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SFS Annual Meeting

2021 Detailed Schedule

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A BLESSING AND A CURSE? STORMWATER PONDS PROVIDE MULTIPLE POSITIVE AND NEGATIVE EFFECTS IN URBAN WATERSHEDS [Oral Presentation]

Alexander Reisinger (Primary Presenter/Author)
University of Florida, reisingera@ufl.edu;

James Sinclair (Co-Presenter/Co-Author)
Ohio State University, sinclair.130@osu.edu;

Carrie Adams (Co-Presenter/Co-Author)
University of Florida, rein0050@ufl.edu;

Eban Bean (Co-Presenter/Co-Author)
University of Florida, ezbean@ufl.edu;

Basil Iannone (Co-Presenter/Co-Author)
University of Florida, biannone@ufl.edu;

Lindsey Reisinger (Co-Presenter/Co-Author)
University of Florida, lreisinger1@ufl.edu;

Ashley Smyth (Co-Presenter/Co-Author)
University of Florida, ashley.smyth@ufl.edu;

Steven Hohman (Co-Presenter/Co-Author)
University of Florida, hohmans@ufl.edu;

Audrey Goeckner (Co-Presenter/Co-Author)
University of Florida, agoeckner@ufl.edu;

Abstract: Stormwater wet ponds (SWPs) are a common strategy implemented worldwide intended to minimize the hydrological and ecological impacts of urbanization that drive the urban stream syndrome. Although SWPs are typically designed primarily for flood control, these engineered aquatic ecosystems represent key junctions between the built and natural environments. There are at least 76,000 SWPs in Florida alone, covering nearly as much space as urban industrial or recreational areas. Here we present ongoing research focused on the duality of SWPs: the positive and negative effects these real aquatic ecosystems have in urban watersheds. Specifically, SWPs represent key habitat for aquatic and semi-aquatic plants and animals but can also harbor invasive species. Denitrification within SWPs can rapidly respond to nutrient pollution events but ponds are also often sources of nitrogen to downstream ecosystems via nitrogen fixation in sediments. SWPs can be aesthetic amenities for the surrounding community, but aesthetic expectations can negate ecological potential via altered pond management. Ultimately, SWPs are designed to protect downstream ecosystems, but a better understanding of the ecological processes within SWPs, and how management affects these processes, is needed to ensure they are protecting downstream water bodies.

ALTERATIONS OF DISSOLVED ORGANIC MATERIAL COMPOSITION AND ITS INFLUENCE ON ECOSYSTEM RESPIRATION [Oral Presentation]

Emily Taylor (Primary Presenter/Author)
University of Florida, etaylor21@ufl.edu;

Alexander Reisinger (Co-Presenter/Co-Author)
University of Florida, reisingera@ufl.edu;

Jacob Hosen (Co-Presenter/Co-Author)
Purdue University, jhosen@purdue.edu;

Abstract: Dissolved organic material (DOM) in urban streams can have increased lability, decreased aromaticity, and be of more autochthonous origin than in reference streams. Changes in DOM composition are important to understand as increasing labile DOM in reference streams can increase metabolic activity. More labile DOM in urban streams may be expected to increase metabolic activity, however, previous studies (and preliminary data from this study) have found lower respiration (R) rates in more urbanized sites. While DOM is known to contribute to ecosystem energetics, the relationship between substrate composition and its availability for aquatic organisms remains unclear and is further complicated by the multitude of anthropogenic stressors common to urban streams. We measured DOM composition and whole-stream metabolism of seven subtropical streams across an urbanization gradient over 20-months using fluorescence excitation-emission matrices and parallel factor analysis. In contrast to previous studies, we did not find urbanization as the strongest factor controlling DOM composition across sites. Instead, geomorphology, point sources, and in-stream processing were important factors. This suggests that controls on DOM composition of urbanized streams in subtropical environments may be different than temperate climates, where previous studies have been conducted.

