Life Sciences Commons^™

Drivers And Dynamics Of Phytoplankton Communities And Harmful Algal Blooms In Mountain Lakes, Lara Stephanie Jansen

Dissertations and Theses

Harmful cyanobacterial blooms (cyanoHABs) are a complex and widespread disturbance in freshwater water bodies, impacting water quality for wildlife and human populations. While cyanobacteria often bloom in warm lakes impacted by human development like agriculture, blooms are increasingly reported in cooler waters with limited development in the surrounding watershed. As much of cyanoHAB research has focused on lakes in highly developed watersheds, the understanding of factors leading to cyanobacteria dominance and blooms in the absence of major development remains limited. Mountain lakes can serve as ideal systems to study bloom-forming cyanobacteria in watersheds with minimal development. In addition, mountain lakes …

The Effects Of Variations In Light And Nutrient Availability On Phytoplankton And Zooplankton, Jake Anthony Swanson

Theses and Dissertations

Aquatic ecosystems experience a wide range of variation in resource availability; two of the resources that are most essential to phytoplankton and zooplankton are light and nutrients. Light can vary in both its color and intensity; these variations can directly impact phytoplankton by altering the amount and color of light available for photosynthesis. Nutrient variability, particularly increases in nutrient levels, also alter phytoplankton communities by favoring the growth of certain taxa such as cyanobacteria.

To understand whether phytoplankton respond differently to changes in light availability I investigated whether the diversification of cryptophytes, phytoplankton with diverse light-capturing pigments, showed evidence of …

The Impact Of Nutrient Depletion On The Effect Of Hhq On Emiliania Huxleyi, Marley Gonsalves

Honors Theses and Capstones

Emiliania huxleyi is a ecologically important, bloom-forming coccolithophore. HHQ is a bacteria compound that causes cell stasis in E. huxleyi that can lead to bloom termination. This study analyzed the role that nutrient depletion plays in this relationship. Results show that nitrogen depletion protects cells from the effects of HHQ, affecting bloom dynamics.

The Toxicity Of Dopamine On Salish Sea Phytoplankton, Allyson Lombardo

WWU Graduate School Collection

In the Salish Sea, blooms of the intertidal macroalgae, Ulvaria obscura, are common and can achieve extraordinarily high biomass. Upon desiccation and subsequent rehydration from incoming tides, U. obscura releases dopamine. Previous studies showed that dopamine negatively affects other macroalgal species and can deter grazers. However, the effects of dopamine on co-occurring phytoplankton remains unknown. This study explored the toxicity of dopamine on four phytoplankton known to inhabit the Salish Sea: the haptophyte, Isochrysis galbana; the chlorophyte, Dunaliella tertiolecta; the dinoflagellate, Heterocapsa triquetra; and the diatom, Thalassiosira sp. Over the course of 8 days, phytoplankton growth …

Interactions Between Juvenile Estuary-Dependent Fishes And Microalgal Dynamics, Ian C. Williams

USF Tampa Graduate Theses and Dissertations

The ontogenetic movement of juvenile estuary-dependent fishes upstream in estuarine settings is a phenomenon observed around the world. These movements usually coincide with a shift in diet from smaller prey, such as calanoid copepods, to larger prey, such as mysids. However, the mechanism that drives this pattern has yet to be conclusively described. Prior to the current study, zooplankton/hyperbenthos (“zooplankton”), primary production, and water quality data were collected from the Caloosahatchee River estuary in two concurrent and coordinated studies over a two-year period. One of the products of these sampling efforts was a classification of primary-producer types at the sediment-water …

Construction Of Dichotomous Taxonomic Keys For San Francisco Bay Planktonic Diatoms, Ria Angelica Laxa

