates ranged from 0.9% to 4.3% of dry minnow body weight. The functional consumption response to prey density shifted from an hyperbolic-Type II toward a sigmoidal-Type III shape and the predators became more efficient at obtaining prey at lower densities as copper concentration increased. Consumption was slightly depressed at intermediate levels of copper and prey density, it was greatly enhanced at high levels of both. Mechanistic components of the functional response, total time spent searching and average time spent in pursuit of a prey item, showed an opposite pattern of response. At intermediate levels of copper concentration and prey density the total time spent searching and average time spent in pursuit increased while capture success and prey consumption fell slightly relative to controls; at high levels of copper and prey the total searching time and average time spent in pursuit decreased while capture success and prey consumption increased. Significant (P

Download or read book Aquatic Sciences and Fisheries Abstracts written by and published by . This book was released on 1994 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Handbook of Ecotoxicology written by Peter P. Calow and published by John Wiley & Sons. This book was released on 2009-06-05 with total page 901 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Handbook of Ecotoxicology provides a readily accessible, yet critical collection of information on ecotoxicological testing. Now available in a single paperback volume, this handbook represents excellent value. Part A concentrates on techniques, especially those tests used for prediction. Thorough descriptions of the main tests are provided, followed by critical analyses in terms of ease of handling, repeatability and ecological relevance, and finally, an extensive bibliography citing key documents describing test methods and key papers evaluating them. Part B focuses on the toxicants themselves: summarising their ecological effects, describing ways of predicting effects from physico-chemical properties alone, and describing and discussing fate models. Now available as a single volume in paperback An invaluable reference resource

Download or read book Applied Ecology Abstracts written by and published by . This book was released on 1979 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ecological Assessment of Environmental Degradation Pollution and Recovery written by O. Ravera and published by Elsevier. This book was released on 2012-12-02 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Ispra Course on Ecological Assessment of Environmental Degradation, Pollution and Recovery'' was structured according to the following topics: (a) terrestrial and aquatic ecosystem concept; (b) structure, functions and evolution of the ecosystem in relation to the natural and anthropogenic influences, and (c) concept of stress, assessment and restoration of terrestrial and aquatic ecosystems. These general concepts were developed in a series of lectures presented by well-known experts in their specific fields, taking into account the ecological principles and environmental management. For the various aspects of the environmental problems, the state-of-the-art, the principles of restoration techniques, the results obtained by their application and the research needs to acquire a better knowledge of the ecological processes, were discussed. The lectures were illustrated by several case studies concerning forests, lakes, reservoirs, rivers, soil and the interrelations between air and terrestrial and aquatic ecosystems.This book contains the lectures presented at the course, reviewed by the authors, and complemented throughout with numerous figures and tables.

Download or read book Trophic Consequences of Ocean Acidification written by Brittany Mary Jellison and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ocean acidification (OA) is expected to detrimentally impact marine organisms by impairing their growth, calcification, and acid-base regulation. Less is known about the capacity of OA to shift ecological interactions. In this dissertation, I examine how changes in carbonate chemistry within tidepools influence constituent members of food webs, with significance for the trophic cascades in which they are embedded. In particular, I focus on a model community within the rocky intertidal zone of the eastern Pacific Ocean that includes sea star predators, a grazing snail prey, and macroalgal basal resources. Together the findings of this dissertation suggest a potential for ocean acidification to attenuate the anti-predator behavior of intermediate consumers within food webs and influence the cascading effects imposed by predators on lower trophic levels within marine communities. Chapter one assesses the anti-predator response of a grazing snail, Tegula funebralis, to the scent of the keystone sea star predator, Pisaster ochraceus, at 16 levels of pH. In this work, I conducted laboratory experiments to quantify the full-functional flight response of Tegula under present and future tidepool conditions, assessing the propensity of this snail to enter into refuge out of the water where sea star predators tend not to follow. I found that low-pH seawater impairs the anti-predator behavior of black turban snails. I also determined that fluctuations in pH that allow snails to experience benign-pH conditions daily, typical of tidepool conditions, do not restore functional behavioral responses. The results from this chapter suggest a strong potential for low-pH seawater to alter essential behaviors that have bearing on direct and indirect components of trophic interactions. In the second chapter, I investigate how the deleterious effects of low-pH exposure on the anti-predator behavior of black turban snails, as quantified in Chapter 1, might scale up to alter ecological interactions and disrupt indirect trophic pathways. For this chapter, I conducted a mesocosm experiment using a three-level food web. By means of this model system I assessed the influence of pH on a) the foraging efficiency of a sea star predator, Leptasterias hexactis, b) the avoidance behavior of Tegula snails, and c) the accompanying consequences for the outcome of their predator-prey interaction. In addition, I determined the capacity for low pH to alter the top-down influence of predators on a lower trophic level, the macroalga, Mazzaella flaccida. Results indicate that the impaired behavior of black turban snails under low-pH conditions elevates their risk of being consumed by sea stars, and alters their foraging behavior, ultimately weakens the cascading benefits of predators on algae. In particular, while snails in ambient conditions flee predators and so spend less time grazing algae, low pH degrades the anti-predator behavior of the snails, leading them to forage on algae regardless of the presence of a sea star or not. These findings suggest that ocean acidification could weaken indirect trophic pathways and induce unexpected community-level consequences in coastal ecosystems. In the third chapter, I examine the capacity for OA to perturb relationships among species in a natural setting. I conducted a manipulative field experiment using replicate tidepools to determine how low-pH seawater modifies the direct and indirect interactions within a three-level food web that includes the keystone sea star predator, Pisaster ochraceus, the grazing snail, Tegula funebralis, and a macroalgal basal resource, Macrocystis pyrifera. I found that even under field settings, nighttime declines in tidepool pH diminished the anti-predator behavior of snails, engendering reductions in the top-down influence of predators on lower trophic levels. Snails in pools where pH was manipulated to remain at a higher level responded to predators by exiting tidepool waters and decreasing their foraging on algae. In contrast, in natural and low-pH manipulated pools, snails behaved as if sea stars were not present when they were, and consumed an equal amount of algae as in pools without a predator. These results suggest that tidepool- inhabiting snails might currently be living near their behavioral-pH thresholds and that ecological consequences of exposure to natural low-pH conditions could be exacerbated in a future ocean.

Download or read book Microbiology Abstracts written by and published by . This book was released on 1993 with total page 958 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Oceanic Abstracts with Indexes written by and published by . This book was released on 1985 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ecotoxicology written by Rachel Ann Hauser-Davis and published by CRC Press. This book was released on 2018-05-15 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents an integrated discussion on ecotoxicology, containing both general concepts and specific ecotoxicological issues of major biological groups, extending beyond conventional systems. It explores worldwide, regional, and biocompartmentalized topics, bringing forth new points of view on global issues and addressing the increasing diversity and complexity of the ecotoxicological field. It also contains novel information on emerging contaminants, presents bioaccumulation effects on different levels of ecological organization and risk analyses, and discusses novel fields of methodological applications, including key aspects in ecotoxicological and environmental monitoring studies.