Fresh Water Studies Commons^™

Microplastic Composition And Exposure Pathways In Freshwater Systems: A Multi-Matrix Comparison Between Streams And Retention Ponds In Hamilton County, In, Mya Whaley

All-Inclusive List of Electronic Theses and Dissertations

Since the early 1900s, the use of plastics has increased exponentially. The breakdown of plastic materials has exposed all ecosystems to microplastics (small particles of plastic < 5 mm), which are now ubiquitous in natural settings. Microplastics have a relatively large surface area, and many chemicals adsorb to these small particles, impacting their fate and transport of pollution. While microplastics have been found in virtually every setting on Earth, research is necessary to understand their impact on freshwater ecosystems and biogeochemical cycles. The focus of this research was to investigate microplastic compositions in crayfish, sediments, and water samples collected in streams and retention ponds. We analyzed trends in microplastic counts across different land-cover classes, waterbody types, and species, and compared concentrations among matrices to improve our understanding of microplastic exposure pathways in freshwater ecosystems. As a secondary objective, lead and arsenic concentrations were analyzed from sediment samples to investigate metal burdens and compare them to microplastic concentrations. Our findings revealed that, in general, urban streams had the highest microplastic concentrations within land cover categories, and retention ponds had higher microplastic counts than streams. Crayfish, such as F. rusticus had higher microplastic concentrations than F. virilis and F. propinquus, although these results may be influenced by study design. The most common microplastic type was fibers, and most common color was transparent. There was no significant correlation between microplastic and metal concentrations in sediments. We found crayfish to be adequate bioindicators of microplastic pollution, because they were less impacted by environmental variability than sediment and water samples. This research presents the first evidence of microplastics in our study species, F. propinquus, F. rusticus, and F. virlis. This work presents new evidence of microplastic accumulation in crayfish, sediments, and water from freshwater systems in the Midwestern United States. Microplastics were found in every sample type—crayfish, water, and sediment—across urban, rural, and forested landscapes, highlighting their pervasive distribution. The findings provide foundational data for assessing emerging ecological and human-health risks and emphasize the importance of sustained monitoring and research on MP contamination in freshwater environments.

Using Stable Isotope Analysis To Investigate The Trophic Ecology Of Aquatic Insects, Shelby Ann Medlock

Master's Theses

Despite their abundance on the landscape, ponds and associated macroinvertebrate assemblages have largely been underrepresented in scientific studies, which usually focus on lakes or streams. Similar to other waterbodies, ponds can harbor high levels of invertebrate biodiversity, which is important as aquatic insects are experiencing declines due to habitat destruction, pollution, climate change, and invasive species introductions. To evaluate how these threats impact pond insects and the ecosystem services they may provide, a thorough understanding of their ecology is essential. However, significant knowledge gaps remain, especially regarding trophic levels and species-specific diets. To address these knowledge gaps, I used carbon …

Dam It All: A Multi-Scalar Investigation Into The Ecological Role And Function Of Beaver Dams, Kenneth Larsen

Dissertations, Master's Theses and Master's Reports

The central theme of this dissertation is ecological scaling, which examines how small, localized features, such as beaver ponds, contribute to large-scale watershed processes and how different modeling approaches at various scales reveal distinct insights. Through a combination of probabilistic modeling and high-resolution empirical research, this work demonstrates that small ponded systems, particularly those created by beavers (Castor canadensis), serve as critical biogeochemical control points, whose contributions to sediment and nutrient dynamics have been historically underestimated.

In Chapter 1, I contextualize this research within the broader fields of freshwater ecology, watershed modeling, and ecological restoration. I introduce the …

Comparing Metabolism And Hypoxia Tolerance Of Native And Non-Native Florida Freshwater Fishes In Climate Change Scenarios, Benjamin A. Share

All HCAS Student Capstones, Theses, and Dissertations

As climate change brings rising water temperatures and lower dissolved oxygen (DO) concentrations to freshwater bodies, it has become increasingly important to understand how this will affect ecosystems with established non-native or invasive species. Fishes of the family Cichlidae are the most pervasive non-native fishes in the Everglades and may increase their range further north under a changing climate. To better understand potential invasibility and competition with native fishes, the metabolism and hypoxia tolerance of non-native Blue Tilapia Oreochromis aureus was compared to native Bluegill Lepomis macrochirus when acclimated across a range of seasonal and projected temperatures. Intermittent-flow respirometry was …