Undergraduate Honors Theses

Planktonic diatoms exhibit high biodiversity in marine systems and make a significant contribution to water column primary productivity. This makes research on planktonic diatoms particularly important in measuring the health of coastal marine ecosystems. At the University of San Francisco (USF), undergraduate research has been conducted since September 2015 to study planktonic diatoms in San Francisco Bay. A previous study by Keith (2018), Planktonic Diatom Species Succession in San Francisco Bay, documented changes in species diversity over time, observing seasonal patterns in species richness as well as the effect of environmental factors such as salinity, temperature, and rainfall on species …

Bloom Or Bust: Search For Phytoplankton Community Drivers Using Long-Term Time-Series Observations And Field Measurements In A Model Great Lakes Estuary, Jasmine Mancuso

Masters Theses

As sentinels of climate change and other anthropogenic effects, freshwater lakes are experiencing ecosystem disruptions at every level of the food web, beginning with the phytoplankton. One of the major threats to waterbodies around the world are cyanobacterial harmful algal blooms (HABs) resulting from anthropogenic eutrophication and exacerbated by climate change. Muskegon Lake, a drowned river mouth Great Lakes estuary on the east coast of Lake Michigan, is no exception and was declared an Area of Concern by the EPA in 1987 with nuisance algal blooms cited as a beneficial use impairment. Using long-term data and additional 2019 sampling, we …

Plankton Dynamics In An Urban, Subtropical Lake Prior To Lake Restoration, Jennifer C. Pulsifer

LSU Master's Theses

This research assessed plankton dynamics in two urban, subtropical lakes (University Lake and City Park Lake) shortly before a proposed and approved lake restoration project. Plankton dynamics were determined in University Lake by the dilution method to attempt to quantify growth rates of phytoplankton and grazing rates of zooplankton. Landry and Hassett’s (1982) dilution method has been widely used in marine systems to estimate rates of growth and grazing. In many marine systems, nutrients must be added to prevent nutrient limitation. However, it is assumed, due to the hypereutrophic conditions, that nutrients would not be a limitation in University Lake. …

Diatom Community Responses To Development And Climate Change In Lake George, An Oligotrophic Lake In The Adirondack Mountains, Adam T. Ruka

Masters Theses

Lake George is a highly monitored, oligotrophic lake that experiences widespread tourism in the summer months. The southern basin is more developed than the northern basin, suggesting a north-south gradient of anthropogenic impairment. This study aimed to assess differences in nearshore diatom communities regarding gradients of water chemistry and watershed development throughout the lake. Using Redundancy analyses, water chemistry was found to explain more variation within diatom assemblages than watershed variables. Weighted averaging optima and tolerances specified taxa of concern, F. gracilis and A. formosa, that indicate increased phosphorus (μg/L) and conductivity (μS/cm), respectively. Two hypotheses related to the effect …

Assessing The Competitive Advantage Of Carbonic Anhydrase In Estuarine Microalgae Through Removed Enzymatic Activity, Eilea R. Knotts

Theses and Dissertations

Carbon concentrating mechanisms (CCMs) are used by photoautotrophs to overcome possible limitations in carbon acquisition but the competitive strategies and efficiencies of these mechanisms among photosynthesizers can be variable. The diversity in carbon acquisition abilities establishes the potential for alterations in community structure with shifting carbon concentrations. Given the role of phytoplankton and benthic microalgae (BMA) in the trophodynamics of estuaries, understanding the mechanisms of carbon acquisition in these systems is important in predicting how primary productivity and nutrient cycling might change in response to increasing concentrations of atmospheric CO2. Our approach to investigate whether induced carbon limitation would show …

The Stability Of Temperate Lakes Under The Changing Climate, Aleksey Paltsev

Electronic Thesis and Dissertation Repository

There is a collective prediction among ecologists that climate change will enhance phytoplankton biomass in temperate lakes. Yet there is noteworthy variation in the structure and regulating functions of lakes to make this statement challengeable and, perhaps, inaccurate. To generate a common understanding on the trophic transition of lakes, I examined the interactive effects of climate change and landscape properties on phytoplankton biomass in 12,644 lakes located in relatively intact forested landscapes. Chlorophyll-a (Chl-a) concentration was used as a proxy for phytoplankton biomass. Chl-a concentration was obtained via analyzing Landsat satellite imagery data over a 28-year period (1984-2011) and using …

