Physical Sciences and Mathematics Commons^™

Assessing Chemical And Biological Recovery From Acid Rain Deposition In Montane Vermont Lakes, Sydney Diamond

Graduate College Dissertations and Theses

Vermont’s inland lakes are changing rapidly in response to anthropogenic disturbance pressures. While changes in water chemistry are well documented across the state, the biological response of primary producer communities to these shifts remains poorly understood. This project investigated the response of phytoplankton communities to the interacting effects of recovery from acidification and climate change in high-altitude lakes. We analyzed long-term monitoring and meteorological data in four of Vermont’s acid-impaired lakes and found that as pH and acid-neutralizing capacity has increased, so have concentrations of dissolved organic carbon (DOC) in most lakes. To assess the biological response to these processes, …

Spatial And Temporal Variation Of Phytoplankton Production In Lake Michigan, Katelyn Alexis Bockwoldt

Theses and Dissertations

Although many studies have documented decreases in phytoplankton production since the quagga mussel invasion, we currently have a limited understanding of the spatial variation and temporal dynamics of phytoplankton production in Lake Michigan. In this study, phytoplankton production and seston stoichiometry were measured bi-weekly near Milwaukee, three times at two northern basin sites, and along three nearshore-offshore transects from May to November 2017, as well as at 5-6 sites on three whole-lake surveys in 2016 and 2017. Estimates of growth rates were calculated from phytoplankton production and carbon measurements. In spring 2016 and 2017, growth estimates were similar across the …

Antibiotics And Antibiotic-Resistant Bacteria In Coastal Plain Streams, Jason Duff

Electronic Theses and Dissertations

Streams across the United States and globally are influenced by environmental contamination, including antibiotics, which enter streams due to widespread use and multiple pathways into the environment. Antibiotics are also likely to enter streams in mixture with other contaminants that alter the effects on aquatic organisms. Furthermore, antibiotic-resistant bacteria enter streams through similar pathways as antibiotics with implications for natural microbial communities. Therefore, understanding the presence and effects of antibiotic-contaminant mixtures and antibiotic-resistant bacteria in streams is important for resource management.

Chapter one describes an experiment that tested the hypothesis that the antibiotic tetracycline (TC) alone influences phytoplankton communities differently …

Modelling Of Dreissenid Mussel Impacts On Lake Michigan, Chunqi Shen

Theses and Dissertations

Invasive dreissenid mussel appear to have profoundly altered Great Lakes food webs and nutrient cycles during the past several decades. Recent declines of phytoplankton were supposed to be highly related with the increase of mussel population. These phytoplankton declines were further found to be coincident with declines in the abundance of planktivorous fish. In addition, the resurgence of Cladophora in Great lakes was estimated to be associated with the high density colonization of mussels. More light is available at lake bottom due to the mussels’ graze effect. The mussels further promote Cladophora growth by fertilizing it with nutrient-rich excrement. And …

Exploration Of Spatial And Temporal Changes In Trophic Status Of Lakes In The Northern Temporal Forest Biome Using Remote Sensing, Aleksey Paltsev

Electronic Thesis and Dissertation Repository

There is a critical need for detailed surveys of lakes covering large spatial (>100 km²) and temporal scales (decades) to determine if there is an increase in the magnitude and frequency of phytoplankton blooms. Remote sensing was used to: (1) develop a regression model that relates chlorophyll a (chl-a) as a proxy of lake phytoplankton biomass to Landsat TM and ETM+ optical reflectance (r²=0.85, p

Reservoir Management Techniques To Enhance Biological Productivity And Protect Water Quality, Ben Alan Thompson

Graduate Theses and Dissertations

Three reservoirs of similar size, watershed land use, and qualitative characteristics in northwest Arkansas, USA were selected to compare the effects of chemical fertilization and pulsed artificial-upwelling on whole-lake productivity, specifically primary production and phytoplankton biomass. Numerous water quality parameters were quantified over a two year period (2011-13) with the goal of understanding how each management technique would stimulate productivity. This experiment was the first step towards a larger goal to ultimately enhance sport fish production. The first year of monitoring occurred in 2011 and served as a control year for the three lakes. Treatments were initiated in two of …

Phytoplankton Life History Events: Resting Stages And Physiological Cell Death, Christine R. Kozik

Theses and Dissertations

Understanding and predicting changes in phytoplankton populations requires knowledge of key life history processes such as recruitment from benthic resting stages and losses due to sedimentation and cell death. Currently, these processes are poorly understood in freshwater systems. Phytoplankton resting stage and cell death life history events were separately examined in two freshwater systems in Wisconsin, four northern lakes and an urban pond. In the norther lakes, sedimentation and benthic recruitment were examined using sediment and recruitment traps that were sampled weekly over two summers. Sedimentation and benthic recruitment contributed little to changes in standing crop chl a, but rather …

A Comparison Of Phytoplankton Communities In Lake Prince And The Western Branch Reservoir, Suffolk, Virginia, Cara Marie Muscio

Biological Sciences Theses & Dissertations

Lake Prince and the Western Branch Reservoir are two eutrophic bodies of water located in Suffolk, Virginia. Lake Prince and its two small tributaries join the Western branch via a constructed spillway. This lake system is a source of water for the surrounding municipalities, and a recreational area for community citizens. In the past, these bodies of water had repeated incidents of low oxygen and nuisance algal blooms, particularly cyanobacteria species. As a result aerators have been installed in the main body of both Lake Prince and the Western Branch Reservoir. In addition, a pipeline has been installed from North …