Download or read book Factors Affecting Stable Carbon and Nitrogen Isotopic Signatures in Food Webs of the Ste Marguerite River System Quebec Canada written by Véronique Trudeau and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Deeper understanding of the factors controlling stable isotopic signatures of aquatic organisms of all trophic levels is required if we are to properly use them in food web studies and as environmental indicators. The present field study conducted in the Ste. Marguerite River system, Quebec, compared periphyton signatures found in eight reaches (sections of a river/tributary) each composed of a series of sites with different flow regimes. Similar to patterns found in the laboratory, periphyton delta13C significantly decreased with increasing water velocity. In addition, periphyton biomass positively affected periphyton delta13C. Isotopic fractionation in favour of 12C by the periphyton communities likely leads to build-up of the heavier isotope in the boundary layer of algae. This study allows a better understanding of aquatic plant delta13C fluctuations. It also suggests how much variability in aquatic consumer delta13 C can be explained by water velocity in lotic systems." --

Download or read book Factor Affecting Stable Carbon and Nitrogen Isotopic Signatures in Food Webs of the Ste Marguerite River System Quebec Canada written by Véronique Trudeau and published by . This book was released on 2005 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Stable Carbon and Nitrogen Isotope Study of Lake Food Webs in Canada s Boreal Plain written by Ellie E. Prepas and published by . This book was released on 2001 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Large River Food Webs written by Katherine Roach and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Humans impact rivers in many ways that modify ecological processes yielding ecosystem services. In order to mitigate anthropogenic impacts, scientists are challenged to understand interactions among physicochemical factors affecting large river food webs. An understanding of socioeconomic factors also is critical for ecosystem management. In this dissertation, I explore spatiotemporal patterns in floodplain river food webs and political barriers to management of environmental flows, an important factor influencing river ecology. In Chapter II, I reviewed the scientific literature to test conceptual models of river food webs and predictions of environmental factors that might produce variation in basal production sources supporting consumer biomass. My review indicates that algae are the predominant production source for large rivers worldwide, but consumers assimilate C3 plants in rivers 1) with high sediment loads and low transparency during high flow pulses, 2) with high dissolved organic matter concentrations, and 3) following periods of high discharge or leaf litter fall that increase the amount of terrestrial material in the particulate organic matter pool. In Chapter III, I descrobe field research conducted to examine relationships among hydrology, nutrient concentrations, turbidity, and algal primary production and biomass in the littoral zone of five rivers in Texas, Peru, and Venezuela differing in physicochemical conditions. I used stable isotope signatures to estimate contributions of algal-versus terrestrial-based production sources to consumers during different hydrologic periods. My research indicates that during flow pulses in floodplain rivers, a decrease in algal biomass and productivity, combined with increased inputs of terrestrial organic matter, can result in increased terrestrial support of metazoan consumers in the aquatic food web. In 2007, Texas Senate Bill 3 directed that environmental flow recommendations be developed for river basins. Despite emphasis on use of the "best available science" to develop environmental flow regimes and "stakeholder involvement" to address needs of all water users, for the first two basins to complete the SB3 process, final environmental flow rules did not mimic a natural flow regime. In Chapter IV, I reviewed this process, concluding that incentives for river authorities to increase compromise with diverse stakeholders should result in more sustainable management of freshwater.