Investigating Nekton Response To Changing Salinities In The Mississippi Sound: An Experimental And Statistical Approach, Adam Murray

Master's Theses

The Mississippi Sound provides nursery habitats for many coastal species and is recognized for its commercial fisheries. Previous freshening events linked to the Bonnet Carré Spillway, a Mississippi River flood diversion structure, proved catastrophic for oyster populations in the Mississippi Sound, but effects on mobile fish and shellfish species are not well-defined. The planned Mid-Breton Sediment Diversion (MBSD), an initiative to combat wetland loss, is also forecasted to lower salinities in the region, increasing the need to better understand responses of commercially and ecologically important species to freshening events. The objective of this study was to characterize effects of salinity …

Carbon Restoration Potential On Global Land Under Water Resource Constraints, Shouzhang Peng, César Terrer, Benjamin Smith, Philippe Ciais, Qinggong Han, Jialan Nan, Joshua B. Fisher, Liang Chen, Lei Deng, Kailiang Yu

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Ecosystem restoration is a critical nature-based solution to mitigate climate change. However, the carbon sequestration potential of restoration, defined as the maximum achievable carbon storage, has likely been overestimated because previous studies have not adequately accounted for the competition between ecosystem water demands for maximizing carbon sequestration and human water needs. Here we used a comprehensive process-based model combined with extensive land-use data and evaporation recycling accounting for land–atmosphere feedback to estimate the water requirements associated with ecosystem restoration. We found that achieving the carbon sequestration potential of restoration would significantly reduce global water availability per capita by 26%, posing …

Trophic Niche Of A Nonnative Invader And Environmental Drivers Of Its Increasing Populations In The Coastal Everglades, Grace Kahmann, Jennifer S. Rehage, Jordan A. Massie, James A. Nelson, Rolando O. Santos, Natasha M. Viadero, W. Ryan James, Ross E. Boucek, Derek P. Crane, Ryan J. Rezek

Marine Science

The Florida Everglades is a critically important, but highly threatened ecosystem that is becoming increasingly susceptible to the invasion of non-native species. This study investigated the ecological role of the invasive peacock eel (Macrognathus siamensis) within this ecosystem using 15 years of electrofishing data and stable isotope analysis. We investigated the population trends of peacock eels at the marsh-mangrove ecotone of the Shark River Estuary, the environmental factors contributing to their abundance, and the potential interactions they may have with native fish assemblages and coastal food webs. We used stable isotope analysis to provide insights into the basal resource contribution …

Effects Of Microplastic Biofilms On An Anthropogenically Impacted Suburban Lake, Paris M. Velasquez

Masters Theses

Plastics have been observed in every location on the planet, and their prevalence in the environment is due in part to their strong resistance to degradation. Inland lakes are susceptible to plastic pollution by highway runoff, which contains plastic fragments of brake pads, car tires, litter, and road paint. These plastics eventually enter freshwater environments and degrade into microplastics (

Microplastic Accumulation In The Marsh Periwinkle (Littoraria Irrorata), Sarah Keaton, Hannah Lukhard, Eli Windy, Manar Hasan

DePaul Discoveries

Contamination of oceans by microplastics (mm) currently poses a major threat to aquatic and terrestrial ecosystems worldwide. Recent attention towards this issue has raised questions about the extent to which microplastics have accumulated in the environment, and has led to an increase in studies on the effects of microplastics in various organisms. However, levels of contamination in protected natural areas are still largely unexplored, yet can offer an important empirical perspective on the issue. In addition, little is known about the potential effects of microplastics on behavior in the field. This research was conducted within the protected ACE Basin National …

The Ecosystem As Super-Organ/Ism, Revisited: Scaling Hydraulics To Forests Under Climate Change, Jeffrey D. Wood, Matteo Detto, Marvin Browne, Nathan J.B. Kraft, Alexandra G. Konings, Joshua B. Fisher, Gregory R. Quetin, Anna T. Trugman, Troy S. Magney, Camila D. Medeiros, Nidhi Vinod, Thomas N. Buckley, Lawren Sack

