Authors: Courtney Cooper and Berry College Student Team

Poster Abstract:

With southeastern waterways facing intensifying environmental challenges, Indigenous knowledge offers essential insights into conservation, stewardship, and long-term watershed resilience. The Coosa River Basin Initiative (CRBI) podcast Downstream: Indigenous Perspectives on Conservation features Cherokee and Muscogee leaders whose stories illuminate ancestral understandings of ecological change and contemporary water issues. In this poster, we describe how students in Southeast Water Policy helped transform the nine-episode podcast series into adaptable classroom materials. Using active and experiential learning approaches, we worked with students to refine curriculum modules, draft discussion questions, and design in-class activities that deepen engagement with Indigenous perspectives on water governance. During class sessions, students applied these materials through structured discussions and hands-on exercises that connect podcast themes to regional water policy. Our goal is to provide learners with a multimodal, culturally grounded way to understand water conservation while amplifying Indigenous voices in environmental policy education. As the curriculum is finalized, we will develop complementary assessment tools to evaluate how effectively these materials support student learning about Indigenous perspectives on watershed stewardship.

Groundwater availability in fractured crystalline rock aquifers is notoriously heterogeneous, complicating efforts to identify optimal well locations for domestic and agricultural supply. This study presents a spatially integrated groundwater suitability model for the Georgia Piedmont/Blue Ridge region, developed using a multi-criteria weighted overlay analysis in a GIS environment. Ten thematic layers, Slope, Drainage Density, Distance to Streams, Lineament Density, Distance to Geologic Contacts, Lithology, Hydrologic Soil Group, Available Water Storage (0–150 cm), Land Cover (NLCD), and a derived Groundwater Potential Surface, were standardized to a standard scale (1–5) and weighted based on hydrogeologic significance. Lineaments were manually digitized and merged with smoothed NHD flowlines to capture both large-scale fractures and stream-aligned structural features. The resulting composite raster was classified into five groundwater suitability zones using natural breaks (Jenks). Model accuracy was evaluated by comparing raster scores to observed well yields (n ≈ 1,497), with statistical assessments including correlation coefficients and box-and-whisker plots. While the correlation coefficient (r ≈ 0.05) was low, suggesting a weak linear relationship, median yield values increased in higher suitability classes, validating the model’s heuristic structure. This approach offers a scalable method for groundwater targeting in data-sparse, structurally complex terrains. It provides local planners and well drillers with a relative framework for siting high-yield wells.

Poster Authors:

Courtney E. Fouke, Tayton Alvis, Jamie L. Rogers, Dustin J. Benton, Jewell L. Johnson, Carla L. Atkinson, Nicholas S. Marzolf

Poster Abstract:

The southeastern US is a freshwater biodiversity hotspot in North America, particularly among invertebrates and mollusks. Freshwater gastropods play important structural and functional roles in rivers, but there are limited studies about their natural history and abundance. We aimed to describe the distribution of freshwater snails in a tributary of the Lower Flint River watershed in southwest Georgia. We surveyed ten shoals in the lower reaches of Ichawaynochaway Creek in late summer 2025 to determine the species composition, abundance, and habitat associations of freshwater snails. At each shoal, we conducted 15 five-minute snorkel visual surveys using a transect-quadrat method across a 25-m reach. For the dominant species, Elimia boykiniana, we measured the individual snail shell short and long axis dimensions, axes of the operculum, and wet mass. Additionally, we characterized substrate, velocity, and depth at each quadrat, and water physical chemistry (dissolved oxygen, temperature, pH) at each shoal. We identified three snail taxa: E. boykiniana (n = 1804), Family Hydrobiidae (n = 327) and Viviparus goodrichi (n =1), but focused on E. boykiniana as it was the most abundant taxa. E. boykiniana shell length (2.0-18.6mm), wet mass (0.0061-1.8g), and mean density per shoal (0.5-135.8 snails/m2) varied across shoals. E. boykiniana density decreased as water deepened across the shoals, but the density-velocity relationship was site-specific. For substrate preference, snail density was greater on bedrock relative to cobble, sand, and wood habitats. Overall, our results indicated that E. boykiniana density is influenced by habitat characteristics within this specific creek. These findings offer an insight into the freshwater gastropod community in Ichawaynochaway Creek to inform future conservation and monitoring efforts in the southeast USA.