Download or read book Understanding the Effects of Consumers and Light on Stream Food Webs Using Stable Isotope Techniques written by Sarah Michelle Collins and published by . This book was released on 2015 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: In headwater streams that are heavily shaded by surrounding forests, primary production is often low and inputs of particulate and dissolved organic carbon from terrestrial environments are important resources in food webs. Stable isotope methods are useful for quantifying food web fluxes of different carbon sources but data are frequently difficult to interpret. Here, I developed novel stable isotope techniques to study the role of terrestrial energy subsidies in stream food webs in Trinidad and Tobago and the Adirondack region of New York. Specifically, I sought to determine the importance of carbon sources from terrestrial environments versus in-stream primary production in streams with varying light availability and fish communities. I compared natural canopy streams to streams with experimentally thinned canopies using a novel carbon and nitrogen dual isotope tracer technique. Comparing data from 13 C-acetate tracers, which are assimilated only by heterotrophic bacteria, and 15N- ammonium tracers, which are assimilated by both heterotrophs and autotrophs, allowed me to evaluate the relative importance of terrestrial carbon inputs and heterotrophic pathways. I also compared food webs in Trinidad and Adirondack streams along a natural gradient of canopy cover using stable isotopes of hydrogen, which indicated how much terrestrial organic matter was assimilated by consumers. In the Adirondacks, terrestrial carbon subsidies and heterotrophic bacteria were important resources for consumers, but the amount of bacterial carbon assimilated by invertebrates declined when light availability and primary production were experimentally increased. Fish introductions and light availability both influenced food webs in Trinidad streams. There were increased fluxes of carbon and nitrogen to consumers in streams with high light. Effects of fish introduction varied by consumer taxon, with strong positive effects of fish on filter-feeding invertebrates, and weaker positive effects of fish on grazer invertebrates. In comparative studies across light gradients, most consumer taxa were flexible in the amount of terrestrial carbon they assimilated, with higher reliance on terrestrial subsidies in streams with high canopy cover than in larger streams with less canopy cover. Overall, these results suggest that the light environment can have a strong influence on the role of terrestrial subsidies in streams.

Download or read book A Stable Carbon Isotope Study of the Food Web in Bayboro Harbor St Petersburg Florida written by Margarita E. Mangini and published by . This book was released on 1983 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Food Web Analysis of a Mojave Desert Geothermal Spring System and Feeding Ecology of Moapa Dace Moapa Coriacea written by Adam St Saviour and published by . This book was released on 2011 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding food webs is fundamental in conserving endangered species and maintaining healthy ecosystem function, particularly in desert spring systems. We identified dominant energy sources in the Muddy River Warm Springs area, Clark County, NV using carbon and nitrogen natural abundance stable isotope analyses. We examined isotopic signatures of specific macroinvertebrate food resources for the endangered, drift-feeding Moapa dace (Moapa coriacea) and looked for changes in isotopic ratios over the stream gradient. Our results indicate the Muddy River Warm Springs area is supported primarily by allochthonous energy sources, and Moapa dace did not focus on specific macroinvertebrate taxa. We characterized a pattern of downstream [delta]13C enrichment, which is seemingly common in groundwater-fed systems but discussed very little in the literature. We conclude that ground water carbon of marine origin, heterotrophic respiration, and fractionation and depletion of the [delta]13C pool by autotrophs contribute to a wide range [delta]13C values in primary producers and to the downstream enrichment pattern in the Muddy River Warm Springs. We then quantified macroinvertebrate drift throughout the Moapa dace's current and historic range within the Muddy River Warm Springs. We examined the relationship of total drift biomass and temperature and associations between specific macroinvertebrate orders and Moapa dace abundance. We also explored habitat characteristics associated with Moapa dace and their prey. In 2008 and 2009, total drift biomass/time and the biomass of most orders was negatively correlated with temperature and positively correlated with discharge. Only Lepidoptera and Neotaenioglossa had positive associations with temperature in 2008. In 2009, total biomass/volume had a negative linear relationship with temperature and a positive linear relationship with discharge, though these relationships were absent in 2008. Moapa dace were associated with high temperatures, low stream discharge, shallow depth, and low drift biomass both years. They were positively associated with thermally tolerant Lepidoptera and Neotaenioglossa in 2008 and no orders in 2009. Macroinvertebrate drift may be greater in cooler, downstream reaches because temperatures in those reaches are favorable to more taxa, there is more cumulative benthic area contributing to production, and there are fewer drift feeding insectivores. Lastly, we examined Moapa dace feeding flexibility by experimentally manipulating drift (0, 34, 64, 100, and 200% of the natural drift level) and quantified their feeding attempts and success. We found that Moapa dace are obligate drift feeders, selecting drift 40 times more frequently than benthos. They did not adaptively shift foraging modes from drift to benthic when drift was experimentally reduced. Drift feeding rate increased in response to increasing drift, but drift feeding success only increased from the 0% to the 64% drift level and did not change in the 100% and 200% levels. No relationship between fish size or food availability and aggression was detected. Moapa dace may share an interspecific foraging association with sympatric White River springfish (Crenichthys baileyi). Moapa dace are currently excluded from lower, more productive reaches by invasive species and fish barriers. Maintaining spring flows, eradicating non-natives, and restoring system connectivity will likely benefit Moapa dace and other Muddy River Warm Springs endemics.

