SFS Annual Meeting

Todd Osborne (Co-Presenter/Co-Author)
University of Florida, osbornet@ufl.edu;

Anna Thornton (Co-Presenter/Co-Author)
Whitney Laboratory for Marine Bioscience - University of Florida, anna_t@whitney.ufl.edu;

Tracey Schafer (Co-Presenter/Co-Author)
Whitney Laboratory for Marine Bioscience - University of Florida, tschafer25@gmail.com;

Paul Jones (Co-Presenter/Co-Author)
South Florida Water Management District, pajones@sfwmd.gov;

Paul Julian (Primary Presenter/Author)
Whitney Laboratory for Marine Bioscience - University of Florida, pjulian@ufl.edu;

Abstract: Lake Okeechobee provides essential ecosystem services that are threatened by current and historic excessive inputs of phosphorus (P), influencing endo- and exogenic processes leading to fish-kills, hypoxic events, algal blooms, and degraded aquatic habitat. Over the last decade and a half, nutrient loading to the lake has significantly increased. Utilizing the long-term ambient monitoring network, this study evaluated water column total nitrogen (TN), total P (TP), and chlorophyll-a (Chl-a)and identified significantly declining trends in TN and Chl-a, and increasing trends in TP. Additionally, over the last 30 years, data from four spatially explicit lake sediment surveys indicate sediment N and P concentrations vary spatially and temporally. The nutrient balance of Lake Okeechobee and the understanding of endo and exogenic drivers of nutrient mobilization are important to aid in the restoration of the Lake and the Greater Everglades. As restoration activities progress, it is expected that nutrient inputs to the lake will decline. However, given the volume of N and P stored in the lake's sediments, internal loading could result in delayed improvements to nutrient concentrations within the Lake.

Yvonne Vadeboncoeur (Primary Presenter/Author)
Wright State University, yvonne.vadeboncoeur@wright.edu;

Simon Stewart (Co-Presenter/Co-Author)
Cawthron Institute, simon.stewart@cawthron.org.nz;

Marianne Moore (Co-Presenter/Co-Author)
Wellesley College, mmoore@wellesley.edu;

Sudeep Chandra (Co-Presenter/Co-Author)
Global Water Center and Biology Department, University of Nevada, Reno, sudeep@unr.edu;

Abstract: Littoral zones of clear lakes with excellent water quality are experiencing prolonged greening events. Throughout the world, nearshore, well-lit habitats are increasingly carpeted by luxuriant growths of attached filamentous algae. Are littoral filamentous algal blooms (FABs) an early indicator of eutrophication in lakes that are newly exposed to anthropogenic nutrient loading? Or are FABs an emerging threat to clear lakes generated by the combined effects of groundwater pollution, weakened top-down control, and climate-induced changes in hydrodynamics? We review conceptual models developed at a 2019 international workshop on FABs. FABs require high light intensities and proliferate in clear lakes where nutrient concentrations in ground water is high relative to the overlying water. Filamentous chlorophytes may have high nitrogen demand, and overtake other benthic taxa when N:P is high and grazing is weak. As climate changes, longer growing seasons and stronger stratification may keep water columns clear. Climate-driven changes in terrestrial landscapes may be accelerating groundwater nutrient loading, facilitating the development of FABs. Current limnological models and monitoring practices leave us ill-equipped to advise the public on management and prevention of this emerging threat to clear lakes.

Shuyu Chang (Primary Presenter/Author)
University of Illinois at Chicago, schang68@uic.edu;

Qian Zhang (Co-Presenter/Co-Author)
University of Maryland Center of Environmental Science/ Chesapeake Bay Program, qzhang@chesapeakebay.net;

Danyka Byrnes (Co-Presenter/Co-Author)
University of Waterloo, danyka.byrnes@uwaterloo.ca;

Nandita Basu (Co-Presenter/Co-Author)
University of Waterloo, nandita.basu@uwaterloo.ca;

Kimberly Van Meter (Co-Presenter/Co-Author)
University of Illinois at Chicago, kvanmete@uic.edu;