Poster Authors: Carlie Blackburn, Dr. Steven Brantley, Dr. Frances O'Donnell

Poster Abstract:

Geographically isolated wetlands (GIWs) are a common landscape feature in the lower Apalachicola-Chattahoochee-Flint basin. GIWs are known for the abundance of ecosystem services they provide including water filtration, sediment and nutrient retention, and water storage which can help mitigate both floods and droughts. While GIWs are overall beneficial, their role in watershed hydrology remains unclear. For example, it is generally unknown how much water is used by vegetation in these wetlands compared to other land cover types, or to potential evapotranspiration (PET). This project will investigate the evapotranspiration (ET), above ground net primary productivity (NPP), and water use efficiency (WUE) of two relatively undisturbed geographically isolated wetlands (GIWs) on The Jones Center at Ichauway, Newton GA. These wetlands lack surface connections to other water bodies, and hydrology is predominantly driven by rainfall and subsurface flow. Quantifying these three variables will give us a better understanding of water use and associated ecosystem services. ET was measured every 30 minutes using the Li-Cor 710 evapotranspiration sensor. Leaf level WUE of dominant plant species was assessed using the Li-Cor 6400 gas exchange system. Above ground productivity was quantified through clip plot sampling, and through applying a weighted WUE value to the ET data to get sub-daily NPP. We found that wetland ET was near zero in winter, rapidly increased in April, and was highest in the summer months (June-August). Temporal variations in ET were driven by net radiation and phenology of dominant vegetation. WUE varied substantially by species. Species furthest from the wettest and deepest point of the wetland were more water use efficient than those located at the deepest point creating a range of diversity throughout these ecotones. While we found 35 species within the wetland boundary, productivity was dominated by broomsedge (Andropogon virginicus) around the relatively dry outside rim. Further analysis will examine the potential role of different vegetation types in maintaining wetland productivity while reducing ET, protecting two key functions of wetlands. These findings help inform us of GIWs' ecological role within the landscape to help us enhance management strategies to better protect and conserve these ecosystems.

Poster Authors: L. Caitlin Sweeney
 Katelyn B. Herman
 Stephen W. Golladay

Poster Abstract:

A Habitat Conservation Plan is being developed for six species of freshwater mussels in the lower Flint River Basin (see ga-fit.org/hcp/). Four of the listed species (Alasmidonta triangulata, Amblema neislerii, Elliptoideus sloatianus, and Hamiota subangulata) are known to occur in the mainstem Flint, but the mainstem had not been comprehensively surveyed since 2011. Since 2023, we have performed 41 surveys in the Flint River to update the distribution and abundance of species in a ~100km mainstem segment between Bainbridge and Albany, GA. Originally, sites were selected based on ease of access and location of historical data. As we gained understanding of the species’ habitat preferences in the Flint, we began to use more systematic approaches to select sites. Online aerial imagery from a period of low discharge aided in identifying shoals and sandy banks. Additionally, a collaboration with Georgia Aquarium’s Research & Conservation team and their scientific divers provided access to deeper areas of the river that we could not properly survey with our standard snorkel methods. With our survey data, we show that the four listed species still occur within the lower Flint mainstem with E. sloatianus being the most abundant and widely distributed. Plotting our data spatially, we show that the listed species are being found in different longitudinal zones throughout the mainstem, and we extend the known distribution of A. triangulata and A. neislerii. We are using this information to develop priority areas for surveys in 2026.

Poster Authors: Laila Racevskis, Amy Bainbridge,
Dan Dourte, and Wendy-Lin Bartels, The Balmoral Group

Poster Abstract:

To assist with improving collaboration and coordination among the many entities working to manage the natural systems within the Apalachicola River and Bay System, the Apalachicola Watershed Coordination Blueprint Project (AWCB) was initiated to create a trusted source of information in the watershed and to improve how interested parties work together within the watershed. The project has utilized a combination of methods to achieve these goals, including an inventory of interested parties; management and restoration plan review; multiple workshops and individual expert interviews; data compilation and analysis; literature and funding repository development; and the development of numerous online resources.
Results of the work to date include identification of restoration priorities, gaps, needs, resources, and team-building approaches for restoration projects and established an advisory committee to facilitate collaboration and project development for Coastal Habitat, Hydrologic, and Upland Habitat Restoration focus areas. An online AWCB Information Hub has been created that provides maps, data, and other resources related to restoration projects, interested parties, literature, agency reports, funding opportunities, and other information relevant to ecological restoration activities and needs in the watershed. A Collaboration Workspace has also been created to provide a dedicated site for collaboration, resource and information-sharing, and building teams to pursue funding. The poster will summarize the resources developed for the project and share insights and best practices for collaborative ecological restoration by highlighting innovative ecological restoration and conservation partnerships, projects, and resources in the watershed.