Download or read book Conserving the Oceans written by Justin Alger and published by Oxford University Press. This book was released on 2021 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Conserving the Oceans: The Politics of Large Marine Protected Areas documents the efforts of activists and states to increase the pace and scale of global ocean protections, leading to a new global norm in ocean conservation of large marine protected areas exceeding 200,000 km2. Through an analysis of domestic political economies, the book explains how states have protected millions of square kilometers of ocean space while remaining highly responsive to the interests of businesses. It argues that states design environmental policies above all around two key features of a given space: (1) the composition of extractive versus non-extractive industry interests; and (2) the salience of various industry interests, defined as the degree to which businesses would suffer tangible and significant costs in response to new environmental regulations. Through an analysis of large marine protected area advocacy campaigns in Australia, Palau, and the United States, this book demonstrates how the political economy of a given marine space shapes how governments align their environmental and economic goals, sometimes strengthening conservation but more often than not undermining it. While recognizing important global progress and growing ambition to conserve ocean ecosystems, Conserving the Oceans demonstrates that even ambitious large marine protected areas have so far not fundamentally challenged a neoliberal paradigm of environmentalism that has caused considerable ecological harm"--

Download or read book The Ecosystem Approach written by Gene E. Likens and published by . This book was released on 1992 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Concepts and Controversies in Tidal Marsh Ecology written by M.P. Weinstein and published by Springer Science & Business Media. This book was released on 2000-10-31 with total page 862 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tidal salt marshes are viewed as critical habitats for the production of fish and shellfish. As a result, considerable legislation has been promulgated to conserve and protect these habitats, and much of it is in effect today. The relatively young science of ecological engineering has also emerged, and there are now attempts to reverse centuries-old losses by encouraging sound wetland restoration practices. Today, tens of thousands of hectares of degraded or isolated coastal wetlands are being restored worldwide. Whether restored wetlands reach functional equivalency to `natural' systems is a subject of heated debate. Equally debatable is the paradigm that depicts tidal salt marshes as the `great engine' that drives much of the secondary production in coastal waters. This view was questioned in the early 1980s by investigators who noted that total carbon export, on the order of 100 to 200 g m-2 y-1 was of much lower magnitude than originally thought. These authors also recognized that some marshes were either net importers of carbon, or showed no net exchange. Thus, the notion of `outwelling' has become but a single element in an evolving view of marsh function and the link between primary and secondary production. The `revisionist' movement was launched in 1979 when stable isotopic ratios of macrophytes and animal tissues were found to be `mismatched'. Some eighteen years later, the view of marsh function is still undergoing additional modification, and we are slowly unraveling the complexities of biogeochemical cycles, nutrient exchange, and the links between primary producers and the marsh/estuary fauna. Yet, since Teal's seminal paper nearly forty years ago, we are not much closer to understanding how marshes work. If anything, we have learned that the story is far more complicated than originally thought. Despite more than four decades of intense research, we do not yet know how salt marshes function as essential habitat, nor do we know the relative contributions to secondary production, both in situ or in the open waters of the estuary. The theme of this Symposium was to review the status of salt marsh research and revisit the existing paradigm(s) for salt marsh function. Challenge questions were designed to meet the controversy head on: Do marshes support the production of marine transient species? If so, how? Are any of these species marsh obligates? How much of the production takes place in situ versus in open waters of the estuary/coastal zone? Sessions were devoted to reviews of landmark studies, or current findings that advance our knowledge of salt marsh function. A day was also devoted to ecological engineering and wetland restoration papers addressing state-of-the-art methodology and specific case histories. Several challenge papers arguing for and against our ability to restore functional salt marshes led off each session. This volume is intended to serve as a synthesis of our current understanding of the ecological role of salt marshes, and will, it is hoped, pave the way for a new generation of research.