Abstract: In the Chesapeake Bay, excess N has for decades fueled algal growth, disrupted aquatic ecosystems, and negatively impacted coastal economies. Despite widespread implementation of measures and notable reductions in N inputs since 1980, water quality across the region has been slow to improve, which has in some cases been attributed to an accumulation of surplus N in subsurface reservoirs. Here, we use the ELEMeNT-N modeling framework to explore the role of legacy N in slowing reductions in N loading to the Bay, and to provide estimates of the time required to meet water quality goals in nine major tributary watersheds. Our results first show that recent improvements in water quality can be attributed to decreases in N surplus that began to occur in the 1970s and 1980s. Future simulations suggest that, even with no additional changes in current management practices, goals to reduce N loads by 25% can nearly be met within the next two decades. The present results also suggest that time lags to achieving water quality may vary considerably in the individual study watersheds, with the longest lag times being found in the highly agricultural Choptank watershed.

Eric Moore (Primary Presenter/Author)
University of Connecticut, eric.m.moore@uconn.edu;

Janet Barclay (Co-Presenter/Co-Author)
USGS New England Water Science Center, Hartford, jbarclay@usgs.gov ;

Kevin Jackson (Co-Presenter/Co-Author)
University of Connecticut, kevin.jackson@uconn.edu ;

Adam Haynes (Co-Presenter/Co-Author)
University of Connecticut, adam.haynes@uconn.edu;

Martin Briggs (Co-Presenter/Co-Author)
U. S. Geological Survey, Hydrogeophysics Branch, Storrs, Connecticut, USA, mbriggs@usgs.gov;

Ashley Helton (Co-Presenter/Co-Author)
University of Connecticut, ashley.helton@uconn.edu;

Abstract: Groundwater throughout the United States is saturated with excess nutrients infiltrating from overlying land cover. We used handheld thermal infrared cameras to extensively characterize locations of groundwater seeps (n > 300) throughout the Farmington River watershed. Groundwater was sampled from over 170 identified groundwater seeps for major anions, total nitrogen, denitrification, and greenhouse gases to understand spatial heterogeneity in the biogeochemistry of groundwater seeps and its relationship to surrounding watershed characteristics. We observed extensive spatial heterogeneity in groundwater biogeochemistry with some nitrate concentrations differing by 2 orders of magnitude at adjacent groundwater seeps within 10 m. We combined our spatially distributed biogeochemical data with a MODPATH groundwater particle-tracking model and historical landcover to connect groundwater residence times and flowpaths to source area landcover. We found that source area (r = -0.35, p <.05) and local buffer (r= -0.45, p<.05) percent forested landcover were associated with lower total nitrogen concentrations highlighting the role of riparian vegetation in reducing legacy nutrient loading from groundwaters to surface waters. Preliminary data suggests the broader range of inputs from source area landcover contributes to the spatial heterogeneity in groundwater seep biogeochemistry.

Emma Rosi (Co-Presenter/Co-Author)
Cary Institute of Ecosystem Studies, rosie@caryinstitute.org;

Arial Shogren (Co-Presenter/Co-Author)
University of Alabama, ashogren@ua.edu;

Jennifer Tank (Co-Presenter/Co-Author)
University of Notre Dame, jtank@nd.edu;

David Fischer (Co-Presenter/Co-Author)
Cary Institute, fischerd@caryinstitute.org;

Scott Egan (Co-Presenter/Co-Author)
scott.p.egan@rice.edu , Rice University;

Pedro Brandao Dias F Pinto (Primary Presenter/Author)
Rice University, pb21@rice.edu;

Abstract: Environmental proteins (eProteins), such as Cry-proteins associated with genetically-engineered (GE) organisms, are present in ecosystems worldwide, but only rarely reach concentrations with detectable ecosystem-level impacts. Despite their ubiquity, the degradation and fate of Cry and other eProteins are mostly unknown. Here we report the results of an experiment where we added Cry-proteins leached from GE Bt maize to a suite of 19 recirculating experimental streams. We found that Cry exhibited a biphasic degradation with an initial phase of rapid and variable degradation within one hour, followed by a slow and steady phase of degradation with traces of protein persisting after 48 hours. The initial degradation was correlated with heterotrophic respiration and water column dissolved oxygen, confirming an association with stream metabolism. However, protein degradation persisted even with no biofilm, and was faster at more acidic pH, suggesting that water chemistry is also critical in both degradation and subsequent detection. We suggest that Cry, as well as other eProteins, will have a rapid degradation caused by denaturation of proteins and pH changes, which confirms that the detection of Cry-proteins in natural streams must be the result of steady and consistent leaching.