Poster Authors: Laura Wenk and Caroline Cox

Poster Abstract:

Striped Bass (Morone saxatilis) populations in the ACF (Apalachicola River, Chattahoochee River, and Flint River) are unique and vulnerable primarily due to the presence of man-made barriers. These barriers block this naturally cool-water species from moving through the riverine environment to colder areas during summer months. Despite restricted connectivity to upstream cool water habitat, in the ACF, this species persists by utilizing the many spring outflows along the river. These springs provide thermal refuge to striped bass and many other species by maintaining water temperatures in the 60s. During warm summer months, striped bass move into the springs in the Flint River to avoid water temperatures exceeding 73°F. These fish are trapped in these cool water outflows and are fully dependent on them for refuge. With fish congregated in the springs during this time (May-October) there is a unique opportunity for GA DNR to monitor these fish and get a rough estimate of recruitment and population size.

Poster Authors: Stephen Golladay, Georgia Water Planning and Policy Center

Caitlin Sweeney, Jones Center at Ichauway

Poster Abstract

A Habitat Conservation Plan is being developed for six species of freshwater mussels in the lower Flint River Basin (LFRB, see ga-fit.org/hcp/). Two of the listed species (Hamiota subangulata and Pleurobema pyriforme) are known to occur in Spring Creek, the southernmost major tributary. We used historic (1999, 2012, 2014) and recent (2023-2025) sampling data from two segments (lower, upper) of the creek to evaluate changes in the abundance and distribution of listed species, mussel assemblage composition, and species richness. All data were standardized to represent equivalent sampling effort and expressed as numbers per 25 m of stream length (representing 187.5 m2 area searched). An extended period of below-normal rainfall, including 3 multiyear droughts, occurred between 2000-2012. During this period 11 of 13 years had 1-day minimum discharge of less than the monthly 10th percentile including 5 years where streams ceased flowing (0 CFS). Beginning in 2013, drought conditions relaxed and stream discharge returned to more moderate levels, particularly during the growing season. Across all years, the upper segment of Spring Creek consistently had the greatest numbers of listed species, total mussel abundance, and species richness. Increases in abundance and distribution of listed species were observed with the relaxation of drought flows. H. subangulata appears to have responded rapidly to favorable conditions being observed throughout the upper and lower segments of Spring Creek. P. pyriforme has also expanded its distribution but is still only detected in the upper segment. Multiple size classes (including juveniles) of both listed species have been documented suggesting recent reproduction. Our results suggest that conservation strategies aimed at reducing the intensity, duration, or frequency of extreme low flows will likely benefit mussel populations in Spring Creek.

Poster Authors: Eric Walther, Matthew Rowe, and Seth Wenger

Poster Abstract: Freshwater mussels are among the most imperiled taxa globally, but conservation efforts are impeded by a paucity of empirical information on the dynamics of most populations. The lower Flint River basin supports a rich diversity of freshwater mussels, of which 10 are state protected and 5 have federal protection status under the Endangered Species Act. In recent decades, the region has experienced severe, recurring droughts along with an increased demand for water to support agriculture, industrial expansion, and urban development. These conditions have caused mass mortality events in listed mussels in the Lower Flint in the past and have raised concerns about the future potential impact of extreme low streamflow conditions on mussel populations. Beginning in 2005, the Georgia Department of Natural Resources has conducted annual monitoring surveys for freshwater mussels at five stream reaches in the lower Flint River basin (n = 14 – 19 surveys) during which 21 species and over 20,000 animals have been observed. This dataset provides an exceptional opportunity to evaluate the effects of river flow on mussel population dynamics. For each reach, we grouped the counts of mussels into three categories–equilibrium, periodic and opportunistic¬¬ strategists–based on life history traits. We then calculated annual growth rate for each group. We fit univariable linear regression models for 116 flow metrics that were calculated using nearby USGS stream gages to assess non-mutually exclusive hypotheses about how hydrology affects growth rates of each group. For each season (i.e., spring, summer, winter), we identified the hydrologic conditions that best explained variation in growth rate and predicted expected growth rates over the range of observed flow conditions. Ultimately, understanding the relationship between mussel populations dynamics and streamflow conditions will be an important component for effective mussel conservation and water planning in the region.