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Classic debates in community ecology focused on the complexities of considering an ecosystem as a super-organ or organism. New consideration of such perspectives could clarify mechanisms underlying the dynamics of forest carbon dioxide (CO₂) uptake and water vapor loss, important for predicting and managing the future of Earth's ecosystems and climate system. Here, we provide a rubric for considering ecosystem traits as aggregated, systemic, or emergent, i.e., representing the ecosystem as an aggregate of its individuals, or as a metaphorical or literal super-organ or organism. We review recent approaches to scaling-up plant water relations (hydraulics) concepts developed for …

Evaluating Novel Approaches For Improving Anadromous Fish Passage In Coastal Rivers, Aaron Bunch

All Dissertations

Few of the world's rivers remain free-flowing for over 1000 km, significantly impacting anadromous fish populations due to dam-induced habitat fragmentation. Three partial migration barriers (low-head dams) on North Carolina's Cape Fear River (USA)—lock and dam 1 (LD1), lock and dam 2 (LD2), and lock and dam 3 (LD3)—impact American shad Alosa sapidissima, Atlantic sturgeon Acipenser oxyrinchus oxyrinchus, and striped bass Morone saxatilis populations. Mitigation strategies to pass fish upstream have included conservation locking, nature-like fishway construction, and environmental flows (e-flows). This study introduced a novel e-flow (dam submergence flow), tested acoustic double-tagging techniques for tracking American …

Variations In Salinity And Forest Structure Between Marginal And Cloistered Mangrove Forests In Boca Del Drago, Bocas Del Toro, Panama, Mary Elizabeth Hodge

Independent Study Project (ISP) Collection

Mangroves are incredibly important ecosystems that have an outsized impact on their surroundings, providing crucial ecosystem services like carbon sequestration and coastal protection. At the same time, mangroves are some of the most threatened habitats due to their valuable position along tropical coastlines. Globally, mangrove forests are deforested and degraded by aquaculture, tourism developments, urbanization, and overharvesting. Due to high rates of mangrove loss, mangrove deforestation is now illegal in Panama, though this legislation is inconsistent and allows for exceptions, especially in tourism developments. This study aims to probe the impacts of localized coastal developments on a small mangrove forest …

Examining Bigheaded Carp Ichthyoplankton Drift In Tributary And Mainstem River Systems Of Two Midwestern Rivers, Adam Landry

Masters Theses

The bigheaded carp invasion in North America continues to negatively impact ecosystems making it essential to understand their reproductive dynamics at various spatial scales. Previous studies have highlighted the suitability of tributaries of large rivers for bigheaded carp reproduction, and the importance of tributaries for ichthyoplankton drift to mainstem rivers. This study investigated patterns in tributary-mainstem ichthyoplankton drift dynamics in two invaded river systems of the Midwestern United States, with distinct hydrology, the Illinois and Wabash Rivers. From May-September 2021, I sampled ichthyoplankton from three tributaries and three mainstem sites in each river basin. I analyzed bigheaded carp egg and …

Patterns In Winter Stonefly Distribution Along A River Continuum And Land-Use Gradient In Northwest Arkansas Streams, Zachary Tipton

Graduate Theses and Dissertations

Freshwater ecosystems are facing a crisis with extinction rates of aquatic species exceeding those of their terrestrial counterparts by up to fivefold. This decline is predominantly attributed to evolving land use patterns within watersheds, leading to chemical and physical transformations in freshwater habitats. Northwest Arkansas (NWA) represents one of the fastest-growing regions in the United States, undergoing substantial shifts in land use. Consequently, the status of aquatic life in this region remains uncertain. Addressing this concern, the latest Arkansas Wildlife Action Plan emphasizes the necessity of distribution and population data to guide conservation efforts for Species of Greatest Conservation Need …

The Effects Of Temperature And Flooding Duration On The Structure And Magnitude Of A Floodplain Prey Subsidy, Ryan J. Rezek, Jordan A. Massie, James A. Nelson, Rolando O. Santos, Natasha M. Viadero, W. Ryan James, Ross E. Boucek, Jennifer S. Rehage

Marine Science

Riverine floodplains serve as an important link between terrestrial and aquatic systems, as the rising and falling of water drive spatial food web subsidies that are critical to the functioning and stability of ecosystems. As these systems are increasingly impacted by hydrological alterations and climate change, it is important to understand how floodplain spatial food web subsidies may respond to changing environmental conditions.