BRIDGES - Barriers [or blips?] restricting illumination decreasing growth and energy in streams [Oral Presentation]

Andrea Fitzgibbon (Primary Presenter/Author)
Kent State University , afitzgib@kent.edu;

David Costello (Co-Presenter/Co-Author)
Kent State University, dcostel3@kent.edu;

Abstract: Bridge infrastructure is an understudied form of urbanization in stream networks, though road bridges are abundant in many landscapes (>1800 in Cuyahoga River watershed; ~1 bridge per square kilometer). The presence of bridges may be comparable to buried reaches if light to the benthos is restricted for an extended period (barrier) suppressing primary production, or comparable to open reaches if light to the benthos is only intermittently disrupted (blip). This study quantified how the presence of bridges changes ecosystem metabolism by benthic biofilms in streams. Whole stream metabolism was quantified using the two-station method and sensors distributed longitudinally, upstream, beneath, and downstream of each bridge. In streams with north-south oriented bridges, light was intermittently disrupted, and primary production was restricted by 0-3%. Streams with east-west oriented bridges disrupted light to the benthos in a fixed position and primary production was restricted by 17-24%. Streams with intercardinal oriented bridges disrupted light to the benthos with most variation and primary production was restricted by 26-42%. The extent to which bridges disrupt stream ecosystem processes can be either an extended barrier or a temporary blip depending on bridge orientation.

Classification of freshwater salinity regimes in urban streams across the United States [Oral Presentation]

Joanna Blaszczak (Primary Presenter/Author)
Global Water Center and Department of Natural Resources and Environmental Science, University of Nevada, Reno, jblaszczak@unr.edu;

Lauren Bolotin (Co-Presenter/Co-Author)
University of Nevada Reno, bolotinljb@gmail.com;

Abstract: Urbanization increases non-point source loading of major ions from human activities into freshwater ecosystems. While elevated salinity is a commonly documented phenomenon in urban streams draining watersheds with heavy winter road salt use and increased hydrologic connectivity through roads and subsurface piping, the spatial variability and inter-annual consistency of winter salinity extremes in streams draining cities across the U.S. is unclear. We classified annual regimes of specific conductance as a proxy of salinity in 39 U.S. Geological Survey stream monitoring locations draining urbanized watersheds across the U.S. using dynamic time warping and hierarchical clustering. Urban stream salinity regimes varied within regions and among years, pointing to high spatiotemporal variability as a key characteristic of urban stream chemistry. We used a random forest classifier to explore how catchment attributes including local climate and urban development characteristics predict cluster membership across space and time. Identifying critical locations and times of peak solute export from urbanized watersheds can inform efforts to mitigate the salinization of freshwater ecosystems.

DETECTION OF PER- AND POLYFLUOROALKYL SUBSTANCES (PFAS) IN GREAT LAKES FISH USING A NOVEL TECHNOLOGY [Oral Presentation]

Sarah Klepinger (Co-Presenter/Co-Author)
University of Notre Dame, Biological Sciences, skleping@nd.edu;

Graham Peaslee (Co-Presenter/Co-Author)
University of Notre Dame, gpeaslee@nd.edu;

Meghanne Tighe (Co-Presenter/Co-Author)
University of Notre Dame, Department of Chemistry and Biochemistry, mtighe@nd.edu;

Heather Whitehead (Co-Presenter/Co-Author)
University of Notre Dame, Department of Chemistry and Biochemistry, hwhitehe@nd.edu;

Alison Zachritz (Co-Presenter/Co-Author)
University of Notre Dame, Department of Biological Sciences, azachrit@nd.edu;

Gary Lamberti (Co-Presenter/Co-Author)
University of Notre Dame, glambert@nd.edu;

Whitney Conard (Primary Presenter/Author)
Department of Biological Sciences, University of Notre Dame, wconard@nd.edu;