Poster Authors: Authors: James E. Hawkins III^1,2 Carla L. Atkinson¹, Nicholas S. Marzolf², Taylor C. Michael¹, Matthew B. Lodato¹, and Lauren M. Morris¹

1. University of Alabama, Tuscaloosa, AL, USA.
2. The Jones Center at Ichauway, Newton, GA, USA.

Poster Abstract: Freshwater mussels can influence ecosystem processes by removing particles from the water column through filtration and altering nutrient availability through excretion. Variation in functional traits (e.g., body size, metabolic rates) and soft-tissue stoichiometry among mussel species is expected to produce differences in nutrient recycling and particle dynamics. We investigated interspecific variation in clearance and excretion rates among five native unionoid mussel species (Amblema plicata, Lampsilis ornata, Pleurobema decisum, Pustulosa kieneriana, and Tritogonia verrucosa) in the Sipsey River, Alabama, a river that supports high mussel density and diversity.

We quantified mass-specific clearance rates and particle size distributions using short-term field incubations and Flowcam analysis. We estimated species-specific excretion rates of inorganic nutrients (ammonium [NH4+] and soluble reactive phosphorus [SRP]) using short-term field incubations.

Preliminary results suggest species-specific differences in mass-specific clearance rates and dissolved nutrient recycling. Smaller species exhibited greater clearance rates than larger species, and species differed in the size distributions of particles removed, indicating species-specific filtering on suspended particulate structure. Mass-specific nutrient excretion rates also varied among species: SRP excretion rates differed marginally among taxa, with both Pleurobema decisum and Pustulosa kieneriana exhibiting greater excretion rates than other species. NH4+excretion rates were marginally significantly different across species. These patterns are consistent with variation in functional traits among taxa and suggest species identity influences dissolved nutrient recycling and particulate dynamics within river systems.

Overall, our findings highlight how functional differences among mussel species can alter nutrient cycling and particulate flux, with potential implications for the nutrient availability, downstream sediment dynamics, and energy flow in freshwater rivers. This is particularly relevant as unionid populations continue to decline in freshwater systems.

Poster Authors: Elizabeth Sicking, Kier Klepzig, Steve Golladay, Daniel McLaughlin, Sally Entrekin

Poster Abstract: Less frequent but more intense precipitation events and increasing water demand are altering hydrological norms in the southeast US. Geographically isolated wetlands (GIWs) are a common feature across the southeast that vary in hydrological characteristics, vegetation type, and productivity. Despite their typically small size and lack of continuous surface connectivity, GIWs are important habitat for macroinvertebrate communities that contribute to regional biodiversity and provide high-quality food resources for aquatic and upland consumers. GIWs also provide ecosystem services by filtering and slowing the entrance of excess nutrients, sediments, and other contaminants into the underlying aquifer. The extent that long-term hydrology and other factors influence macroinvertebrate community dynamics and other GIW processes is relatively unknown, making it difficult to understand how changes in hydrological patterns may affect GIW communities. To investigate the role of long-term hydrology and vegetation in shaping macroinvertebrate community dynamics, we sampled 11 GIWs located in SW Georgia across the 2023 hydroperiod. We conducted biweekly and monthly sampling to measure macroinvertebrate and emergent insect richness, density, and emergence rates across space and time. Our results indicate that hydrology is the principal determinant of aquatic community dynamics and is closely linked with macroinvertebrate diversity and biomass emergence. Maintaining hydrologic diversity on the landscape should be considered in conservation decisions to support diverse and abundant aquatic insect communities, and ultimately, aquatic and upland food webs. Future work on GIWs in the region will focus on the relationships between hydrology, biogeochemistry, and trophic dynamics ranging from zooplankton community development to aquatic insect nutritional quality and vertebrate predation on aquatic resources.