Here, we examine the interannual variation in the structure of a sunfish (Lepomis spp.) prey subsidy from freshwater marshes into the mangrove-lined creeks of Rookery Branch in the Florida Coastal Everglades that occurs during seasonal dry downs. …

Mixing Regimes In A Cluster Of Seven Maar Lakes In Tropical Monsoon Asia, Milette U. Mendoza, Jaydan I. Aguilar, Karol Sophia Agape R. Padilla, Rey Donne S. Papa, Noboru Okuda

Environmental Science Faculty Publications

The 7 maar lakes of San Pablo are a cluster of small volcanic lakes on Luzon Island; Philippines. These lakes; which are heavily utilized for aquaculture and ecotourism; usually experience fish kills that coincide with the northeast monsoon (NEM). This study explores limnophysical processes; particularly mixing regimes; in the lakes in relation to prevailing monsoons. We monitored monthly vertical and seasonal profiles of water temperature; salinity; conductivity; and dissolved oxygen from October 2016 to December 2018. Three types of mixing regimes were observed among the lakes; which have similar surface areas but different depths: polymixis in the shallowest; warm monomixis …

Climate Warming Amplifies The Frequency Of Fish Mass Mortality Events Across North Temperate Lakes, Simon P. Tye, Adam M. Siepielski, Andrew Bray, Andrew L. Rypel, Nicholas B.D. Phelps, Samuel B. Fey

Biological Sciences Faculty Publications and Presentations

Recent increases of animal mass mortality events have coincided with substantial changes in global climate. Yet, tractable approaches that predict how climate change will accentuate occurrences of these ecological catastrophes remain nascent. We compiled one of the most comprehensive datasets of lentic fish mortality events, thermal tolerances of affected families, and 1.2 million air and water temperature profiles across 8891 north temperate lakes in North America. Temperature extremes within and across lakes were strongly associated with the three most frequent cause types (infectious agents, summerkills, winterkills). Thermal tolerances mediated the lethality of direct thermal stress, but mortalities of warm- and …

How Flow Regime Affects Predator-Prey Relationships Of Stream Darter And Shiner Species, Anna E. Richardson

Biological Sciences Undergraduate Honors Theses

Analysis of the interactions between abiotic and biotic factors of environments and ecosystems is a highly valued area of research. This study focuses on the interactions between the biotic component of predation and foraging of certain stream fish species and the abiotic component of the flow regime that those species reside in. Gut content analysis followed by statistical calculations in the form of t-tests and chi -quared tests were performed on two fish species who both inhabited a stream with a groundwater flashy flow regime as well as a stream with a runoff flashy flow regime. The research showed that …

Phragmites Australis Dieback In The Mississippi River Delta: Chemical Profiles Of Soil Types And Restoration Potential, Herie Lee

LSU Master's Theses

Since 2016, there has been widespread dieback of P. australis in the Lower Mississippi River Delta (hereafter referred to as Lower MRD, which is defined as the Birds Foot Delta) with relatively little to no signs of recovery. The cause of the current dieback is not fully understood. This thesis explores P. australis with emphasis on chemical profile characterization of different soil types and its effects on plant growth and the potential for restoration in the Lower MRD.

In chapter 2, I characterized the chemical profiles of soils collected from healthy and dieback stands of Phragmites, and from newly …

Plant Community Response To The Combined Effects Of Elevation, And Simulated Nutrient And Sediment Loading In Sagittaria Lancifolia-Dominated Wetlands, Donnie Day

LSU Master's Theses

Coastal wetlands are experiencing threats to their long-term sustainability brought about by the combined effects of relative sea-level rise and human modifications to hydrology, sediment delivery and nutrient loading. Restoration and management strategies can include adding sediment to the surface of deteriorating marshes to facilitate positive feedbacks among elevation, plant productivity, sediment trapping, and accretion; however, if delivered using nitrate-enriched river waters, belowground biomass and soil organic matter pools may be negatively affected, resulting in the acceleration of wetland loss. Overall, there is limited information on the combined effects of nutrient loading, sedimentation, and flooding dynamics in regulating feedbacks among …