Abstract: Per- and polyfluoroalkyl substances (PFAS) are man-made fluorinated organic chemical compounds resistant to degradation, making them extremely persistent in the environment and able to bioaccumulate in wildlife and humans. Traditional methods of PFAS analysis (LC-MS/MS) are time-consuming and expensive, but we applied a novel low-cost alternative in particle-induced gamma-ray emission spectroscopy (PIGE) to measure fluorine in fish tissue. PIGE is a rapid screening method that measures total organic fluorine in a sample as a surrogate for the 1000s of possible PFAS compounds in the environment. Our objectives for this study were: (1) determine the relationship between PIGE and traditional LC-MS/MS for fish tissues and (2) determine whether total fluorine in Lake Michigan sportfish differs across species, gender, and size (total length). Results show that Lake Michigan fish have elevated total organic fluorine concentrations compared to fish from Alaska with lower environmental fluorine exposure. Overall, our method development allows for rapid estimation of PFAS in fish as a screening tool from which selected samples can undergo analysis for specific compounds with LC-MS/MS. Our results contribute to a better understanding of the extent of PFAS contamination in aquatic food webs.

IMPACTS OF STREAM DAYLIGHTING ON HABITAT CONNECTIVITY – EXAMINING UNINTENDED CONSEQUENCES IN AN URBAN STREAM RESTORATION [Oral Presentation]

Chelsea Hintz (Primary Presenter/Author)
University of Cincinnati, hintzca@mail.uc.edu;

Ishi Buffam (Co-Presenter/Co-Author)
University of Cincinnati, ishi.buffam@uc.edu;

Michael Booth (Co-Presenter/Co-Author)
University of Cincinnati, michael.booth@uc.edu;

Abstract: Urban stream burial is a widespread practice in heavily developed urban areas. Stream burial changes key drivers of stream ecosystems – eliminating light, altering physical habitat within the buried reach, and reducing basal resources and macroinvertebrates. These alterations can alter connectivity within stream ecosystems by potentially increasing habitat fragmentation. Restoration projects often explicitly aim to restore connectivity within urban streams. Using a before-after-control-impact (BACI) study design, we are evaluating how the removal of a large (>100 m) culvert and restoration has influenced connectivity in an urban stream within Cincinnati, OH, USA. In particular, we are estimating near-term impacts on physical habitat characteristics, stream water physiochemistry, periphyton biomass, and macroinvertebrate density and diversity. Within the first 6 months of monitoring post-restoration, we found that stream daylighting led to substantial drying in the newly daylighted stream reach (which was perennial prior to restoration), increasing habitat fragmentation. Drying has reduced periphyton biomass in the newly daylighted channel when compared to the “before” period. Although reduced connectivity was an unintended short-term consequence of this restoration, long-term project effectiveness remains unclear, as evolution of the stream channel and riparian regrowth is ongoing.

NUTRIENT FLUX AT THE SEDIMENT-WATER INTERFACE IN URBAN RIVER IN LONDON AND BEIJING [Oral Presentation]

Meng Zhang (POC,Primary Presenter)
, meng.zhang@kcl.ac.uk;

Michael Chadwick (Co-Presenter/Co-Author)
King's College London, michael.chadwick@kcl.ac.uk;

Abstract: Uptake and regeneration of nitrate, ammonium, phosphate and dissolved organic carbon (DOC) at the sediment-water interface were evaluated at urban river sites in London and Beijing. London sites were located above and below a wastewater outfall, while Beijing sites encompassed a range of urban settings; together these sites provided a template to investigate a wide range of urban stressors. Using chamber techniques, water-specific nutrient concentrations were measured at 2 exposures (3 and 10 minutes) to calculate flux. Across all sites uptake and regeneration were found. For London, NO3- was -0.01 to +0.02 mg/(m2•s), NH4+ was -29 to +2 µg/(m2•s), PO43- was -2.0 to +0.5 µg/(m2•s), and DOC was -0.01 to +0.05 mg/(m2•s). For Beijing, NO3- was -0.40 to +0.21 mg/(m2•s), NH4+ was -2 to +20 µg/(m2•s), PO43- was -120 to +240 µg/(m2•s), and DOC was -0.02 to +0.22 mg/(m2•s). These results provide a baseline to investigate how urban stressors (e.g., pollution and elevated temperatures) affect nutrient flux. Our work illustrates how urban river conditions can affect the retention or release of nutrients, increasing the risks of eutrophication to downstream waterbodies.