Hannah Whaley (Primary Presenter/Author)
Missouri State University, hlw97@live.missouristate.edu;

La Toya Kissoon-Charles (Co-Presenter/Co-Author)
Missouri State University , LKissoon@Missouristate.edu;

Abstract: In the Ozarks region of Missouri and Arkansas, there are numerous springs that are commonly impounded to create ponds for agricultural and recreational use. Spring-fed ponds are often susceptible to eutrophication, which can have large impacts on their aquatic plant communities. High nutrient levels (nitrogen and phosphorous) can lead to high turbidity, low submerged plant abundance, and high abundance of nuisance vegetation. These problems lend themselves to difficulties in recreational activities, a decrease in the natural aesthetic, and greatly decrease water quality. Although rural and urban ponds have different sources of pollution, both can exhibit the same symptoms of low water quality. We surveyed 11 spring-fed ponds, 6 rural and 5 urban, to compare plant communities and water quality. We expected to find higher plant diversity in rural ponds and lower diversity in ponds with higher nutrient concentrations. As expected, we found a pattern of higher species diversity in rural ponds. However, the ponds with the highest nutrient concentrations also had the highest species diversity. We suspect that other factors may be contributing to the difference in species diversity, such as physical characteristics like surface area and depth.

Kiara C. Cushway (Primary Presenter/Author)
Central Michigan University, cushw2kc@cmich.edu;

Nathan S. Ring (Co-Presenter/Co-Author)
Central Michigan University, ring1ns@cmich.edu;

Daelyn A. Woolnough (Co-Presenter/Co-Author)
Central Michigan University, wooln1d@cmich.edu;

David K. Patton (Co-Presenter/Co-Author)
Central Michigan University, patto1d@cmich.edu;

Abstract: Understanding threats that imperiled organisms like freshwater mussels face is imperative for aquatic management. Knowledge of the ways in which freshwater mussels interact and are influenced by the environment provides insight into the focus of management and conservation actions. This study examined the impacts of land use, surficial geology, and slope on native freshwater mussel (unionid) and invasive mollusk (corbiculid) abundance, as well as unionid species richness, in the Kalamazoo River, Michigan, USA using data collected in 2018 and 2019. GIS and Spearman's rank correlation analyses at multiple spatial scales indicated that relationships exist among unionid richness and abundance or corbiculid abundance and various land use and geology types within the watershed. In addition, different species of freshwater mussels exhibit varying relationships with differing land use and geology types. Our results emphasize the need to incorporate spatial information into our understanding of the relationships between organisms and their environments and contribute to existing evidence of the impacts that landscape factors can have on the abundance and distribution of both native and invasive organisms.

Janaye Hanschu (Primary Presenter/Author)
University of Kansas, janayeh@ku.edu;

Abstract: Human activities have increased the frequency and intensity of cyanobacteria harmful algal blooms (cyanoHABs). Although phosphorus contributes to cyanoHABs, emerging work suggests nitrogen also influences cyanoHABs. Yet, the effects of nitrogen form and concentration on microbiomes and toxin production remain unclear. We manipulated nitrogen in 300 L aquatic mesocosms to address: (1) What form of nitrogen (nitrate vs. ammonium) fuels cyanoHAB development? (2) How does prior bloom history from a lake affect the propensity to stimulate new blooms with added nitrogen? Five nitrogen treatments, high/low nitrate, high/low ammonium, and a no added nitrogen control, were set up in triplicate (question 1) using water from each lake type compared: mesotrophic and eutrophic (question 2). We found chlorophyll-a concentration was higher in the eutrophic relative to the mesotrophic lake, and increased more following high levels of nitrate and ammonium addition in the eutrophic waters. Microcystin was ~750x higher in the sedimentation than in the water column. The sedimentation microbiome community was different in each lake and each lake responded to nitrogen additions differently. The eutrophic lake responded to nitrogen additions more strongly.

