Terrestrial and Aquatic Ecology Commons^™

Seasonal Dynamics And Trends Of Environmental Conditions In Lake Louise, Georgia, Daniel Kwawuvi, James A. Nienow

Georgia Journal of Science

Lakes are important aquatic ecosystems that are extensively influenced by seasonal variations. In this study we investigate the seasonal dynamics and trends of three environmental variables, water temperature, conductivity and dissolved oxygen (DO), in Lake Louise, a sinkhole lake located in southern Georgia. These variables were measured in-situ along a depth profile from January 27, 2024 to January 17, 2025. We also accessed archived data from field campaigns in 2003, 2004, and 2017 in order to test whether a recent increase in the number of hurricanes impacting the region, five since August, 2017, may have significantly altered the seasonal dynamics …

Modeling Upper Ocean Ecosystem Dynamics In Response To Interannual Sea-Ice Variability In The Western Antarctic Peninsula, Catherine R. Czajka, Jessica S. Turner, Sharon Stammerjohn, Heather H. Kim, Oscar Schofield, Benjamin T. Saenz, Scott C. Doney

OES Faculty Publications

In the Western Antarctic Peninsula (WAP), marine plankton dynamics are tightly linked to the interannual variability in environmental conditions, including phenological shifts in sea-ice seasonality. To explore these linkages, we use a 1-dimensional vertical ocean-ice-ecosystem model (KPP-Eco-Ice, or KEI) that simulates physical and ecosystem conditions at a continental shelf mooring location in the Palmer Long Term Ecological Research program sampling grid. KEI allows for year-round examination of the ecosystem in a region where in situ observations on the shelf are limited to January. Comparisons are made between seasonal sea-ice retreat, mixed layer depth, primary productivity, and phytoplankton relative abundance, grazing, …

Investigating Drivers In Phytoplankton Between Lentic And Lotic Ecosystems Within Twelvepole Creek Watershed, Devin Lee Farmer

Theses, Dissertations and Capstones

Harmful Algal Blooms (HABs) threaten aquatic ecosystems, local economies, and water quality. While extensively studied in lakes (lentic systems), their impact on flowing waters (lotic systems) remains underexplored. This study examined algal drivers in both ecosystems within the same watershed, focusing on Beech Fork Lake (lentic) and Twelve Pole Creek (lotic). Key environmental factors, including pH, turbidity, dissolved oxygen, and nutrient levels, were measured using in situ sensors and laboratory analysis. Water samples were analyzed for nitrogen, phosphorus, and algal biomass for comparison to environmental conditions. Phytoplankton was preserved for identification in future research. By comparing these environments, this study …

Phytoplankton Community Dynamics In The Northern California Current System, Kristin Forgrave

Student Research Symposium

The Northern California Current system is a productive coastal ecosystem that encompasses a variety of temporal and spatial features. The photosynthetic microbial community plays a crucial role in supporting the rich ecosystem and economically important fisheries. My research integrates data across distance and two years to investigate the community composition of two major phytoplankton groups in this system: picocyanobacteria and picoeukaryotes. The abundances and sizes of the phytoplankton were measured using flow cytometry. Picoeukaryotes were found to be present at similar concentrations in both summer and winter. Abundances of both cell types were comparable in the winter, but picocyanobacteria were …

Submarine Groundwater Discharge As A Major Nutrient Source In River-Fed Vs. Tidally Dominated Estuaries, Stephanie J. Wilson, Joseph J. Tamborski, Bongkeun Song, Peter Bernhardt, Margaret R. Mulholland

OES Faculty Publications

The tidal tributaries of the lower Chesapeake Bay experience seasonally recurring harmful algal blooms and the significance of submarine groundwater discharge (SGD) as a nutrient vector is largely unknown. Here, we determined seasonal SGD nutrient loads in two tributaries with contrasting hydrodynamic conditions, river-fed (York River) vs. tidally dominated (Lafayette River). Radon surveys were performed in each river to quantify SGD at the embayment-scale during spring and fall 2021. Total SGD was determined from a ²²²Rn mass balance and Monte Carlo simulations. Submarine groundwater discharge rates differed by a factor of two during spring (Lafayette = 11 ± 17 cm …

Exploring The Relationship Between Dreissenids And The Deep Chlorophyll Layer In The Laurentian Great Lakes, Lara E. Hargrave

