SFS Annual Meeting

6/03/2024  |   13:30 - 13:45   |  Independence Ballroom B

Dam legacies affect riparian structure and functions at multiple ecosystem levels along the riverine continuum Dams and their legacies have significantly impacted waterways and river corridors worldwide. While much of the previous research has focused on effects of dams and their legacies on the longitudinal exchange and transport of water, sediment, and nutrients through the stream network much less attention has been paid on their effects on riparian ecosystems. Here we show that dams can alter the structure, processes, and function of riparian systems and the lateral and vertical exchange of water and nutrients between the stream and the riparian zone. We propose that these legacy effects cascade through multiple ecosystem levels altering riparian topography and sediment characteristics, hydrologic exchange, redox environment, biogeochemical processes and microbial structure and functions. These effects differ upstream and downstream of the dams and can persist for variable time periods across ecosystem levels. Where relict dams still exist, riparian zones can be persistently saturated and hypoxic/anoxic with important consequences for nutrient cycling and processing. Where dams have been removed or breached, riparian systems may be perched and hydrologically disconnected from the stream network. Contrasting redox environments may especially affect the cycling and coupled transformations of redox sensitive elements like nitrogen, iron, and organic carbon. We highlight these effects using examples of widespread milldams and their legacies in the mid-Atlantic US and other dams across the world. Understanding how the “memories” and effects of anthropogenic legacies vary and persist through river corridors and how they affect contemporary and future processes and functions is important for better management of these ecosystems.

Shreeram Inamdar (Primary Presenter/Author), University of Delaware, inamdar@udel.edu;

Marc Peipoch (Co-Presenter/Co-Author), Stroud Water Research Center, mpeipoch@stroudcenter.org;

Jinjun Kan (Co-Presenter/Co-Author), Stroud Water Research Center, jkan@stroudcenter.org;

Md Moklesur RAHMAN (Co-Presenter/Co-Author), University of Delaware, mmrahman@udel.edu;

Matthew Sena (Co-Presenter/Co-Author), University of Delaware, senam@udel.edu;

Bisesh Joshi (Co-Presenter/Co-Author), University of Delaware, bjoshi@udel.edu;

Joseph Galella (Co-Presenter/Co-Author), University of Delaware, jgalella@udel.edu;

Alexis Yaculak (Co-Presenter/Co-Author), University of Delaware, yaculak@udel.edu;

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6/03/2024  |   13:45 - 14:00   |  Independence Ballroom B

Going with the flow: the supply and demand of sediment retention ecosystem services for the reservoirs in Puerto Rico Safeguarding the longevity of reservoirs by preventing sedimentation is of clear public interest, but few consumers are aware of the natural features that provide sediment retention services and the economic importance of their conservation. Moreover, managing for landscape level sediment retention services is challenging due to a lack of clarity regarding supply and demand flows that transcend watershed boundaries and jurisdictions. Our study seeks to bridge these gaps by characterizing the flow of sediment retention services to reservoirs and link these services to the specific consumers that benefit using a socio-ecological network (SEN) framing. We conducted this study in Puerto Rico (PR), the population of which is heavily reliant on reservoirs as a primary water resource, while experiencing chronic reservoir sedimentation problems. We modelled avoided sediment export, and the costs averted thanks to this service. We characterized vulnerability of these sediment retention services by estimating their legal conservation status and their fragmentation. We frame these services as a SEN by using water distribution lines as links to estimate the number of beneficiaries and their location relative to the reservoir’s water source. Our results identify where to prioritize conservation efforts to safeguard access to clean water in PR. Our study also provides a case study for establishing supply and demand service flows of water purification services in order to justify conservation policies based on ecosystem services.

Rebeca de Jesus Crespo (Primary Presenter/Author), Louisiana State University, rdejesuscrespo1@lsu.edu;

Mariam Valladares-Castellanos (Co-Presenter/Co-Author), Louisiana State University, mvalla3@lsu.edu;

Volodymyr Mihunov (Co-Presenter/Co-Author), Tarleton State University, vmihunov@tarleton.edu;

Thomas Douthat (Co-Presenter/Co-Author), Louisiana State University, tdouthat1@lsu.edu;

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6/03/2024  |   14:00 - 14:15   |  Independence Ballroom B

From (Corn)belt to border: Assessing changes in nitrate export patterns from westward corn-soy expansion into the Great Plains The westward expansion of intensive row crop agriculture, such as corn-soybean cultivation, outside of the ‘Cornbelt’ region and into the Great Plains has accelerated in recent decades. This expansion raises concerns for local to regional water quality, especially considering the water quality degradation and legacy N accumulation of the Cornbelt. Moreover, Great Plains landscapes are inherently different from previously N saturated regions (e.g., in climate, geology, vegetation) so the consequences of this expansion on water quality and legacy storage mechanisms are uncertain. To shed light on this uncertainty, we leveraged publicly available datasets to investigate the impact of the westward expansion of corn-soy on regional nitrate concentration-discharge (CQ) behavior. Specifically, CQ slopes were calculated for 20 midwestern watersheds that have experienced various rates of corn-soy cultivation. This was done for two time periods (pre and post 2007), to assess the effects of corn-soy incentivizing policy on nitrate concentrations, and for various flow conditions (‘high’ and ‘low’), as CQ relationships can be non-linear. Preliminary results show that the response in CQ slopes from pre to post 2007 varies across the region and with flow conditions. Specifically, CQ slopes for Great Plains watersheds have shifted up (more enriching) at low flows and down (more diluting) at high flows, while the inverse is true for Cornbelt watersheds. This study illuminates region-specific nitrate responses to land use changes that can guide local to regional water quality management to foster sustainable agricultural practices in this evolving landscape.