Nicholas Kiulia (Primary Presenter/Author)
Institut National de la Recherche Scientique (INRS-ETE), Quebec, Canada, nicholas.kiulia@ete.inrs.ca;

Mariem Fadhlaoui (Co-Presenter/Co-Author)
Institut National de la Recherche Scientique (INRS-ETE), Quebec, Canada, mariem.fadhlaoui@ete.inrs.ca;

Adam Yates (Co-Presenter/Co-Author)
University of Waterloo, adam.yates@uwaterloo.ca;

Isabelle Lavoie (Co-Presenter/Co-Author)
Institut National de la Recherche Scientifique, Centre Eau Terre Environnement, isabelle.lavoie@inrs.ca;

Abstract: There has been an increase in interest for the use of biofilm fatty acids (FAs) as a proxy for basal food resource quality and as a potential stream assessment tool. However, new knowledge is needed to support use of FAs in monitoring of human impacts such as those associated with eutrophication. Biofilm samples were collected from 45 streams representing a nutrient-enrichment gradient in southern Quebec (Canada). Among all the sampling sites, saturated FA (SFA) were generally the most abundant, accounting for 30% to 56%. The major SFA detected were C16:0 and C18:0, while the major monounsaturated (MUFA) were C16:1?7 and C18:1?9. The polyunsaturated FA (PUFA) detected at high proportions were C18:2?6 [LIN], C18:3?3 [ALA], and C20:5?3 [EPA]. Ordination based analyses showed marked difference in FA composition among stations, but relationships with nutrient concentrations and diatom-based assessment indices were not clear. Indeed, contrary to our hypothesis, certain nutrient-enriched streams located in heavily farmed areas showed high proportions of essential fatty acids suggesting high nutritional quality of the biofilms. Further study is needed to understand how FA composition of stream biofilms respond to nutrients.

Cecilia Leal (Primary Presenter/Author)
University of São Paulo “Luiz de Queiroz” College of Agriculture (ESALQ/USP), c.gontijoleal@gmail.com;

Silvio Frosini de Barros Ferraz (Co-Presenter/Co-Author)
University of São Paulo, USP/ESALQ, Dept of Forest Sciences, Brazil, silvio.ferraz@usp.br;

Rafael Leitão (Co-Presenter/Co-Author)
Universidade Federal de Minas Gerais, ecorafa@gmail.com;

Leandro Juen (Co-Presenter/Co-Author)
Universidade Federal do Pará, leandrojuen@gmail.com;

Vivian Campos (Co-Presenter/Co-Author)
Instituto Nacional de Pesquisas da Amazônia, vco.vivian@gmail.com;

Janaína Brito (Co-Presenter/Co-Author)
Instituto Nacional de Pesquisas da Amazônia, janaina.gomesdebrito@gmail.com;

José Max de Oliveira-Junior (Co-Presenter/Co-Author)
Universidade Federl do Oeste do Pará, josemaxoliveira@gmail.com;

Abstract: Agricultural expansion is among the main drivers of freshwater biodiversity loss in tropical landscapes. In addition to the conversion of native vegetation for crops and livestock, agriculture activity is often accompanied by an increase in roads and associated culverts, which can disrupt the movement of water, sediment, organic matter, and species. In this study we evaluate the impacts of road stream crossings on physical habitat and biotic assemblages (fish and invertebrate) in 83 small streams (1st to 3rd Strahler order) in the eastern Brazilian Amazon. We found on average 3.4 (0-20; +3.3) road crossings within 5km buffer in each sampling site. Physical habitat changes were related to increased water temperature and fine sediment as well as modifications in channel morphology. Biotic assemblages showed mixed, but overall negative, responses to stream fragmentation. Road stream crossings are ubiquitous in human modified Amazonian landscapes, yet largely ignored. Acknowledging their pervasive occurrence and quantifying their impacts to stream connectivity and biodiversity is a necessary paradigm shift for protecting freshwater ecosystems.