Great Lakes Center Masters Theses

In the Laurentian Great Lakes, two invasive bivalves Dreissena polymorpha and Dreissena rostriformis bugensis have induced a number of changes, including increased water transparency, alterations in nutrient cycling, decreased chlorophyll concentrations, and changes in phytoplankton community composition and structure. These changes are likely to have implications for the deep chlorophyll layer (DCL), a feature characterized by phototrophic organisms reaching abundance at light levels far below ideal for photosynthesis. Though the impacts of D. polymorpha and D. r. bugensis in the Great Lakes have been studied for at least the last three decades, little is known about how these ecosystem engineers …

The Importance Of Winter Dinoflagellate Blooms In Chesapeake Bay— A Missing Link In Bay Productivity, Nicole C. Millette, Sophie Clayton, Margaret R. Mulholland, Leah Gibala-Smith, Michael Lane

OES Faculty Publications

It is widely assumed that phytoplankton abundance and productivity decline during temperate winters because of low irradiance and temperatures. However, winter phytoplankton blooms commonly occur in temperate estuaries, but they are often undocumented because of reduced water quality monitoring in winter. The small body of in situ work that has been done on winter blooms suggests they can be of enormous consequence to ecosystems. However, because monitoring is often reduced or stopped altogether during winter, it is unclear how widespread these blooms are or how long they can last. We analyzed an over 30-year record of monthly phytoplankton monitoring samples …

Atmospheric Input And Seasonal Inventory Of Dissolved Iron In The Sargasso Sea: Implications For Iron Dynamics In Surface Waters Of The Subtropical Ocean, Peter N. Sedwick, Bettina M. Sohst, K. N. Buck, S. Caprara, R. J. Johnson, D. C. Ohnemus, L. E. Sofen, A. Tagliabue, B. S. Twining, Tara E. Williams

OES Faculty Publications

Constraining the role of dust deposition in regulating the concentration of the essential micronutrient iron in surface ocean waters requires knowledge of the flux of seawater-soluble iron in aerosols and the replacement time of dissolved iron (DFe) in the euphotic zone. Here we estimate these quantities using seasonally resolved DFe data from the Bermuda Atlantic Time-series Study region and weekly-scale measurements of iron in aerosols and rain from Bermuda during 2019. In response to seasonal changes in vertical mixing, primary production and dust deposition, surface DFe concentrations vary from ∼0.2 nM in early spring to >1 nM in late summer, …

A Global Comparison Of Marine Chlorophyll Variability Observed In Eulerian And Lagrangian Perspectives, Angela M. Kuhn, Matthew Mazloff, Stephanie Dutkiewicz, Oliver Jahn, Sophie Clayton, Tatiana Rynearson, Andrew D. Barton

OES Faculty Publications

The California Current System is a diatom‐dominated region characterized by seasonal coastal upwelling and additional elevated mesoscale activity. Cyclonic mesoscale eddies in the region trap productive coastal waters with their planktonic communities and transport them offshore with limited interaction with surrounding waters, effectively acting as natural mesocosms, where phytoplankton populations undergo ecological succession as eddies age. This study examines diatom community composition within two mesoscale cyclonic eddies that formed in the same region of the California Current System 2 months apart and in the California Current waters surrounding them. The diatom communities were analyzed in the context of shifting environmental …

Resolving The Drivers Of Algal Nutrient Limitation From Boreal To Arctic Lakes And Streams, Maria Myrstener, Megan Fork, Ann-Kristin Bergstrom, Isolde Callisto Puts, Demian Hauptmann, Peter D. F. Isles, Ryan M. Burrows, Ryan A. Sponseller

Biology Faculty Publications

Nutrient inputs to northern freshwaters are changing, potentially altering aquatic ecosystem functioning through effects on primary producers. Yet, while primary producer growth is sensitive to nutrient supply, it is also constrained by a suite of other factors, including light and temperature, which may play varying roles across stream and lake habitats. Here, we use bioassay results from 89 lakes and streams spanning northern boreal to Arctic Sweden to test for differences in nutrient limitation status of algal biomass along gradients in colored dissolved organic carbon (DOC), water temperature, and nutrient concentrations, and to ask whether there are distinct patterns and …

Uncoupled Seasonal Variability Of Transparent Exopolymer And Coomassie Stainable Particles In Coastal Mediterranean Waters: Insights Into Sources And Driving Mechanisms, Marina Zamanillo, Eva Ortega-Retuerta, Carolina Cisternas-Novoa, Cèlia Marrasé, Carles Pelejero, Josep Pascual, Josep M. Gasol, Anja Engel, Rafel Simó