Bre Rivera Waterman (Primary Presenter/Author), University of Kansas, bre.waterman@ku.edu;

Amy Hansen (Co-Presenter/Co-Author), University of Kansas, amy.hansen@ku.edu;

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

Matthew Kirk (Co-Presenter/Co-Author), Kansas State University, mfkirk@ksu.edu;

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6/03/2024  |   14:15 - 14:30   |  Independence Ballroom B

Small but Mighty: Utilization of Macroinvertebrates as Indicator Species of Stream Health Across Different Land Use Areas in Vermont Anthropogenic activities, including land use changes, have a significant impact on the physical and chemical characteristics of streams. Urban streams are particularly vulnerable to alterations in nutrient loads, hydrological regimes, and physicochemical variables, which can lead to reduced biodiversity and negative impacts on ecosystem processes. In this study, I will assess the water quality in two local Vermont streams (one in an urban area, and one in a forested area) based on their respective macroinvertebrate species richness, abundance, and functional traits. The results of this study will help inform us of the response of aquatic organisms to changes in land use. It is imperative to understand the effect of land use on local macroinvertebrates and stream health, so that we may be more aware of human’s effect on natural streams and how to avoid stream health degradation. My research specifically, will have implications for natural water source legislature and management in Vermont.

Maya Thomson (Primary Presenter/Author), University of Vermont , maya.thomson@uvm.edu;

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6/03/2024  |   14:30 - 14:45   |  Independence Ballroom B

DOES ORGANIC AGRICULTURE IMPROVE WATER QUALITY? Non-point source pollution from farms is a major concern for freshwater ecosystems within and downstream from agricultural landscapes. Growers use multiple practices to achieve food production goals and these practices can differentially influence pollution. Despite the growing popularity of organic agriculture, researchers have conducted few experiments directly comparing the water quality consequences of conventional and organic agriculture. Here we present a literature review of the consequences for surface water quality from paired studies of conventionally and organically grown row crops. From a total of 5,851 initial titles, 37 peer-reviewed papers met our criteria for inclusion in the review. We extracted measured chemical and physical values including herbicides, phosphorus, nitrogen, total runoff, and total suspended solids. Agricultural management, combined with crop choice and soil characteristics, uniquely influenced each water quality parameter. Preliminary analysis suggests that for most parameters, pollutant loads decreased with organic agriculture. In 79% of paired study comparisons, nitrate leaching in the organic paired field resulted in a negative percent change for nitrate loads relative to conventional fields. Total phosphorus losses through runoff were more frequently lower in organic fields, but the percentage change of losses through leaching were more often higher in organically farmed fields. Collectively, the scarcity of paired field studies limits our understanding of how transitions from conventional to organic agriculture generally influence water quality parameters. Our review also highlights the importance of accounting for additional techniques such as no-till or cover crops to parse the mechanisms behind these varied water quality responses.

Raven Bier (Primary Presenter/Author), University of Georgia, rbier@srel.uga.edu;

Melinda Daniels (Co-Presenter/Co-Author), Stroud Water Research Center, mdaniels@stroudcenter.org;

Diana Oviedo-Vargas (Co-Presenter/Co-Author), Stroud Water Research Center, doviedo@stroudcenter.org;

Marc Peipoch (Co-Presenter/Co-Author), Stroud Water Research Center, mpeipoch@stroudcenter.org;

Jinjun Kan (Co-Presenter/Co-Author), Stroud Water Research Center, jkan@stroudcenter.org;

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6/03/2024  |   14:45 - 15:00   |  Independence Ballroom B

ECOTOXICITY OF A NOVEL SPENT COFFEE GROUND BIOSORBENT DESIGNED FOR NITRATE REMEDIATION. Quaternized spent coffee grounds (QCG) were designed as a low-cost biosorbent to remove nitrates from small streams. Previously presented work showed that over 90% nitrate adsorption occurred in 24 h in spiked (25 mg/L) stream waters at field-relevant parameters. To increase the environmental relevance, a simplified microcosm study was conducted using field-collected water and sediment. In spiked stream samples, sediments alone, QCG alone and sediments+QCG removed 35.1%, 52.0% and 86.2% of nitrates, respectively. The unexpected presence of snails in the sediment allowed for an initial toxicity assessment; no snails remained visible at 72 h in any of the QCG treatments. A significant increase in conductivity in all QCG treatments (control: 229.9 ?S/cm initially to 1143.7 ?S/cm at 72 h) suggested that leaching from the biosorbent was potentially harmful. To formally investigate toxicity, QCG leachate was used in ecotoxicity studies on microalgae Pseudokirchneriella subcapitata (Algaltoxkit F™) and Daphnia magna (Daphtoxkit F™). QCG leachate inhibited algae growth at 72 h at all concentrations tested (4-40 g/L) likely due to a significant decrease in light availability. Studies on daphnia showed 100% immobilization at 48 h (4 g/L), due to particulate matter in the leachate coating organisms. Centrifugation of the leachate improved the accumulation of residues qualitatively but still caused 100% immobilization. Concentrations of 4 and 40 mg/L did not cause any adverse effect on D. magna. Thus, QCG shows great potential for nitrate removal, but its design requires improvement to reduce leachate and rigorous testing to ensure that it is safe to the ecosystem.

Nayla Rhein (Primary Presenter/Author), University of Otago, nayla.rhein@gmail.com;

Rhonda J. Rosengren (Co-Presenter/Co-Author), University of Otago, rhonda.rosengren@otago.ac;

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