Gabriella Lawson (Primary Presenter/Author,Co-Presenter/Co-Author)
Brigham Young University, gmloosle@gmail.com;

Abstract: Excess nutrients from anthropogenic sources may escalate harmful algal and cyanobacteria blooms (HABs) even as lakes continue to become more eutrophic. To evaluate the extent that specific nutrient additions influence cyanobacterial species, phytoplankton and cyanotoxin production in hypereutrophic waters, we imposed three nutrient additions (i.e., N, P and N+P) and a control in in-situ bioassays over multiple seasons in a large shallow hypereutrophic lake (Utah Lake, UT, in the USA). We found that hypereutrophic waters elevated the cyanobacterial pigment, phycocyanin to bloom status regardless of the nutrient treatment and location across the lake, in summer, late summer, and fall. P-additions intensified phycocyanin concentrations more than any other treatment even under hypereutrophic conditions. For phytoplankton, hypereutrophic conditions initiated or boosted HABs across all seasons, locations, and treatments, and production was co-limited by N and P. Microcystin, cylindrospermopsin, and anatoxin-a concentrations demonstrated seasonal signals that were not necessarily related to the severity of the cyanobacterial blooms but were primarily associated with the alleviation of N-limitations. Our results demonstrate that the addition of specific nutrients intensify components of HABs and stimulate cyanotoxin production even under hypereutrophic conditions.

Erin Brooks (Co-Presenter/Co-Author)
University of Idaho, ebrooks@uidaho.edu;

Sarah Roley (Co-Presenter/Co-Author)
Washington State University, sarah.roley@wsu.edu ;

David Huggins (Co-Presenter/Co-Author)
Washington State University, dhuggins@wsu.edu;

Aline Ortega Pieck (Primary Presenter/Author)
University of Idaho, alineorteg@gmail.com;

Abstract: Nitrate export from artificially-drained agricultural watersheds deteriorates water quality and impairs ecosystem function. Stream processes, such as whole-stream metabolism (gross primary production and ecosystem respiration), provide regulating ecosystem services that can lower nitrate export. Yet the capacity of streams to significantly decrease nitrate loadings is inherently tied to land management practices and climate characteristics. In this study we used a high-frequency sampling approach (15 min – 1 h) to assess the timing and magnitude of nitrogen export and stream metabolic rates throughout a water year in a semi-arid, temperate, agricultural stream in the Inland Northwest USA. We hypothesized that peak watershed export and stream metabolism would occur asynchronously causing the latter to have a small relative influence on the annual nitrate loading. Our results show that most of the nitrate travels downstream during the winter and spring seasons when stream metabolism is at its lowest. These findings highlight the importance of land use and climate to contextualize stream ecosystem services. Implementing land management practices that reduce nitrate concentration before water reaches the stream is imperative to improve regional water quality.

Chelsea Clifford (Primary Presenter/Author)
Iowa State University, chelseaclifford@gmail.com;

Matthew Helmers (Co-Presenter/Co-Author)
Iowa State University, mhelmers@iastate.edu;

Abstract: Agricultural streams face many of the same stressors as urban streams, but lack the best recognized driver of “urban stream syndrome,” increased flashiness due to impervious surfaces quickly diverting precipitation to streams. However, industrialized row-cropping in temperate climates has its own massive network of pipes diverting water, hidden approximately 1m below soil, in the form of tile drainage. This study seeks to parse the effects of tile drainage on hydrology and nutrient excesses through structural equations modeling of the 28 sites in the USGS’s and USEPA’s 2013 Midwest Stream Quality Assessment co-located with National Water Information System automated stream gauges, allowing calculation of the Richards-Baker Flashiness Index paired with physical, chemical, and biological data. Results demonstrate that in the Midwest, while crop-heavy watersheds have less flashy streams than watersheds with more impervious and urban land uses, among cropped watersheds, tile-drained areas yield greater flashiness than non-tile-drained row crops. Stream nitrate concentration also increased significantly with tile drainage. In future attempts to understand and improve these entangled problems of flashiness and nitrate export from tile drainage, we may be able to learn from practices already attempted in urban settings.