PHARMACEUTICAL AND SOLUTE COCKTAILS IN BALTIMORE STREAMS [Oral Presentation]

Alexander Reisinger (Co-Presenter/Co-Author)
University of Florida, reisingera@ufl.edu;

Jerker Fick (Co-Presenter/Co-Author)
Umeå University, jerker.fick@umu.se;

Peter Groffman (Co-Presenter/Co-Author)
City University of New York, Peter.Groffman@asrc.cuny.edu ;

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

Megan Fork (Primary Presenter/Author)
Cary Institute of Ecosystem Studies, megan.fork@gmail.com;

Abstract: Pharmaceuticals, nutrients, and other solutes are some of the many anthropogenic chemical stressors faced by urban streams. We present analysis of twenty years of weekly solute concentrations overlapping with one year of weekly pharmaceutical concentrations in stream water from eight catchments spanning an urbanization gradient in Baltimore, MD. Despite none of the streams receiving direct effluent discharge from wastewater treatment, we frequently detected pharmaceuticals in these streams. The total number of pharmaceutical detections over the year at a given site was positively correlated with population density in the catchment, and the highest concentration of any pharmaceutical (3717 ng/L of acetaminophen) was found in a highly urbanized site furthest downstream. Repeated sampling revealed that pharmaceutical concentrations are highly dynamic over time, not correlated with stream discharge, and do not show synchrony among compounds. Over the 20-year record, minimum and median chloride concentrations increased at most sites, and intra-annual variability in many solutes was related to precipitation. Finally, we explore relationships between solutes, nutrients, and pharmaceuticals to better characterize and predict the complex chemical cocktails in these urban streams.

Quantifying substrate disturbance in urban streams [Oral Presentation]

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

Garrett Blauch (Co-Presenter/Co-Author)
AECOM, garrettblauch@gmail.com;

Andrew Blinn (Co-Presenter/Co-Author)
Kent State University, ablinn2@kent.edu;

Zia Ul Hassan (Co-Presenter/Co-Author)
Kent State University, zhassan1@kent.edu;

David Costello (Co-Presenter/Co-Author)
Kent State University, dcostel3@kent.edu;

Abstract: Disturbances to the stream ecosystem may occur when the geologic, biologic, and anthropogenic materials that comprise urban stream substrates are eroded and transported by high flows. Studies that attempt to understand how disturbance and restoration of flow regimes on ecosystem health must also consider the physical habitat that is being disturbed. Understanding the geomorphic processes that lead to substrate movement and ultimately ecosystem impairment depends not only on the hydrology, but also the nature of the materials being considered. Across a suite of urban streams in metropolitan Cleveland (Ohio), we are quantifying the movement of sediment, wood, and anthropogenic debris. Fine sediment and plastics are mobilized even in small storms, exhibit hysteresis within storms, and are mostly retained in association with large wood. Large storms that occur multiple times per year move coarse bed material, large wood, and heavier anthropogenic debris, but their supply is governed by catchment and riparian zone properties. Management of urban streams for ecosystem health requires making decisions based on understanding the linkages between the hydrologic and geomorphic processes that mediate substrate dynamics.

URBAN STRESSORS DRIVE FISH-BASED ECOLOGICAL NETWORKS IN STREAMS OF COLUMBUS, OHIO, USA [Oral Presentation]

S. Mažeika Patricio Sulliván (Primary Presenter/Author)
The Ohio State University, sullivan.191@osu.edu;

Jason R. Bohenek (Co-Presenter/Co-Author)
The Ohio State University, bohenek.3@osu.edu;

Carlos Cáceres (Co-Presenter/Co-Author)
The Ohio State University, carlos.l.caceres@gmail.com;