Research outputs 2014 to 2021

Transparent exopolymer particles (TEP) and Coomassie stainable particles (CSP) are gel-like particles, ubiquitous in the ocean, that affect important biogeochemical processes including organic carbon cycling by planktonic food webs. Despite much research on both groups of particles (especially TEP) over many years, whether they exist as distinctly stainable fractions of the same particles or as independent particles, each with different driving factors, remains unclear. To address this question, we examined the temporal dynamics of TEP and CSP over 2 complete seasonal cycles at 2 coastal sites in the Northwestern Mediterranean Sea, the Blanes Bay Microbial Observatory (BBMO) and the L’Estartit …

Contrasting Patterns Of Nutrient Limitation In The Littoral And Pelagic Zones Of Mesotrophic Maine Lakes, Grace C. Neumiller

Honors Theses

Intense nutrient loading of nitrogen (N) and phosphorus (P) causes sudden regime shifts in freshwater ecosystems from clearwater to turbid conditions with frequent cyanobacterial blooms. Characterization of nutrient limitation patterns of primary productivity in these ecosystems is necessary for effective management of algal blooms. However, much of this research has focused on pelagic habitats. The influence of lake habitat (i.e. benthic littoral versus pelagic zones) on nutrient limitation of primary production in mesotrophic lakes is largely unknown, particularly in contrast to research on pelagic nutrient limitation in eutrophic systems. Using paired nutrient diffusing substrata and mesocosm experiments, we measured chlorophyll- …

Water Quality Assessment In The Occurrence Of Acanthaster Spp. (Crown-Of-Thorns Starfish, Cots) On Coral Reefs In Menjangan Island, Bali, Indonesia, Novia Arinda Pradisty, Eghbert Elvan Ampou, Rizki Hanintyo

Makara Journal of Science

Aquatic stressors are known to cause biological impairment that can result in biodiversity loss in several Marine Protected Areas (MPA), including in Menjangan Island, West Bali National Park. The objectives of this study were to correlate the changes in water quality parameters with the biological effect of Crown-of-Thorns starfish (CoTS) population dynamics and to assess the most applicable parameters for continuous environmental monitoring. Field observations and surveys were conducted three times in 2017, during the wet season, dry season and season transition, in order to assess the effect of seasonal variability. Redundancy Analysis (RDA) was performed to determine the relationship …

Surface Levels, Keisha Brathwaite

Electronic Theses and Dissertations

Surface Levels are depictions of unobserved and imperceptible realities of many phytoplankton exteriors. The exhibition explores various structures, textures, and repetitious forms from microscopic surfaces of objects that cannot be seen with unaided eyes. Electron microscopy is used to perceive and analyze these otherwise unseeable surfaces in depth. Magnifications provide a reference in creating three- and two-dimensional works that are minimalistic and abstract at a visible level. This abstract 3D/2D image collection is translated into material expressions using acrylic sheets, acrylic ink, and wood as the main media for construction of individual works. Collectively, they serve to make the invisible …

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. …

Role Of Coastal Environmental Conditions During Austral Winter On Plankton Community Dynamics And The Occurrence Of Pseudo-Nitzschia Spp. And Domoic Acid In Inhambane Province, Mozambique, Holly Kelchner

LSU Master's Theses

Harmful algal blooms (HABs) are increasing globally in frequency, persistence, and geographic extent. HABs pose a threat to economic stability, and ecosystem and human health. To date no incidences of marine toxins produced by phytoplankton have been recorded in Mozambique, which may be due to the absence of a monitoring program and general awareness of the potential threat. This study is the first documentation of the occurrence of a neurotoxin, domoic acid (DA), produced by the diatom genus Pseudo-nitzschia spp. along the east coast of Africa. The coast of Inhambane Province is a biodiversity hotspot where year-round Rhincodon typus (whale …

Surfacant Contamination Alters Freshwater Phytoplankton Community Composition, William H. Hodge

College of Graduate Studies: Theses & Dissertations

Pollution from cleaning and personal care products enter freshwater systems and have the potential to alter phytoplankton abundance and diversity. Alkyl polyglucoside (APG), a widely used foaming agent in detergents, decreases phytoplankton abundance, but whether sensitivity to APG is affected by taxonomic identity and/or the presence of competitors is unclear. Establishing taxon-specific responses to APG is important, because taxa differ in nutritional quality and palatability for zooplankton grazers.