Jon Hathaway (Co-Presenter/Co-Author)
University of Tennessee, hathaway@utk.edu;

Ania Szynkiewicz (Co-Presenter/Co-Author)
University of Tennessee, aszynkie@utk.edu;

Victoria Rexhausen (Primary Presenter/Author)
University of Tennessee, vrexhaus@vols.utk.edu;

Abstract: Determining the source of stormwater runoff (and thus the associated source of pollutants), is a critical need in urban hydrology to optimize siting of stormwater controls and improve water quality monitoring. This study employs stable isotope analysis to attempt to identify environmental tracers for stormwater partitioning. Three monitoring sites on a unique urban watershed with forested headwaters in the city of Knoxville, TN allowed collection of flow-paced stream samples during the course of various storm events in all four seasons. Water samples were also collected throughout the watershed during dry weather to evaluate a baseflow control. This study builds upon known isotopic environmental tracers by investigating the application of this technique to urban runoff endmembers, such as roadway, rooftop, and grass runoff sources. The results are essential to understanding impervious surface connectivity and how that effects nutrient sources and transport during storm events.

Talia Pope (Primary Presenter/Author,Co-Presenter/Co-Author)
Kent State University, tpope8@kent.edu;

Lauren Kinsman-Costello (Co-Presenter/Co-Author)
Kent State University, lkinsman@kent.edu;

Anne Jefferson (Co-Presenter/Co-Author)
Kent State University, ajeffer9@kent.edu;

Laura Sugano (Co-Presenter/Co-Author)
Kent State University, lsugano@kent.edu;

Marie Stofan (Co-Presenter/Co-Author)
Kent State University, mstofan1@kent.edu;

Hayley Buzulencia (Co-Presenter/Co-Author)
Kent State University, hbuzulen@kent.edu;

Abstract: Green roofs are an effective solution for mitigating stormwater in concrete-heavy urban areas because of their ability to retain water. However, green roofs are sources of nutrients, especially phosphorus. We investigated how a green roof changes phosphate concentrations. On the roof, rainwater was sampled from a collection bucket and runoff was sampled from the downspout when there was a flow or from the collection pool if the flow had stopped. Phosphate concentrations were measured by ion chromatography. There was virtually no phosphate detected in the sampled rainwater (2 out of 53 samples were below the detection limit of 0.01ppm, concentrations ranged from 0.004 to 0.087 ppm). Phosphate concentrations were much higher in runoff (mean 2.132ppm +/- 1.385ppm, N=99). However, over 3 years there appeared to be an overall decrease in phosphate concentrations in response to altered maintenance. The studied green roof is a commonly used product and suggests that green roofs are often a net source of P. Future research should evaluate the water quality impacts of green roofs along with hydrologic and other ecosystem services.

Kari Snelding (Primary Presenter/Author)
University of Kansas, ksnelding4@gmail.com;

Kynser Wahwahsuck (Co-Presenter/Co-Author)
University of Kansas, kwahwah11@gmail.com;

Amy Burgin (Co-Presenter/Co-Author)
University of Kansas, burginam@ku.edu;

Abstract: Synthesis of daily metabolism measurements from different streams and rivers have revealed a great deal of temporal variation in gross primary production (GPP) and ecosystem respiration (ER). However, attempts to relate variation in GPP and ER to land use remains limited. Land use may be an important control on ecosystem metabolism because nutrients often limit the amount of biological activity in ecosystems. Thus, we ask: How does land use and associated differences in nutrient inputs affect stream metabolism? We examine the effect of land use using high-frequency sensors placed in six streams. Three streams draining predominantly grassland (>80%) and three streams draining cropland (>80%) watersheds. Sensors were installed in March and removed in December, allowing us to examine annual seasonal dynamics in addition to land use effects. We predict that in cropland draining watersheds there will be higher GPP and ER than grassland watersheds. Understanding the connections between land use and stream metabolism may help us better manage aquatic resources.