Laura W. Pomeroy (Co-Presenter/Co-Author)
The Ohio State University, pomeroy.26@osu.edu;

Abstract: Integrating network perspectives into stream research can reveal stressor effects and estimate taxonomic and functional community characteristics, thus representing a novel approach to stressor and connectivity paradigms in urban catchments. Using six years of data from twelve streams of Columbus, Ohio, USA, the effects of nutrients (N:P), impervious surface (%IS), and sedimentation on fish community network properties were quantified. All stressors impacted some properties of network topology – linkage density (number of links per species), connectance (fraction of possible links in network), and compartmentalization (degree to which networks contain sub-webs), including synergistic interactive effects between sedimentation and stream size. We also found support for antagonistic effects between (1) sedimentation and %IS and between %IS and N:P on the magnitude of trophic interactions among species, and (2) %IS and stream size on the distribution of total magnitude of all trophic interactions per species. Our results point to the potential for urban stressors to decrease network complexity, compartmentalization, and stability, likely by altering upstream-downstream connectivity, homogenizing habitat, and limiting food resources. The observation that larger streams often buffered negative stressor effects suggests that restoration might be most beneficial in smaller headwater streams.

DECOMPOSITION RATES OF LEAF, PALM, AND TURFGRASS DIFFER IN A SUB-TROPICAL URBAN STREAM [Poster Presentation]

Connor Morang (Primary Presenter/Author)
University of Florida, morangc@ufl.edu;

Abstract: Most headwater streams rely on allochthonous organic matter inputs to supplement energy produced internally from autochthonous sources. Allochthonous organic matter quality influences decomposition rates, subsequently affecting nutrient and food web dynamics within a stream. Land use change can influence the type and relative quality of allochthonous inputs. Lawns are prolific in urban and suburban landscapes, making turfgrass an increasingly common allochthonous organic matter source in urban streams. However, turfgrass decomposition in urban streams is poorly understood. We assessed how organic matter quality, macroinvertebrate presence, and light availability affected decomposition rates in an urban stream. We studied these factors by deploying oak leaves, turfgrass clippings, and palm fronds in either coarse or fine mesh bags at two different sites in an urban stream (one open canopy, one closed canopy). We calculated mass loss and percent organic matter change of these different treatments following a 4 month deployment. Preliminary results indicate that turfgrass, oak leaves, and palm fronds lost 80%, 28%, and 42% of their mass, respectively over 4 months. Understanding how shifts in organic matter affect decomposition rates is essential for furthering our knowledge of urbanization impacts on stream ecosystems.

Differential responses of algal-bacterial structure to wastewater in surface waters of the hydrologic contributing zone in the Edwards Aquifer Region [Poster Presentation]

Michelle Le (Primary Presenter/Author)
University of Texas at San Antonio, rtv121@utsa.edu;

Allison Veach (Co-Presenter/Co-Author)
University of Texas San Antonio, allison.veach@utsa.edu;

Abstract: Arid, intermittent streams in urban watersheds maintain flow through industrial and wastewater discharge. These water sources contain high concentrations of nutrients and a suite of contaminants which greatly impact stream structure and function. We deployed nutrient diffusing substrata (NDS) supplemented with N, P, N+P, and controls in three reaches impacted by wastewater discharge in Cibolo Creek, Boerne, TX. NDS Algal biomass, measured as chlorophyll-a, did not vary across nutrient treatments among sites indicating no nutrient limitation in algal communities spatially. Biofilm OM was greater in P and N+P treatments relative to controls at one site 1000-m downstream of wastewater discharge, but did not vary among nutrient regimes at the outfall or at the 5000-m downstream site. These data indicate that algae are not nutrient-limited in this ecosystem, yet heterotrophic microbial communities have greater P-demand than supply but this effect is dependent on site. This highlights the importance of spatial heterogeneity in influencing microbial nutrient demand in this ecosystem; nutrient input may also be supplied by non-point sources. Additional work is being completed to measure water-column nutrient concentrations and bacterial diversity colonizing NDS among sites.