Chapter one describes comparisons between how individual phytoplankton communities respond to the same range of APG concentrations to test hypotheses that: 1) chemical concentration determines how individual taxa respond to APG; 2) …

Short Term Effects Of Hurricane Irma On The Phytoplankton Of Lake Louise, Georgia, Usa, Marque'l K. Gould, Adam J. Nienow, Anastasia V. F. Nienow, James A. Nienow

Georgia Journal of Science

Natural disturbances such as fires and severe storms can have profound impacts on the hydrology and ecology of inland waters, potentially altering the structure and function of the ecosystem for extended periods of time. Studies of the initial impacts are, however, uncommon. Here we report on the short-term impacts of Hurricane Irma in the structure of the phytoplankton association in Lake Louise, a small blackwater lake in southern Georgia. Irma hit the region on September 11, 2017, with tropical storm force winds. The event corresponded to a period during which we were conducting routine weekly monitoring of environmental conditions in …

Effects Of Invasive Watermilfoil And Seasonal Dynamics On Primary Production In Littoral Zones Of North-Temperate Lakes, Ryan R. Van Goethem

Dissertations, Master's Theses and Master's Reports

Climate change and species invasion are two agents of global change altering aquatic ecosystems worldwide. Submerged aquatic macrophytes control lake ecosystem processes through their direct and indirect interactions with other primary producers, but how their interactions may be altered by species invasions or how they function over full seasonal cycles in temperate lakes is poorly understood. We first addressed whether the presence of invasive watermilfoil (IWM) altered standing crops and gross primary pro-duction (GPP) of other littoral primary producers (macrophytes, phytoplankton, attached algae or periphyton) in littoral zones of 6 Michigan lakes. We found no differences in primary producer standing …

Nutrient Limitation Of Algal Growth In Fishery Lakes, Madeline Ludwig

Biological and Agricultural Engineering Undergraduate Honors Theses

This study investigated the effect of nutrient addition on algal growth in three United States Forest Service lakes for fishery management in Arkansas. In fishery managed lakes, fertilization works by manipulating algae growth, a basal food resource in lakes, to promote the growth of the fish population. For the nutrient addition experiments, water was collected from each lake in cubitainers and spiked with nutrients; the treatments included the control, nitrogen (+N), phosphorus (+P), and nitrogen and phosphorus (+N +P). When algal growth was visually observed, a water sample was collected from each cubitainer and analyzed for chlorophyll-α. The results showed …

Sea Surface Temperature Rises Shift Migration Patterns Due To Ecosystem Changes, Alexia Skrbic, Hesham El-Askary

Student Scholar Symposium Abstracts and Posters

The continuing climate change is negatively impacting ecosystems, specifically oceans which are declining and food webs are being altered by the increase of greenhouse gases. The increase of the carbon dioxide and other greenhouse gases is increasing sea surface temperature of the world’s oceans. Certain organisms lower on the food chain like phytoplankton and zooplankton are directly affected by the warming which alters how they process nutrients and their productivity. The limited amount of these primary producers in the oceans and specifically the location they inhabit directly affects all the organisms above them on the food chain. Several marine animals …

How The Presence Of Plastic In The North Pacific Gyre Affects The Growth Of Thalassiosira Through Remote Sensing And Laboratory Replication, Jordynn Brennan, Hesham El-Askary

Student Scholar Symposium Abstracts and Posters

Through the use of remote sensing, we are able to determine the approximate location of the garbage patch in the North Pacific Gyre. Though remote sensing does not penetrate the surface of the ocean, monthly satellite images can be analyzed to determine the rate of growth or rate of decrease of certain parameters, such as atmospheric gases, phytoplankton, and dissolved organic matter. Over the past decade, data from the Goddard Earth Sciences Data and Information Services Center (Giovanni program) has shown a significant increase in dissolved organic matter and chlorophyll a content in the area of the North Pacific Garbage …

The Role Of Nitrogen And Phosphorus In The Growth, Toxicity, And Distribution Of The Toxic Cyanobacteria, Microcystis Aeruginosa, James Parrish

Master's Projects and Capstones

Microcystis aeruginosa is among the most common harmful algal-blooming species in the world. Potent microcystins released by M. aeruginosa have been linked to liver failure and death in aquatic mammals, like the endangered California sea otter, and provide a serious public health risk to humans. Once characterized as a freshwater problem, M. aeruginosa is expanding on a global scale, making persistent returns in freshwater, brackish, and coastal marine ecosystems. Though commonly observed dominating aquatic ecosystems in low N:P atomic ratios less than 44:1, the reliability of N:P ratios as a tool for managing and predicting M. aeruginosa blooms is explored …

A Survey Of Aquatic Invertebrate Communities In Nebraska Sandhill Lakes Reveals Potential Alternative Ecosystem States, J.C. Jolley, E.S. Albin, M.A. Kaemingk, D.W. Willis