David Manning (Co-Presenter/Co-Author)
University of Nebraska at Omaha, davidmanning@unomaha.edu;

Andrew Miller (Co-Presenter/Co-Author)
University of Nebraska at Omaha, andrewmiller@unomaha.edu;

Jessica Rodino (Primary Presenter/Author)
University of Nebraska at Omaha, jessrodino@gmail.com;

Abstract: Prairie streams in the Great Plains drain watersheds with mosaics of land use, but the impact of such spatially heterogeneous riparian vegetation on nearby streams remains underexplored. Glacier Creek, Nebraska, USA, drains two sub-watersheds with agriculture and restored prairie, where a previous study indicated higher rates of primary production even in low-light conditions within the agricultural sub-watershed, vs. higher heterotrophic respiration near the restored prairie. Here, we examined spatial heterogeneity of nitrogen (N) vs. phosphorus (P) limitation of benthic algae using nutrient diffusing substrata (NDS) placed within 3 50-m reaches of Glacier Creek with differing proximate land use: restored prairie, agriculture, and downstream of the confluence of these two reaches. Autotrophs were inhibited by N (ln-response ratio [lnRR] = -0.76] and P (lnRR = -0.15) in the agricultural reach, despite having lower average streamwater nutrient concentrations in this reach. Conversely, restored prairie and confluence reaches showed stronger P-limitation (lnRR = 0.37, 0.57) when compared to N (lnRR = -0.04, 0.44). These results provide important context to how nearby agricultural vs. restored prairie land use affects patterns of algal nutrient limitation in small grassland streams, particularly those that contain prairie restoration.

Kelly Maloney (Co-Presenter/Co-Author)
U.S. Geological Survey, kmaloney@usgs.gov;

Gregory Noe (Co-Presenter/Co-Author)
U.S. Geological Survey, gnoe@usgs.gov;

Sally Entrekin (Co-Presenter/Co-Author)
Virginia Tech, sallye@vt.edu;

Abigail Belvin (Primary Presenter/Author)
Virginia Polytechnic Institute and State University , abigail.belvin@gmail.com;

Dylan Spedaliere (Co-Presenter/Co-Author)
Virginia polytechnic Institute and State University , dylans00@vt.edu;

Abstract: The Chesapeake Bay is one of the largest estuaries in the world, sustaining the economies of hundreds of communities and providing habitat for more than 3000 migratory and residential species, yet degraded by sediment and nutrients in the upper watershed. As stakeholders restore Chesapeake streams, programs focused on mitigating the effects of anthropogenic threats, like agriculture, suffer knowledge gaps about how abiotic alterations influence macroinvertebrate biotic responses. To better understand these relationships, we compiled and summarized 41 research papers of best management practices (BMPs) that aim to mitigate alterations affecting macroinvertebrate assemblages. We predicted these studies would show that, in general, BMPs would ameliorate alterations, resulting in positive macroinvertebrate responses across different land uses. The most common BMPs (55%) focused on restoring riparian areas. Sediment (39%) and nutrients (24%) were the most common alterations targeted for improvement, and richness was the most common positive macroinvertebrate response (22%). Despite 331 documented macroinvertebrate structural responses to BMPs across 41 papers, 102 focused on functional proxies, and only 2 examined function. We will use these larger trends to guide future research on macroinvertebrate functional responses to BMPs in Chesapeake Bay headwater streams.

Bri Richards (Co-Presenter/Co-Author)
The University of Kansas , bri.richards@ku.edu;

Kari Snelding (Co-Presenter/Co-Author)
University of Kansas, ksnelding4@gmail.com;

Kynser Wahwahsuck (Co-Presenter/Co-Author)
University of Kansas, kwahwah11@gmail.com;

Terrance Loecke (Co-Presenter/Co-Author)
University of Kansas, loecke.terry@ku.edu;

Amy Burgin (Co-Presenter/Co-Author)
University of Kansas, burginam@ku.edu;

Kaci Zarek (Primary Presenter/Author)
University of Alabama, kacizarek10@gmail.com;