Picking Up Where The Tmdl Leaves Off: Using The Partnership Wild And Scenic River Framework For Collaborative River Restoration, Alan R. Hunt, Meiyin Wu, Tsung-Ta David Hsu, Nancy Roberts-Lawler, Jessica T. Miller, Alessandra Rossi, Lee Lee

Department of Biology Faculty Scholarship and Creative Works

The National Wild and Scenic Rivers Act protects less than ¼ of a percent of the United States’ river miles, focusing on free-flowing rivers of good water quality with outstandingly remarkable values for recreation, scenery, and other unique river attributes. It predates the enactment of the Clean Water Act, yet includes a clear anti-degradation principle, that pollution should be reduced and eliminated on designated rivers, in cooperation with the federal Environmental Protection Agency and state pollution control agencies. However, the federal Clean Water Act lacks a clear management framework for implementing restoration activities to reduce non-point source pollution, of which …

Aquatic Macrophyte Communities In Five Sibley County (Minnesota) Lakes And The Factors That Affect Their Distribution, Samuel A. Schmid

All Graduate Theses, Dissertations, and Other Capstone Projects

The purposes of this study are to 1) quantify the shifts in the macrophyte community structure of five lakes in Sibley County, and 2) to assess the relationships between the macrophyte communities and abiotic factors in these five lakes. In both the early and late growing season of 2019, point-intercept surveys were conducted on High Island Lake, Titlow Lake, Schilling Lake, Silver Lake, and Clear Lake. At each point, water depth was recorded, and all macrophytes sampled were identified and recorded as “present.” There was not a late season survey conducted for High Island Lake in 2019 due to a …

Paleoenvironmental Reconstruction Of Quaternary Saltville, Virginia, Using Ostracode Autecology, Austin Gause

Electronic Theses and Dissertations

The Saltville valley in southwestern Virginia is home to Quaternary localities containing paleontological and archaeological remains. Historically the valley has been mined for salt and the small lakes, ponds and springs along the valley floor have a brackish signature. A preliminary report on the site’s ostracode fauna suggested that the site’s water was not always saline. This study analyzed modern and Quaternary ostracodes to understand the valley’s hydrologic and chemical evolution. Sediments contained primarily freshwater species, including the environmentally sensitive Candona crogmaniana. The presence of Pelocypris tuberculatum and a new Fabaeformiscandona species throughout a vertical section spanning the latest Pleistocene …

A Framework For Aquatic Invasive Species Surveillance Site Selection And Prioritization In The Us Waters Of The Laurentian Great Lakes, Andrew J. Tucker, W. Lindsay Chadderton, Gust Annis, Alisha D. Davidson, Joel Hoffman, Jon Bossenbroek, Stephen Hensler, Michael Hoff, Erika Jensen, Donna R. Kashian, Sarah Lesage, Timothy Strakosh

Environmental Science and Geology Faculty Research Publications

Risk-based prioritization for early detection monitoring is of utmost importance to prevent and mitigate invasive species impacts and is especially needed for large ecosystems where management resources are not sufficient to survey all locations susceptible to invasion. In this paper we describe a spatially-explicit and quantitative approach for identifying the highest risk sites for aquatic invasive species (AIS) introduction into the United States’ waters of the Laurentian Great Lakes, a vast inland sea with a surface area of 246,049 square km and a shoreline length of 16,431 km. We compiled data from geospatial metrics available across all of the US …

Spatial And Temporal Genetic Structure Of Winter-Run Steelhead (Oncorhynchus Mykiss) Returning To The Mad River, California, Steven R. Fong

Cal Poly Humboldt theses and projects

Distinct populations of steelhead in the wild are in decline. The propagation of steelhead in hatcheries has been used to boost population numbers for recreational fisheries and for use in conservation. However, hatchery breeding practices of steelhead can result in changes in genetic structure. I investigated the genetic structure of winter-run steelhead (Oncorhynchus mykiss) returning to the Mad River, California, where a hatchery has been used enhance production for recreational fisheries since 1971. Genetic variability in Mad River steelhead was evaluated using 96 single nucleotide polymorphisms (SNPs) among 4203 individuals, including the Mad River and nearby locations, and …

