Lake Food Web Responses Across Environmental Gradients
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Lake Food Web Responses Across Environmental Gradients
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Author : Tyler Tunney
language : en
Publisher:
Release Date : 2014
Lake Food Web Responses Across Environmental Gradients written by Tyler Tunney and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with categories.
Combined Effects Of Resources And Warming On Lake Microbial Communities Across Environmental Gradients
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Author : Marika A. Schulhof
language : en
Publisher:
Release Date : 2018
Combined Effects Of Resources And Warming On Lake Microbial Communities Across Environmental Gradients written by Marika A. Schulhof and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.
Multiple aspects of the global environment are changing rapidly, including rising temperatures, altered biogeochemical cycles and a redistribution of biodiversity. Different aspects of environmental change may interact through synergistic processes or interference; however, how these processes magnify or dampen one another's effects on lakes is largely unknown. My dissertation research explores the independent and interactive effects of warming and resource supply on lake food webs from multiple perspectives. Chapter 1 investigates the independent and interactive effects of temperature, supply and origin of dissolved organic material, and atmospheric nitrogen deposition on prokaryotic and eukaryotic microbial community composition and diversity in Sierra Nevada lakes. Chapter 2 focuses on stoichiometry and growth of phytoplankton communities in response to warming, nutrient addition and grazing in three Dutch lakes across a productivity gradient. Chapter 3 explores whether the competition-defense tradeoff regulates coexistence within or among members of phytoplankton communities across a productivity gradient, and how warming may alter this tradeoff. These studies collectively show that resource supply is more important than temperature in regulating microbial community composition and stoichiometry across a variety of lake ecosystems. Additionally, interactive effects of temperature, nutrient supply, and grazing on phytoplankton community stoichiometry, growth rates, biomass buildup and functional group composition depend on the trophic state and size structure of communities. Finally, turnover in communities along productivity gradients resulted in a positive correlation between nutrient and grazer limitation across taxa among lakes, but no relationship between top-down and bottom-up limitation within lakes. This result suggests that traits like small cell size that make phytoplankton more susceptible to grazing also confer strong responses to nutrient pulses in low-nutrient environments. Thus, my results provide no support for the hypothesis that costly defenses against grazing increase nutrient limitation, resulting in a tradeoff between nutrient and consumer limitation. In fact, the opposite pattern was found whereby the taxa that are most sensitive to grazing and nutrients are segregated in the least productive system, and the responses to both factors decline in more productive lakes due to increasing dominance by inedible forms. My thesis demonstrates functional associations among the traits of microbes that shape their responses to climate, resources and consumers, promote diversity at the local and regional scales, and determine how aquatic ecosystem productivity is controlled by multiple limiting factors.
Aquatic Food Webs
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Author : Andrea Belgrano
language : en
Publisher: Oxford University Press, USA
Release Date : 2005
Aquatic Food Webs written by Andrea Belgrano and has been published by Oxford University Press, USA this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with Science categories.
'Aquatic Food Webs' provides a current synthesis of theoretical and empirical food web research. The textbook is suitable for graduate level students as well as professional researchers in community, ecosystem, and theoretical ecology, in aquatic ecology, and in conservation biology.
Investigating Ecosystem Scale Responses To Changes In Lake Food Webs
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Author : Tyler James Butts
language : en
Publisher:
Release Date : 2023
Investigating Ecosystem Scale Responses To Changes In Lake Food Webs written by Tyler James Butts and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023 with categories.
Aquatic ecosystems are increasingly facing ecosystem-scale disturbances that affect water quality and ecosystem services. Food webs have substantial influences on how disturbances are propagated through ecosystems and the structure of trophic interactions shapes nutrient cycling and energy flow. In my dissertation, I used food webs to improve the understanding of dynamics in disturbed ecosystems, and develop our understanding of how food webs mediate, and respond to, increasingly frequent and intense disturbances. Chapter 1 used lower food web dynamics to assess consumer nutrient cycling within a hypereutrophic reservoir, demonstrating that the lower food web has a substantial influence on early summer phosphorus availability and phytoplankton size structure. Chapter 2 quantified zooplankton and macroinvertebrate size structure as a tool to assess food web response to an incentivized harvest of common carp (Cyprinus carpio) and bigmouth buffalo (Ictiobus cyprinellus). This analysis showed that the biomanipulation did not significantly affect food web structure potentially explaining the lack of water quality response. Expanding to the whole food web, chapter 3 tested whether food web structure mediates ecosystem responses to discrete disturbance-storm-driven nutrient loading-finding greater benthic-pelagic coupling increased the resistance and resilience of algal biomass response to pulsed nutrient loading events. Chapter 4 used a bioenergetics approach to explore changes in energy flux and food web stability over 19 years in the Trout Lake pelagic food web, including an invasion by a mid-trophic level invader, Bythotrephes longimanus. This analysis highlighted how a mid-trophic level invader alters the trajectory of an ecosystem by decreasing energy flux and temporarily altering food web stability. In summary, this research has advanced our understanding of how food webs drive ecosystem function and mediate ecosystem-scale responses within aquatic ecosystems.