Abstract: Increased land use changes alter the chemical composition of dissolved organic matter (DOM), resulting in implications for the microbial community and ramifications for water quality. Yet, the effects of land use changes in streams, particularly agriculturally-dominated landscapes, are understudied. Therefore, we studied the effects of land use change on the composition of DOM in the six sites: three streams draining predominantly cropland watersheds (>80% row crop) and three streams draining predominantly grassland watersheds (>80% grassland). We asked: are there different DOM composition signatures in streams draining cropland versus grassland watersheds? We used fluorescence spectroscopy (freshness index (BIX) and fluorescence index (FI)) to examine how the origin of organic matter (OM) and the microbial influence vary between our two land uses. BIX and FI were comparable in biofilm and stream sediment leachate from the grassland and cropland watersheds, indicating no land use effects on DOM composition. However, we found that the OM composition varied by biomass type of the dominant vegetation in the watershed. Future work analyzing dissolved organic carbon samples to calculate the specific ultraviolet absorbance spectrum will promote further understanding of the relationship between DOM and land use effects.

Olivia Echols (Primary Presenter/Author)
Lyon College, olivia.echols@lyon.edu;

Allison Mundy (Co-Presenter/Co-Author)
Lyon College, allison.mundy@lyon.edu;

Erik Pollock (Co-Presenter/Co-Author)
University of Arkansas, epolloc@uark.edu;

Maryline Bossus (Co-Presenter/Co-Author)
Lyon College, maryline.bossus@lyon.edu;

Allyn Dodd (Co-Presenter/Co-Author)
Lyon College, allyn.dodd@lyon.edu;

Abstract: Poultry and livestock agriculture continue to expand in Northeast Arkansas, increasing the potential for nutrient enrichment and ecological degradation in critical waterways in the Mississippi Alluvial Plain. We sampled twelve tributaries of the Eleven Point and Black rivers from June 2019 to February 2020 to determine if relationships exist between poultry and livestock agriculture metrics and water quality, periphyton abundance, and invertebrate community structure and physiology. We found no significant relationships between animal agriculture and stream nutrient levels averaged over the study, though we observed a positive relationship between poultry house density and phosphorus concentrations (R2= 0.84, p= 0.001) during summer. Additionally, fewer pollution-intolerant macroinvertebrate taxa were found in tributaries closer to poultry farm operations (R2= 0.65, p= 0.03). Our findings suggest that streams near poultry farming operations need targeted mitigation to prevent further declines in sensitive invertebrate taxa. These efforts to determine the impact of animal agriculture are critical as poultry operations continue to expand in Arkansas, potentially impacting water quality and biological condition throughout the Mississippi Alluvial Plain.

Rebecca Abler (Primary Presenter/Author,Co-Presenter/Co-Author)
University of Wisconsin-Green Bay, Manitowoc Campus, ablerr@uwgb.edu;

Richard Hein (Co-Presenter/Co-Author)
University of Wisconsin-Green Bay, Manitowoc Campus, heinr@uwgb.edu;

Abstract: Tributaries of the Great Lakes cover extensive and varied landscapes including forests, agricultural lands, cities, and suburbs. This land use diversity creates the need for intensive investigations of water quality in localized tributaries in order to develop best management practices. Manitowoc County, WI, is an agriculturally dominated region where stream phosphorus loading impairs water quality, impacting ecological function, recreation, and property values. Weekly analysis of total and dissolved phosphate along the entire length of Centerville Creek showed that levels were consistently and notably above DNR thresholds. Samples collected within 24 hours of rainfall demonstrated runoff-based phosphate spikes at some, but not all, sample locations. High phosphate levels during periods of no rainfall suggest a consistent in-stream or subsurface phosphate contributions. Typically, phosphate loading in regional watersheds has been the result of surface runoff; however, our data suggest a more complex picture of phosphate sources and transport. Our data, visual stream assessment, and discussions with local agricultural professionals leads us to hypothesize that subsurface drainage, including tile drainage lines from agricultural fields, significantly contributes to nutrient loading. The data presented reinforce the need to carefully analyze localized tributary impacts.