EFFECTS OF LITTORAL VEGETATION ON PHYTOPLANKTON NUTRIENT LIMITATION AND COMMUNITY STRUCTURE IN SOUTH FLORIDA URBAN STORMWATER PONDS [Poster Presentation]

Alexander Reisinger (Co-Presenter/Co-Author)
University of Florida, reisingera@ufl.edu;

Ashley Smyth (Co-Presenter/Co-Author)
University of Florida, ashley.smyth@ufl.edu;

Michelle Atkinson (Co-Presenter/Co-Author)
UF IFAS Extension, michelleatkinson@ufl.edu;

Audrey Goeckner (Primary Presenter/Author)
University of Florida, agoeckner@ufl.edu;

Abstract: Urban stormwater wet ponds (SWPs) are common stormwater management systems that can experience algal blooms as a result of urban nutrient loadings. Traditional SWP designs often maintain turfgrass to the water’s edge, and do not allow for natural or ornamental vegetation in the littoral shelf. However, littoral vegetation may benefit urban ponds by reducing open-water nutrient (nitrogen (N), phosphorus (P)) availability and by providing habitat for phytoplankton consumers. Using in-situ bioassays, we quantified phytoplankton growth (biomass) and functional (N-fixation) responses to six nutrient treatments (control, NO3-, NH4+, PO43-, NO3-+PO43-, NH4++ PO43-) in SWPs with/without littoral vegetation. Phytoplankton biomass was quantified as chlorophyll-a concentrations and N-fixation rates assessed via membrane inlet mass spectrometry. We predict higher N limitation in vegetated ponds due to increased competition with macrophytic N uptake but that N+P combinations will support higher phytoplankton growth than N or P alone. Further, N treatments will exhibit lower N-fixation rates. This study can provide support for implementing biological management strategies that add aesthetic value, reduce nutrient runoff, and mitigate pond blooms harmful to public health.

How wastewater discharge is structuring communities in the urban Santa Ana River headwaters [Poster Presentation]

Kurt Anderson (Co-Presenter/Co-Author)
University of California, Riverside, kurt.anderson@ucr.edu;

William Ota (Primary Presenter/Author)
UC Riverside, williemota@gmail.com;

Abstract: The Santa Ana River runs through dense urban development, and common invasive species include largemouth bass, yellow bullhead, and mosquitofish. These species are frequently found in and around the wastewater discharge channels that maintain flow in the urban Santa Ana River. Wastewater discharge and invasive species are impacting native Santa Ana sucker survival. Invasive species, alongside effluent, are changing community structure in the Santa Ana River as novel biotic filters. We assessed the trophic niche of three common invasive species and Santa Ana sucker across two wastewater discharge channels. Bulk C/N isotope analyses show that there are significant differences in the invasive communities along the assessed reaches of the Santa Ana River. This work demonstrated differences in food web composition between the two discharge channels, and the same species held different isotopic niches in the two channels. Santa Ana sucker were determined to not be a significant food source in one of the two wastewater channels despite a lack of physical dispersal barriers. Future work will include further isotopic analysis to more fully examine how food webs are altered along the Santa Ana River's length.

Land-Use Effects on Decomposition Rates and Immobilization of Nutrients in Urban Streams [Poster Presentation]

Denzell Cross (Co-Presenter/Co-Author)
The University of Georgia, dacross@uga.edu;

Scott Tiegs (Co-Presenter/Co-Author)
Dept. of Biological Sciences, Oakland University, tiegs@oakland.edu;

Krista Capps (Co-Presenter/Co-Author)
University of Georgia, kcapps@uga.edu;

David Costello (Co-Presenter/Co-Author)
Kent State University, dcostel3@kent.edu;

Anthony Pignatelli (Primary Presenter/Author)
Kent State University, apignat2@kent.edu;

