Impacts of Copper Contamination and Habitat Degradation on Eelgrass (Zostera Marina) Mesograzers PDF Download
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Author: Publisher: ISBN: Category : Electronic books Languages : en Pages : 30
Book Description
Exposure of contaminants in coastal areas has been on the rise with increasing urbanization of natural environments. These contaminants are known to effect organisms in multiple ways, such as directly increasing mortality, or indirectly altering many of their behaviors, such as sensing predators and foraging. Since seagrass habitats are heavily influenced by anthropogenic factors, organisms found in these ecosystems often experience constant exposure to non-degradable contaminants such as heavy metals. Eelgrass (Zostera marina) persistence is promoted by mesograzers (small crustaceans and gastropods) that control competing epiphytic algae growing on seagrass blades. Along with nutrient levels, this top-down control of a dominant competitor (algae) plays a substantial role in dictating eelgrass health, particularly at high levels of eelgrass structural complexity. However, mesograzers can be negatively affected by contaminants at high levels. I conducted a manipulative field experiment on epifaunal colonization of eelgrass in San Diego Bay, and a companion lab experiment on epifaunal grazing, to determine how epiphytic algae, the mesograzer community, and rates of herbivory are interactively affected by dissolved copper and habitat structural complexity. In the field, copper spiked plaster blocks and artificial seagrass units were used to create realistic pulse events of contamination for two levels of habitat structural complexity. I found that the abundance of epiphytic algae decreased with increasing copper, but that copper had no effect on epifaunal abundance or diversity, which responded strongly only to habitat structural complexity. In the lab experiment, I found complex interactive effects of copper concentration and habitat complexity on grass shrimp grazing rates. Low elevated levels of copper resulted in higher grazing in low complexity vs. high complexity eelgrass, in contrast to trends in ambient and high levels of copper as well as in previous experiments. In both low and high structural complexity eelgrass, grass shrimp grazing impact was highest when copper was elevated compared to ambient levels. In order to set effective regulations, understanding both the direct and indirect interactions between organisms and their environment is key in conserving and managing eelgrass habitat.
Author: Publisher: ISBN: Category : Electronic books Languages : en Pages : 30
Book Description
Exposure of contaminants in coastal areas has been on the rise with increasing urbanization of natural environments. These contaminants are known to effect organisms in multiple ways, such as directly increasing mortality, or indirectly altering many of their behaviors, such as sensing predators and foraging. Since seagrass habitats are heavily influenced by anthropogenic factors, organisms found in these ecosystems often experience constant exposure to non-degradable contaminants such as heavy metals. Eelgrass (Zostera marina) persistence is promoted by mesograzers (small crustaceans and gastropods) that control competing epiphytic algae growing on seagrass blades. Along with nutrient levels, this top-down control of a dominant competitor (algae) plays a substantial role in dictating eelgrass health, particularly at high levels of eelgrass structural complexity. However, mesograzers can be negatively affected by contaminants at high levels. I conducted a manipulative field experiment on epifaunal colonization of eelgrass in San Diego Bay, and a companion lab experiment on epifaunal grazing, to determine how epiphytic algae, the mesograzer community, and rates of herbivory are interactively affected by dissolved copper and habitat structural complexity. In the field, copper spiked plaster blocks and artificial seagrass units were used to create realistic pulse events of contamination for two levels of habitat structural complexity. I found that the abundance of epiphytic algae decreased with increasing copper, but that copper had no effect on epifaunal abundance or diversity, which responded strongly only to habitat structural complexity. In the lab experiment, I found complex interactive effects of copper concentration and habitat complexity on grass shrimp grazing rates. Low elevated levels of copper resulted in higher grazing in low complexity vs. high complexity eelgrass, in contrast to trends in ambient and high levels of copper as well as in previous experiments. In both low and high structural complexity eelgrass, grass shrimp grazing impact was highest when copper was elevated compared to ambient levels. In order to set effective regulations, understanding both the direct and indirect interactions between organisms and their environment is key in conserving and managing eelgrass habitat.