The Microcystis Microbiome: Interactions With Heterotrophic Bacteria In The Microcystis Phycosphere, Alexa Hoke

Masters Theses, 2010-2019

Harmful algal blooms are a growing problem globally in both freshwater and marine systems. Cyanobacterial harmful algal blooms (cHABs) can have numerous environmental and economic impacts. cHABs can reduce oxygen levels in the water column, ultimately leading to the death of larger organisms, and reduce light penetration, impacting aquatic vegetation. cHABs can also release toxins into the water and efforts to prevent toxins from entering drinking water can cost cities millions of dollars in added filtration. Microcystis is a freshwater cyanobacterium that is globally distributed. While many of the abiotic factors that can impact bloom formation are known, biotic factors, …

Interactive Effects Of Domoic Acid Allelopathy, Salinity, And Eutrophication On Estuarine Phytoplankton Community Structure, Elise Van Meerssche

Theses and Dissertations

Coastal regions and estuaries are particularly sensitive to the increase in nutrient loading and river runoff, threatening the ecosystems with possible spreads in harmful algal blooms (HABs). As an example, blooms of toxic Pseudo-nitzschia species can release acute concentrations of the neurotoxin domoic acid (DA) in the water column. When ingested at concentrations higher than 20 ppm, DA can cause the death of marine birds, marine mammals and even humans. The main objectives of my research were to determine the drivers of Pseudo-nitzschia abundance and toxicity and to assess how these drivers influenced the phytoplankton community structure and DA allelopathy. …

Dna Barcoding Reveals A New Morphotype Of The Sugar Kelp, Saccharina Latissima, Dallin Brimley, Zakery Ford, Travis Gould, Brandon Guerra, Emily Haggett, Ian Jones, Elyse Johnson, Ken Peterson, Matthew Prout

Thinking Matters Symposium Archive

Phytoplankton blooms follow predictable annual cycles in the Gulf of Maine, characterized by a large spring bloom and a smaller bloom in the fall. Marine phytoplankton form the foundation of primary production in Gulf of Maine waters, and thus community changes in composition, and abundance could have cascading effects on our coastal ecosystems.

We set out to monitor the community composition, diversity, and abundance of the spring micro-phytoplankton bloom, at a Friends of Casco Bay water quality monitoring site, in South Portland, Maine. The Gulf of Maine is experiencing accelerated warming rates, and this type of monitoring can aid in …

The Influence Of Juncus-Rhizosphere Dissolved Organic Matter On Coastal Plankton Communities, Brittany Zepernick, Robert Michael Mckay, George S. Bullerjahn, Jeffrey W. Krause, Behzad Mortazavi

Honors Projects

Many aquatic plants produce copious amounts of dissolved organic matter (DOM) which enters surrounding waters and potentially stimulates planktonic activity. In the northern Gulf of Mexico, Juncus roemarianus (i.e. black needlerush) is a dominant marsh grass species residing in coastal zones and barrier islands. The below-ground biomass i.e. rhizosphere, can be consistently submerged, serving as a potential source of DOM to the surrounding waters. The lability and possible stimulatory effect of J. roemarianus DOM was examined for three plankton communities collected within the discharge region of Mobile Bay and adjacent waters of Gulf Shores, Alabama (less affected by Mobile Bay). …

Assessing Biogeochemical Impacts And Environmental Conditions Associated With Cross-Shelf High Chlorophyll Plumes In The Northern Gulf Of Mexico, Erin Brooke Jones

Dissertations

The northern Gulf of Mexico is a complex marine system subject to episodic physical phenomena such as loop current eddies. Flow fields generated by these eddies can result in cross-shelf exchanges between riverine influenced shelf waters and the offshore water column. This study considers the impacts of high chlorophyll plumes (HCPs) resulting from cross-shelf exchanges to the bio-optical properties of affected waters and how these plumes are influenced by their environment. The seasonal, interannual and decadal chlorophyll cycles of the Gulf of Mexico and the northern Gulf of Mexico are described to provide context for evaluating the ecological effects of …