Abstract: Stream ecosystems provide key ecosystem services, but with increasing development, urban streams are at risk for nutrient pollution which can impact services. A cotton-strip assay was used to measure decomposition rate and nutrient uptake by decomposing microbes (i.e., immobilization) within 19 streams across the Chatahoochee and Ocmulgee River Basins in Metropolitan Atlanta, Georgia (USA). Decomposition rates were strongly correlated to phosphorus immobilization rates suggesting that nutrient supply influenced carbon cycling. Using GIS and satellite imagery, we analyzed land use patterns to identify potential sources of phosphorus. Overall impervious cover was positively correlated with decomposition and phosphorus immobilization, but much stronger relationships were observed with low intensity residential land areas . This suggests that increased rates of decomposition and immobilization could be due to lawn fertilizer application or an aging, obsolete water infrastructure, which are hypotheses for future study. Our study shows strong linkages between nutrient and carbon cycles in urban streams and suggests that elevated nutrient supply may impact carbon storage.

NITROGEN PROCESSING BY PRIMARY CONSUMERS ALONG AN URBANIZATION GRADIENT IN ANDEAN STREAMS [Poster Presentation]

Carlos Iñiguez Armijos (Primary Presenter/Author)
Departamento de Ciencias Biológicas, Universidad Técnica Particular de Loja, Ecuador, cainiguez@utpl.edu.ec;

Abstract: Urbanization implies permanent alterations in streams such as the depletion/loss of keystone species associated with ecosystem functions. Amongst the southern Ecuadorian Andes, we assessed the effects of urbanization on N processing by primary consumers in streams of a highly populated watershed. We quantify the Delta N (?15N) of scraper invertebrates as primary consumers, the dissolved inorganic nitrogen (DIN) in water, the benthic biofilm biomass, and the density of scraper invertebrates. Delta N of primary consumers decreased along the urbanization gradient while DIN and benthic biofilm biomass increased. No scraper invertebrates were found in the most urbanized streams. Our results suggest that the absence of primary consumers in the most urbanized streams is altering the N transformation impacting ecosystem functioning in Andean streams. Conserving and restoring riparian forests, as well as substrate and streamflow conditions, could provide a nature-based management approach to sustain nutrient processing and food webs in headwaters.

Riparian Spiders: A Sentinel Biosensor for Organic Contaminants? [Poster Presentation]

Jonathan Behrens (Primary Presenter/Author)
Duke University, jrb146@duke.edu;

Emily Bernhardt (Co-Presenter/Co-Author)
Duke University, emily.bernhardt@duke.edu;

Alyssa Mianecki (Co-Presenter/Co-Author)
University of Iowa, alyssa-mianecki@uiowa.edu;

Greg Lefevre (Co-Presenter/Co-Author)
University of Iowa, gregory-lefevre@uiowa.edu;

Dana Kolpin (Co-Presenter/Co-Author)
United States Geological Survey, dwkolpin@usgs.gov;

Heather Stapleton (Co-Presenter/Co-Author)
Duke University, heather.stapleton@duke.edu;

George Tait (Co-Presenter/Co-Author)
Duke University, george.tait@duke.edu;

Abstract: Most efforts to measure contaminants in streams and rivers are limited to single points in time or single contaminant classes, rather than prevalent mixtures known to often be present. This is due to the high temporal variation of contaminant water concentrations and the high costs to analyze. Biosensors may offer an inexpensive way of gaining an integrated sample of these chemical mixtures. We are investigating the potential to use predatory long-jawed orb weaving spiders, family Tetragnathidae, as a natural biosensor. Tetragnathidae were collected from the riparian zones of one stream and one river where detailed contaminant analyses are ongoing: pharmaceuticals in Muddy Creek near Iowa City, Iowa, and PFAS in the Haw River in North Carolina. Analyses compare the composition and concentration of targeted contaminants in spider tissues relative to surface water samples collected over a multi-year period. Our preliminary results allow us to determine which contaminants accumulate in spiders at concentrations above what is detected in water. We discuss how our findings should refine our approach to using spiders as biosensors for assessing contaminant loading in waterways and predict the risks posed to drinking water resources and sensitive wildlife.