Assessing The Hierarchy Of Long-Term Environmental Controls On Diatom Communities Of Yellowstone National Park Using Lacustrine Sediment Records, Victoria Chraibi, Sherilyn C. Fritz

Department of Earth and Atmospheric Sciences: Faculty Publications

An ecosystem’s ability to maintain structure and function following disturbance, defined as resilience, is influenced by a hierarchy of environmental controls, including climate, surface cover, and ecological relationships that shape biological community composition and productivity. This study examined lacustrine sediment records of naturally fishless lakes in Yellowstone National Park to reconstruct the response of aquatic communities to climate and trophic cascades from fish stocking. Sediment records of diatom algae did not exhibit a distinct response to fish stocking in terms of assemblage or algal productivity. Instead, 3 of 4 lakes underwent a shift to dominance by benthic diatom species from …

A Delicate Balance: The Effects Of Habitat Type On Frog Communities: A Three-Pronged Study Examining The Effects Of Differing Habitat Characteristics On Anuran Diversity At El Centro De Investigación Sumak Kawsay In Situ, Ecuador, Zane Libke

Independent Study Project (ISP) Collection

We conducted 60 hours of visual encounter surveys and 3 hours of calling surveys on 6 different habitat types near Sumak Kawsay in situ Reserva (SKIS) near Mera, Pastaza, Ecuador. We defined habitat types defined by two variables: type of forest and proximity to water. The aim of the study was to determine what effect each variable has on anuran community composition. We compared the effectiveness of the two survey methods as well. High anuran community dissimilarity was found between each habitat type surveyed, indicating that both forest type and proximity to water are important factors that shape species richness …

Amphibian And Reptile Community Responses To Forest And Riparian Disturbance, Jacquelyn Christine Guzy

Graduate Theses and Dissertations

Riparian zones are transitional, semi-terrestrial areas regularly influenced by freshwater. These areas serve as dispersal corridors for many animal and plant species and ultimately function as important reservoirs of biodiversity in altered landscapes. While much of the riparian habitat in the United States has been affected by anthropogenic activities, management actions may mitigate potentially negative influences of these activities. For example, Streamside Management Zones (i.e., riparian buffers; SMZs) are commonly implemented within managed forests to protect water quality, but may also provide habitat for riparian-associated wildlife. Yet, little research has rigorously addressed the value of SMZs for wildlife, particularly cryptic …

A Long-Term (2002 To 2017) Record Of Closed-Path And Open-Path Eddy Covariance Co2 Net Ecosystem Exchange Fluxes From The Siberian Arctic, David Holl, Christian Wille, Torsten Sachs, Peter Schreiber, Benjamin R. K. Runkle, Lutz Beckebanze, Moritz Langer, Julia Boike, Eva-Maria Pfeiffer, Irina Fedorova, Dimitry Y. Bolshianov, Mikhail N. Grigoriev, Lars Kutzbach

Biological and Agricultural Engineering Faculty Publications and Presentations

Ground-based observations of land–atmosphere fluxes are necessary to progressively improve global climate models. Observed data can be used for model evaluation and to develop or tune process models. In arctic permafrost regions, climate–carbon feedbacks are amplified. Therefore, increased efforts to better represent these regions in global climate models have been made in recent years. We present a multi-annual time series of land–atmosphere carbon dioxide fluxes measured in situ with the eddy covariance technique in the Siberian Arctic (72◦220 N, 126◦300 E). The site is part of the international network of eddy covariance flux observation stations (FLUXNET; site ID: Ru-Sam). The …

Evaluation Of An Educational Campaign To Improve The Conscious Consumption Of Recreationally Caught Fish, Corey A. Krabbenhoft, Susan Manente, Donna R. Kashian

Environmental Science and Geology Faculty Research Publications

Consumption guidelines are a common way of improving conscious consumption behaviors in areas where game fish are known to contain contaminants. However, guideline information can be difficult to distribute, and effectiveness difficult to measure. To increase the distribution and effectiveness of guideline information for the Detroit River, an educational campaign was launched in 2010, which included distribution of pamphlets with consumption information, posting of permanent signs at popular fishing locations, and hiring River Walkers to personally communicate with anglers. In 2013 and 2015, we conducted in-person surveys of active shoreline anglers to determine the effectiveness of education and outreach efforts. …