Mathematical Modeling Of Competition For Light And Nutrients Between Phytoplankton Species In A Poorly Mixed Water Column, Thomas George Stojsavljevic

Theses and Dissertations

Phytoplankton live in a complex environment with two essential resources forming various gradients. Light supplied from above is never homogeneously distributed in a body of water due to refraction and absorption from biomass present in the ecosystem and from other sources. Nutrients in turn are typically supplied from below. In poorly mixed water columns phytoplankton can be heterogeneously distributed forming various layering patterns. The relationship between the location and the thickness of the layers is an open problem of interest. Here we present three models which study how competition for light and resources can form common layering patterns seen in …

Benthic And Planktonic Microalgal Community Structure And Primary Productivity In Lower Chesapeake Bay, Matthew Reginald Semcheski

Biological Sciences Theses & Dissertations

Microalgal populations are trophically important to a variety of micro- and macroheterotrophs in marine and estuarine systems. In Chesapeake Bay, microalgae facilitate the survival and development of ecologically and economically relevant fauna, including shellfish and finfish populations. While regarded as significant components of coastal environments, microphytobenthic communities are historically understudied. In Chesapeake Bay, the importance of phytoplankton to the ecosystem is understood, but the contribution of microphytobenthos remains unclear. This project surveys intertidal microphytobenthic communities, in relation to phytoplankton communities, around lower Chesapeake Bay describing the taxonomic makeup of these populations, coupled with quantification of cell abundance, biomass, and primary …

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 …

Freshwater Phytoplankton Populations Detected Using High Pressure Liquid Chromatography (Hplc) Of Taxon-Specific Pigments, Lauren Jeanne Simmons

Theses and Dissertations

Phytoplankton are key primary producers in aquatic ecosystems, and the principle food source for primary consumers. Individual phytoplankton species respond to different physical, chemical and biological parameters, so monitoring taxonomic composition of the phytoplankton community is a means to monitor changes in environmental conditions. Phytoplankton community changes have frequently been monitored by estimating biomass (using chlorophyll a, measured fluorometrically), and taxonomic data obtained from cell counts. While such methods are useful, they are time-consuming. I hypothesized that high pressure liquid chromatography (HPLC) methods, which have been frequently used in marine systems, would allow separation and identification of key pigments. …

Ocean Acidification: Understanding The Coastal Carbon Pump In A High Co2 World, Rachel Cooper

Theses and Dissertations

Since the 1800s, carbon dioxide emissions due to human activities have contributed significantly to the amount of carbon in the atmosphere. Approximately a third of this carbon is absorbed by the ocean, through air-sea fluxes at the ocean surface (Sabine, 2004). Increased CO2 has changed the carbon chemistry of the ocean and hence the pH. pH is expected to drop by 0.4 by the year 2100. It is unclear how this lower pH will affect carbon cycling and sequestration with respect to the biological carbon pump. Most studies have focused on open ocean phytoplankton or bacterial communities in large, stationary …

Novel Methodology For Assessing Phytoplankton Response To Pco2 Enrichment In Fresh And Saltwater, Susan B. Gifford

Theses and Dissertations

Atmospheric CO2 emissions are on the rise and are expected to reach 780 parts per million by the year 2100. Research investigating the impacts of increasing CO2 is a relatively new field and the response of phytoplankton communities is largely unknown, especially in coastal and freshwater ecosystems where no CO2 manipulation studies have completed. The present study attempts to encourage uniformity in methods utilized in CO2 perturbation studies and identifies changes in phytoplankton abundance in freshwater (James River) and coastal ocean (Atlantic, Cape Hatteras) sites. A novel bubbling method to manipulate pCO2 was compared with the classic method of acid …

Factors Influencing The Abundance, Community Composition And Activity States Of Bacterioplankton From The Tidal Freshwater James River, Catherine Luria