Author: Publisher: ISBN: Category : Electronic books Languages : en Pages : 39
Book Description
A central theory of community ecology is that increased biodiversity results in greater ecosystem function and stability. Many experiments have examined biodiversity-ecosystem function (BEF) relationships at the primary producer level, yet BEF relationships are equally pertinent at higher trophic levels. In seagrass ecosystems, mesograzers (small invertebrate herbivores) promote seagrass persistence by consuming competitively superior epiphytic algae that foul seagrass blades. Experiments in seagrass habitat suggest that mesograzer diversity is a primary driver of top-down control of epiphytic algae, but also that the relationship is temporally and spatially variable. The primary hypothesis of my study is that much of this variability may be due to differences in seagrass habitat structure through time and space. I worked in eelgrass (Zostera marina) habitat in San Diego Bay, California, USA, to test whether variability in eelgrass structural complexity (shoot density) affects relationships between mesograzer biodiversity and ecosystem function (grazing impact and secondary production). I also examined the functional roles of numerically dominant eelgrass epifauna, using a laboratory experiment and stable isotope analysis. Contrary to BEF theory, increased grazer diversity in laboratory mesocosms resulted in decreased grazing impact and facilitation of algal growth. Though some species combinations resulted in increased algal grazing, antagonistic relationships among the most influential grazing taxa resulted in reduced ecosystem function. Structural complexity promoted mesograzer top-down control of epiphytes, increased mesograzer secondary production, and altered epifaunal community composition. Effects of biodiversity and structural complexity on grazing corresponded to variability in diet and feeding behavior among dominant epifaunal taxa. My results demonstrate the importance of examining species-specific interactions when considering links between community structure and ecosystem function, and that environmental context, such as habitat structure, may have large effects on BEF relationships.
Author: Zi-Min Hu Publisher: Springer ISBN: 9401775346 Category : Science Languages : en Pages : 398
Book Description
The book provides an overview of research on the remarkable diversity, adaptive genetic differentiation, and evolutionary complexity of intertidal macroalgae species. Through incorporating molecular data, ecological niche and model-based phylogeographic inference, this book presents the latest findings and hypotheses on the spatial distribution and evolution of seaweeds in the context of historical climate change (e.g. the Quaternary ice ages), contemporary global warming, and increased anthropogenic influences. The chapters in this book highlight past and current research on seaweed phylogeography and predict the future trends and directions. This book frames a number of research cases to review how biogeographic processes and interactive eco-genetic dynamics shaped the demographic histories of seaweeds, which furthermore enhances our understanding of speciation and diversification in the sea. Dr. Zi-Min Hu is an associate professor at Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China. Dr. Ceridwen Fraser is a senior lecturer at Fenner School of Environment and Society, Australian National University, Canberra, Australia.
Author: D. M. John Publisher: Clarendon Press ISBN: Category : Nature Languages : en Pages : 600
Book Description
Traditional compartmentalization of biological sciences is increasingly breaking down or being considered irrelevant by new generations of biological scientists. Marine biologists have generally been ahead of such trends, as is evident from much recent research on plant-animal interactions in the marine benthos.
Author: Emil Olafsson Publisher: CRC Press ISBN: 1498723268 Category : Nature Languages : en Pages : 286
Book Description
Marine macrophytes (macroalgae, seagrasses, and mangroves) comprise thousands of species distributed in shallow water areas along the world’s coastlines. They play a key role in marine ecosystems regarding biodiversity and energy flow. A large proportion of macrophyte species can be characterised as ecosystem engineers—organisms that directly or indirectly affect the availability of resources to other species by modifying, maintaining, and creating habitats. This book is divided into three main themes: • Marine macroalgae and seagrasses as sources of biodiversity gives an overview of the diversity of the main organisms associated with macrophytes, and their functional role and interactions within their hosts. • Primary and secondary production of Macrophytes synthesizes research on food web structures derived from/or associated with, macrophytes and the transfer of macrophytic primary and secondary production from one ecosystem to another. • Threats to macrophytic ecosystem engineers addresses human-induced effects including eutrophication, physical destruction, invasive species, and global warming. The book is among the first one to concentrate on the value of macrophytes for the well-being of marine habitats. The book is aimed at academics but may be useful for students, policy makers, and laymen alike.
Author: Dennis A. Hansell Publisher: Academic Press ISBN: 0124071538 Category : Science Languages : en Pages : 712
Book Description
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
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Author: Danielle Healey
Author: Zi-Min Hu
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Author: D. M. John
Author: Johanna E. Johnson
Author: Emil Olafsson
Author: Dennis A. Hansell