Download or read book Hydroecology and Ecohydrology written by Paul J. Wood and published by John Wiley & Sons. This book was released on 2008-02-28 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: This state-of-the-art, research level text considers the growing volume of research at the interface of hydrology and ecology and focuses on: the evolution of hydroecology / ecohydrology process understanding hydroecological interactions, dynamics and linkages methodological approaches detailed case studies future research needs The editors and contributors are internationally recognised experts in hydrology and ecology from institutions across North America, South America, Australia, and Europe. Chapters provide a broad geographical coverage and bridge the traditional subject divide between hydrology and ecology. The book considers a range of organisms (plants, invertebrates and fish), provides a long-term perspective on contemporary and palaeo-systems, and emphasises wider research implications with respect to environmental and water resource management. Hydroecology and Ecohydrology is an indispensable resource for academics and postgraduate researchers in departments of physical geography, earth sciences, environmental science, environmental management, civil engineering, water resource management, biology, zoology, botany and ecology. It is also of interest to professionals working within environmental consultancies, organizations and national agencies.

Download or read book Isotope Geology written by Claude J. Allègre and published by . This book was released on 2008-12-04 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive introductory textbook to isotope techniques for undergraduate and graduate courses.

Download or read book Ecosystem Experiments written by Harold A. Mooney and published by . This book was released on 1991-10-24 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Incorporates the results of the program on ecosystem experiments conducted by the Scientific Committee of Problems of the Environment. Features research papers submitted at Mitwitz, Germany and Washington, D.C. The objective of this compilation of papers is to explore the potential of ecosystem experimentation as a tool for understanding and predicting changes in the biosphere. Areas investigated include deforestation, desertification, El Nino phenomenon, acid rain, watersheds, wetlands, aquatic and climatic changes.

Download or read book Hydrology for Urban Land Planning written by Luna Bergere Leopold and published by . This book was released on 1968 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Surviving Sudden Environmental Change written by Jago Cooper and published by University Press of Colorado. This book was released on 2012-02-01 with total page 355 pages. Available in PDF, EPUB and Kindle. Book excerpt: Archaeologists have long encountered evidence of natural disasters through excavation and stratigraphy. In Surviving Sudden Environmental Change, case studies examine how eight different past human communities—ranging from Arctic to equatorial regions, from tropical rainforests to desert interiors, and from deep prehistory to living memory—faced, and coped with, such dangers. Many disasters originate from a force of nature, such as an earthquake, cyclone, tsunami, volcanic eruption, drought, or flood. But that is only half of the story; decisions of people and their particular cultural lifeways are the rest. Sociocultural factors are essential in understanding risk, impact, resilience, reactions, and recoveries from massive sudden environmental changes. By using deep-time perspectives provided by interdisciplinary approaches, this book provides a rich temporal background to the human experience of environmental hazards and disasters. In addition, each chapter is followed by an abstract summarizing the important implications for today’s management practices and providing recommendations for policy makers. Publication supported in part by the National Science Foundation.

Download or read book Zooplankton and Nekton Gatekeepers of the Biological Pump written by Rainer Kiko and published by Frontiers Media SA. This book was released on 2020-09-14 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.

Download or read book Biogeochemistry of Marine Dissolved Organic Matter written by Dennis A. Hansell and published by Academic Press. This book was released on 2014-10-02 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine dissolved organic matter (DOM) is a complex mixture of molecules found throughout the world's oceans. It plays a key role in the export, distribution, and sequestration of carbon in the oceanic water column, posited to be a source of atmospheric climate regulation. Biogeochemistry of Marine Dissolved Organic Matter, Second Edition, focuses on the chemical constituents of DOM and its biogeochemical, biological, and ecological significance in the global ocean, and provides a single, unique source for the references, information, and informed judgments of the community of marine biogeochemists. Presented by some of the world's leading scientists, this revised edition reports on the major advances in this area and includes new chapters covering the role of DOM in ancient ocean carbon cycles, the long term stability of marine DOM, the biophysical dynamics of DOM, fluvial DOM qualities and fate, and the Mediterranean Sea. Biogeochemistry of Marine Dissolved Organic Matter, Second Edition, is an extremely useful resource that helps people interested in the largest pool of active carbon on the planet (DOC) get a firm grounding on the general paradigms and many of the relevant references on this topic. Features up-to-date knowledge of DOM, including five new chapters The only published work to synthesize recent research on dissolved organic carbon in the Mediterranean Sea Includes chapters that address inputs from freshwater terrestrial DOM