Theses and Dissertations

Aquatic bacteria respond to changing environmental conditions through a variety of mechanisms including changes in abundance, shifts in community composition and variable activity states. In the tidal-freshwater James River, variation in bacterial abundance was linked to nutrient availability and autochthonous production with highest bacterial densities associated with low-nutrient, high-chlorophyll a conditions. Laboratory experiments revealed that bacterial growth rates were nutrient limited at the low-nutrient site, while co-limitation (nutrients, glucose, light) was apparent at the high nutrient site. Despite large differences in abundance, community composition was similar based on TRFLP and 16S rDNA pyrosequencing. Community similarity was lower among rRNA libraries …

Zooplankton Abundance, Community Composition And Grazing In The James River Estuary (Virginia, Usa), Laura E. Barry

Theses and Dissertations

This study examined the extent to which zooplankton in the James River Estuary (Virginia, USA) exploit the available algal-food resources. Zooplankton abundance, community composition and grazing rates were assessed at three locations which included a site with high algal production (near the VCU Rice Center) and two sites where algal production was lower. Grazing rates were measured by determining the rate of phytoplankton decline (as chlorophyll a) during 48-hour incubation experiments in the presence and absence of zooplankton. Significant differences in zooplankton abundance were observed among the three sites, with the greatest average zooplankton density (434 ± 69 ind/L) occurring …

Coupling Of Autotrophic And Heterotrophic Plankton Food Web Components In The Tidal-Freshwater James River, Usa, Matthew Beckwith

Theses and Dissertations

Empirical studies have shown that algal- and detrital-based food web components are coupled in many pelagic systems as algal carbon enhances bacterioplankton production and growth efficiencies. Such phyto-bacterioplankton coupling impacts carbon flow through plankton food webs, yet the extent of coupling is poorly understood in systems receiving large amounts of allochthonous carbon. To investigate this issue, bacterioplankton abundance (BA) and community composition were compared to chlorophyll a concentrations and phytoplankton production in the tidal-freshwater James River (VA). BA averaged 107 cells mL-1 and was significantly related to chlorophyll a, phytoplankton production, and DOC concentrations. Analysis of DOC quality using fluorescence …

The Spatial Distribution Of Phytoplankton In Westhampton Lake, Richmond, Virginia, James William Newlin

Master's Theses

The hypothesis is that spatial distributions of phytoplankton standing crop and photosynthetic capacity in Westhampton Lake are homogeneous was tested. Distributions were analyzed with respect to horizontal and vertical planes separately and combined. The study was divided into three time period: 1) late summer stratification, 2) early fall mixing, and 3) fall turnover, based on isothermal lines of the lake at the deepest station. Phytoplankton standing crop was measured by spectrophotometric and fluorometric methods. The photosynthetic capacity was measured flurometrically. Combined horizontal and vertical spatial distribution of standing crop was clumped for the entire lake and during each time period. …

The Use Of Track Autoradiography To Determine Species-Specific Phytoplankton Productivity, Ralph Martin Vaga

Dissertations and Theses

Methods of measuring primary productivity are discussed in terms of what information they provide concerning energy flow in the phytoplankton community. A track autoradiographic technique is presented which measures species-specific phytoplankton productivity and its use is demonstrated under laboratory conditions. Controls and standardized processing conditions are established which permit the use of the track technique in quantitative evaluations of primary productivity.

Phytoplankton Composition At Lake Drummond In The Dismal Swamp, Virginia, William Howard Poore Jr.

Biological Sciences Theses & Dissertations

Abstract unavailable.

The Phytoplankton Of The Logan River, Utah, A Mountain Stream, William J. Clark

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The voluminous limnological literature contains few studies of mountain streams. Though there are a few papers on the benthic algae (see Budde 1928, Raabe 1951) only Pennak (1943) reports year-round quantitative data on the phytoplankton. Brinley (1950) gives some phytoplankton information in a summer study of streams in Rocky Mountain National Park.