Responses Of Freshwater Food Webs To Spatial Temporal Ph Gradients
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Author : Katrin Layer
language : en
Publisher:
Release Date : 2009
Responses Of Freshwater Food Webs To Spatial Temporal Ph Gradients written by Katrin Layer and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with categories.
Responses Of Freshwater Food Webs To Spatial And Temporal Ph Gradients
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Author : Katrin Layer
language : en
Publisher:
Release Date : 2009
Responses Of Freshwater Food Webs To Spatial And Temporal Ph Gradients written by Katrin Layer and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with categories.
The Ecology And Evolution Of Top Down And Bottom Up Control In Mountain Lakes
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Author : Celia C. Symons
language : en
Publisher:
Release Date : 2017
The Ecology And Evolution Of Top Down And Bottom Up Control In Mountain Lakes written by Celia C. Symons and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
Determining factors that control how biomass is distributed among plants, animals, microbes and non-living components of ecosystems is a major goal of ecology. Theoretical and empirical work have demonstrated that ecosystem structure and function may vary with the environment, but studies often overlook the role of adaptation and shifts in species composition that will occur over longer timescales relevant to climate change. For my doctoral research I used a 'natural experiment' in Sierra Nevada mountain lakes to ask questions about the strength of top-down and bottom-up forcing in a natural system where communities have assembled and adapted to differences in the environment over periods from years to millennia. In Chapter 1 I compare fish and fishless lakes along an elevational gradient, and show that an interaction between fish presence and temperature alters food web structure, ecosystem function, species and trait composition. Top-down forcing from fish on plankton biomass was stronger in warm lakes, suggesting that a warmer climate will magnify the effect of introduced predators on biomass distribution. Fish and warmer temperatures select for the same species and traits of zooplankton in lakes, suggesting that lakes containing invasive predators may be less sensitive to warming. In Chapter 2 I test this hypothesis using a large-scale community transplant experiment, where I transplanted plankton communities that assembled and evolved at different elevations and predator regimes to new elevations and the addition or removal of fish. I found that past exposure to fish caused an evolutionary response in keystone members of the zooplankton community that increased their fitness in environments without fish. This suggests that past selection can change how communities will respond to further environmental change. In Chapter 3, I show that bottom-up processes influence fish growth, with higher growth rates occurring in warmer, clearer lakes. My thesis helps to elucidate the effects of temperature and predators on physiology, evolution, species ranges and community interactions, which is necessary to forecast the response of ecosystems to climate change. My thesis integrates across these levels of organization to understand the origin of ecosystem resilience in a changing climate.
Species Responses To Environmental Fluctuations
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Author : Sara Gudmundson
language : en
Publisher:
Release Date : 2017
Species Responses To Environmental Fluctuations written by Sara Gudmundson and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
Food Webs At The Landscape Level
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Author : Gary A. Polis
language : en
Publisher: University of Chicago Press
Release Date : 2004-02-22
Food Webs At The Landscape Level written by Gary A. Polis and has been published by University of Chicago Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004-02-22 with Science categories.
Paying special attention to the fertile boundaries between terrestrial, freshwater, and marine ecosystems, this work shows not only what this new methodology means for ecology, conservation, and agriculture but also serves as a fitting tribute to Gary Polis and his major contributions to the field
Littoral Structure As A Driver Of Food Chain Length In Lakes
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Author : Jacob Ziegler
language : en
Publisher:
Release Date : 2014
Littoral Structure As A Driver Of Food Chain Length In Lakes written by Jacob Ziegler and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with categories.
"Lakes are among the most susceptible ecosystems to anthropogenic modification as humans are drawn to freshwaters for the multitude of ecosystems services they provide. The littoral habitat structure of lakes, both in the form of aquatic vegetation (macrophytes) and coarse woody debris (CWD), is often negatively altered by direct and indirect human activities. Little is known about the effect that loss of littoral structure might have on whole lake food webs with respect to energy flow and trophic transfers. The maximum number of trophic transfers within a food web is referred to as food chain length and can control community composition through trophic cascades. Therefore, detectable changes in food chain length likely have impacts on the lake food web. I predicted that loss of littoral structure would result in reduced food chain length due to loss of refuge for intermediate consumers. I used a field study and a simulation model to (1) determine if there was a significant relationship between food chain length and littoral structure in the form of macrophytes and (2) assess the support for two different potential mechanisms (i.e. for changes in refuge or productivity) through which macrophytes and coarse woody debris could alter food chain length. The field study showed that food chain length was positively related to macrophyte abundance. The simulation model shed further insight and showed that refuge provided by macrophytes and CWD may account for observed food chain length increases due to preservation of predatory invertebrates. From these results, we can infer that the loss of littoral habitat structure likely results in a shortening of the lake food chain, which can have implications for community composition, energy flow and whole ecosystem responses to change." --