Poster Authors: Fariha Khan, Dr. Rachel Scarlett

Poster Abstract: Urban streams play a significant role in the transformation and transportation of dissolved organic matter which influences the oxygen demand, nutrient cycling and microbial metabolism in aquatic system. Proctor creek, in particular, collects complex mixtures of organic matter and pollutants from highly urbanized region of Atlanta and drains into Chattahoochee River, impacting the downstream water quality in the Apalachicola–Chattahoochee–Flint (ACF) River Basin. It receives higher proportion of dissolved organic matter (DOM) inputs from residential, commercial, industrial land use than from natural sources and are influenced by frequent runoff events, rapid hydrologic transportation, stormwater infrastructure and sanitary sewer overflows which complicates the biogeochemical processes in the water column. Extra cellular enzyme assay can provide insights into the microbial functions on DOM retention and transformation and nutrient availability in the water column. Extra cellular enzyme assay has been studied widely in the sediment and biofilms but lacks in-depth protocol for water column microbial activities in highly developed watersheds. This project aims to fill the gap by developing a well-structured protocol for conducting microplate fluorometric assay in the water column targeting proctor creek as a representative highly urbanized system. Focusing on the urbanized stream context, the protocol lays the groundwork for measuring microbial community’s role in DOM transformation in the water column. This study contributes to the water quality monitoring initiatives of streams impacted by dynamic urban settings and support future endeavors of aquatic biogeochemical function research in relation to watershed characteristics.

Poster Authors: George Mensah and Rachel D. Scarlett

Poster Abstract: Urban streams operate as natural arteries of the urban watersheds, concomitantly acting as hotspots for organic matter and nutrient loads, widely attributed to urban stormwater runoff. However, freshwaters in heavily modified catchments are complex due to multiple factors influencing water quality, nutrient cycling and aquatic ecosystem health. As a result, the dynamics of dissolved organic carbon (DOC) under stormwater pulses are not well understood. This study investigated the patterns of DOC and total dissolved nitrogen (TDN) loading under baseflow and stormflow conditions in a highly urbanized watershed. We hypothesized that storm events are driving the dynamics of DOC and TDN in urban streams, leading to elevated concentrations, while enhancing DOC quality due to the enrichment of nitrogen solutes.

We tested these hypotheses in a highly urbanized tributary of the Chattahoochee River in West Atlanta, Georgia, during the summer months of 2025. We examined the concentrations of DOC and TDN and computed their stoichiometric ratios to infer OM quality. We examined the concentration-discharge relationship of storm events to define their hysteresis pattern that reflects different transport processes into the stream.

Results indicate temporally decreased DOC and increased TDN concentrations during storm events, suggesting mobilization from different sources. The concentration-discharge relationships were weak and not statistically significant for DOC (r = -0.09, p = 0.33) and TDN (r = -0.09, p = 0.29), implying a dominant chemostatic behaviour and a mixed pool of solutes associated with urban stream syndrome frameworks. Stoichiometric analysis showed no correlation between C:N ratios and discharge (r = -0.02, p = 0.82) despite considerable variability of C:N ratios. This is an indication that DOC quality is not significantly controlled by hydrologic forces, but variability in DOM composition likely reflects heterogenous source contributions. Hysteresis patterns showed a predominance of clockwise loops for DOC, signifying rapid flushing of proximal, carbon-rich sources in the initial stages of storm hydrographs. Weak and inconsistent hysteresis patterns were evident in TDN, suggesting contributions from heterogenous sources and less defined mobilization processes. Our findings suggest a decoupling between hydrology and biogeochemistry in highly urbanized streams, in which engineered drainage systems and anthropogenic sources supersede classical storm-driven influences on solute dynamics.

Poster Authors: Blaire Smith, Dr. Ryan Saylor, Dr. Alice Suroviec, Dr. Dominic Qualley

Poster Abstract:

For decades, plastic has infiltrated some of the world’s most remote environments in unexpected and unprecedented ways. Whether it be run of the mill plastic litter in your backyard, microplastics washing up on the sand, or even running through our own blood, plastic is truly all around us and inside us. Now, plastic being invisible to the naked eye is not necessarily novel, but what about plastic in liquid form? Polyvinyl Alcohol (PVA) is a colorless, odorless, synthetic compound that dissolves in water. However, the compound still remains completely intact, just in aqueous form, and can enter the food chain easily due to its lack of biodegradability. Under normal conditions, the compound does not degrade or break down, but instead remains in the world’s watersheds. Furthermore, PVA has the opportunity to interact with different microbial organisms and oxidation processes, turning it into phthalates. Phthalates are compounds that have been well documented for their adverse effects on the human hormone system. The purpose of this study is to attempt to quantify the amount of PVA present in the Etowah River, and if their presence has crossed the boundary into freshwater organisms present in the Etowah. The Etowah River feeds into the Coosa, one of the most biodiverse rivers in the world. Protecting the Etowah and the Coosa is paramount to ensure biodiversity, endemic species, and even humans continue to thrive.