Natural Resource Management Faculty Publications

Aquatic invertebrate communities are important to shallow lake ecosystem form and function, providing vital components to the food web and thereby important to achieving lake management goals. We characterized lake invertebrate communities and physicochemical variables in six Nebraska Sandhill lakes and examined these characteristics within an alternative stable state framework. Surveys were conducted during 2005 within each of these lakes by sampling aquatic macroinvertebrate abundance, zooplankton abundance and biomass, phytoplankton biomass, and physicochemical variables. When placed within an alternative stable state framework, the response variables exhibited a gradient of different ecosystem states. Two lakes appeared congruent with the clear water …

Harmful Algal Bloom (Hab) Communities And Co-Occurring Species In Relation To Near Shore Ocean Dynamics In San Luis Bay, California, Samuel Christopher Rankin

Master's Theses

The occurrence of phytoplankton taxa, with special focus on harmful algal bloom (HAB) taxa, was monitored for one year off the central coast of California to examine both their co-occurrence and physical and chemical variables influencing their temporal patterns. Bi-weekly samples were taken from October 6, 2008 to October 5, 2009 in San Luis Obispo Bay, CA. Canonical correspondence analysis (CCA) of weekly samples indicated that 46.1% of the variability in species abundance was explained by the variables in the model, higher than previous reports. Cluster analysis divided phytoplankton communities into HAB and non-HAB groups of species, while shared distribution …

Preliminary Ecological Assessment Of Stream Quality In The Sacramento Mountains, New Mexico., Ector M. Martell^, Bianca C. Luong^, Vanessa Lougheed*

COURI Symposium Abstracts, Spring 2011

Pollution in freshwater ecosystems has reduced the ability of freshwater habitats to host a variety of organisms. Algal biomass and macroinvertebrate assemblages can reflect stream quality, due to their rapid response to nutrients and limited dispersal ability, respectively. In this study, we used algae and macroinvertebrates as bio-indicators of river quality in the Sacramento Mountains of New Mexico, which is largely forested with some low-level development and cattle grazing. All of our sites (n = 3) had a macroinvertebrate Ephemeroptera, Plecoptera, Trichoptera (EPT) index of 50% or greater, which suggest high quality conditions in the river. More specifically, all sites …

Modeling Algae Self-Replenishment, V. S. Manoranjan, Miguel A. Olmos Gomez, R. Corban Harwood

Faculty Publications - Department of Mathematics

This paper presents a sunlight-dependent algae growth model. Driven by the circumstances surrounding Lake Chapala, Mexico, this theoretical model is an endeavor to understand the resilient sustainability of algae that threatens the area’s ecosystem. In this paper, free-floating algae (phytoplankton) are treated as two distinct populations according to their location in the body of water: the vibrant sunlit upper region and the stagnate lower region where photosynthesis is not possible. The numerical solution for the model is analyzed and results are discussed in light of previous studies and the state of Lake Chapala.

Invasive Predator, Bythotrephes, Has Varied Effects On Ecosystem Function In Freshwater Lakes, Angela L. Strecker, Shelley E. Arnott

Environmental Science and Management Faculty Publications and Presentations

Bythotrephes longimanus is an invertebrate predator that has invaded the North American Great Lakes and a number of inland lakes, where it preys on crustacean zooplankton. We examined the effect of Bythotrephes on two measures of ecosystem function during a four month observational study of freshwater lakes on the boreal shield. Bythotrephes-invaded lakes had significantly lower epilimnetic zooplankton abundance and production compared to reference lakes. On average, Bythotrephes consumed 34% ofzooplankton production when it was present in lakes. There was some evidence of changes in the timing of zooplankton production, as well as shifts to cooler, less productive habitats, which …

Seasonal And Spatial Distribution Of Phytoplankton In The Waters Off Nuclear Power Plants, North Of Taiwan, Wen-Tseng Lo, Jiuan-Jiuan Hwang, Pei-Kai Hsu, Hung-Yen Hsieh, Yueh-Yuan Tu, Tien-Hsi Fang, Jiang-Shiou Hwang

Journal of Marine Science and Technology–Taiwan

Species composition of phytoplankton was monitored seasonally in the waters off the First and Second Nuclear Power plants (NPP1 and NPP2), north of Taiwan during 2001-2002. In total, 290 phytoplankton samples were collected and 265 taxa of phytoplankton were recorded. Chaetoceros compressus, Pseudo-nitzschia delicatissima, Skeletonema costatum, Thalassionema nitzschioides, and Lauderia annulata were the top five dominant species. Together they comprised 75% of the total phytoplankton cells. The species number and abundance of phytoplankton showed distinct seasonal, annual, and spatial changes, higher abundance in 2002 than 2001 and highest in August in both years and lowest in March in 2001 and …