Poster Authors: Tayton Alvis, Courtney K. Fouke, Jamie L. Rogers, Carla L. Atkinson, Nicholas S. Marzolf

Poster Abstract: Animal consumers contribute to fluxes and ambient pools of key nutrients through excretion and egestion, influencing stream biogeochemical processes. Aggregations of consumers can create hotspots of nutrient cycling due to high areal rates of biological activity. Freshwater snails have the potential to influence ecological processes due to their high abundance and role as primary consumers, yet few studies have attempted to quantify their contributions to nutrient cycling in streams. To understand the role of freshwater snails in nutrient cycling, we are conducting excretion assays with locally abundant Elimia collected from Ichawaynochaway Creek, GA, USA. We will incubate individual snails in 15 mL of filtered stream water for one hour before filtration and analysis for ammonium and soluble reactive phosphorus. We will quantify egestion rates using the mass of egestion pellets filtered out of the sample at the end of the trial, and hourly rates of ammonium and phosphorus excretion by taking the difference of snail treatment and the average of control (no snail) treatment concentrations. We will determine mass-specific excretion and egestion rates using a length-mass regression curve, and calculate areal rates using densities from 3 surveyed shoal reaches on Ichawaynochaway Creek. Additionally, we will calculate volumetric excretion using areal rates, reach area, and discharge from nearby USGS gauges to understand how snail excretion impacts background nutrient concentrations during different flow conditions. We expect excretion and egestion rates to vary across sites due to differences in snail density, and that excretion will contribute a larger proportion of nutrients during low-flow periods. Our results will shed light into the functional role of an endemic pleurocerid in a low-gradient, coastal plain stream, illustrating the ecological significance of an under-studied group of freshwater organisms.

Poster Authors: Georgeanna Randall², L. Caitlin Sweeney^2,1, Stephen W. Golladay^1,2, Jerry Miller³, and Jason Love⁴

Institution or Organization: ¹The Georgia Water Planning and Policy Center at Albany State University, ²The Jones Center at Ichauway, University of Alabama,  ³Department of Geosciences and Natural Resources, Western Carolina University; ⁴Highlands Biological Station

Poster Abstract:

Microplastics (MPs) are small plastic particles measuring 5 mm or less in size. There is concern about toxicological effects on biota that might ingest MPs, including humans. Awareness of MPs is recent, especially in freshwater, where sources include wastewater, nonpoint source runoff, and fragmentation of plastic debris. Urban areas are assumed as primary contributors and MP studies have overlooked rural or predominantly forested watersheds. Yet, freshwaters in rural areas are subject to MP contamination from biosolids and fertilizer amendments to farmlands. Multiple studies have detected MPs in remote areas, pointing research in the direction of exploring different pathways for MP transport. Herein we summarize MP surveys from 2 southeastern watersheds of contrasting size, geology, and land use. MPs in small headwater basins in the Southern Blue Ridge Mountains have been monitored since 2021 in a joint effort between Western Carolina University and Highlands Biological Station. This study area was unique in that a mature forest with limited human access was represented and can be considered a reference site.  Atmospheric deposition of MPs was identified as a major pathway for stream contamination with an atmospheric deposition rate of ~125 MPs/m^2/Day. In 2021, MP pollution in an agriculturally dominated watershed of the Gulf Coastal Plain was conducted. Agriculture has consolidated in the uplands and the combination of karst geology and intact riparian corridors buffer streams from runoff. MP concentrations were positively correlated with soluble reactive phosphorus (SRP), being greatest downstream from wastewater treatment plants. Consistent, detectable microplastic concentrations were observed in reaches without wastewater discharge and with intact riparian zones. Potential sources were not assayed but included atmospheric deposition. We found that microplastic contamination of freshwater is not strictly an urban problem. We detected significant microplastic contamination in two rural watersheds with contrasting land use. We encourage studies of microplastic origin in areas with low population density. While absolute concentrations of MPs may be lower, the large amount of rural land in the southeastern US may represent a large source of MP to downstream and nearshore marine environments.