Thursday, May 21, 2015
10:30 - 12:00

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10:30 - 10:45: / 101B THE EFFECT OF DISPERSAL BARRIERS ON STREAM FISH AND INSECT ASSEMBLAGES IN URBAN LANDSCAPES

5/21/2015  |   10:30 - 10:45   |  101B

THE EFFECT OF DISPERSAL BARRIERS ON STREAM FISH AND INSECT ASSEMBLAGES IN URBAN LANDSCAPES The urban stream syndrome describes the numerous, potentially interacting pathways that urbanization alters stream ecosystem structure and function. Human-altered landscapes can also fragment natural habitats, create environmental sinks, and include direct barriers to movement that affect dispersal. We examined the ability of land use/cover in the catchment and features of the broader landscape that affect dispersal (e.g., road crossings, impervious cover) to predict the composition of fish and insect assemblages in streams along an urbanization gradient in Massachusetts. We divided the catchment and broader landscape into overlapping and non-overlapping sections for analysis to minimize the effect of spatial autocorrelation of land-use variables among spatial extents. We compared model fit of regressions of individual landscape predictors and community response variables across multiple spatial scales to determine the spatial scale for analysis. We found that catchment land use had a greater effect on assemblage variables than landscape variables representing dispersal barriers. However, landscape variables were also significant predictors, suggesting that features affecting dispersal may be important drivers of fish and macroinvertebrate assemblages and may be useful to guide land conservation decisions.

Robert Smith (Primary Presenter/Author), Lycoming College, rsmith729@gmail.com;


Allison Roy (Co-Presenter/Co-Author), U.S. Geological Survey, Massachusetts Cooperative Fish and Wildlife Research Unit, University of Massachusetts Amherst, aroy@eco.umass.edu;


10:45 - 11:00: / 101B DOES URBAN TREE CANOPY ENHANCE NUTRIENT EXPORT BY STORMWATER?

5/21/2015  |   10:45 - 11:00   |  101B

DOES URBAN TREE CANOPY ENHANCE NUTRIENT EXPORT BY STORMWATER? Development of urban tree canopy is often prescribed as a stormwater management strategy due to the ability of trees to reduce stormwater volumes through interception of rainfall. However, trees also potentially contribute to nutrient export in stormwater through deposition of leaf litter onto streets, which are usually directly connected to storm drainage networks and therefore to receiving lakes and streams. We address the potential influence on stormwater nutrient fluxes of tree canopy over and near streets through analysis of high-resolution land cover data and several years of water quality monitoring data for several primarily-residential urban watersheds across Minneapolis-St. Paul, MN. We find a positive correlation between canopy cover over streets and stormwater phosphorus and suspended solids across watersheds. At the smaller scale of a 20-ha residential watershed, we illustrate the importance of tree species and canopy coverage of impervious surfaces through sampling of catch basins and rainfall-runoff in gutters of individual blocks. The results imply that urban water quality management may need to consider tree species selection in managed boulevards as well as improved timing of street sweeping.

Benjamin Janke (Primary Presenter/Author), University of Minnesota, janke024@umn.edu;


Jacques Finlay (Co-Presenter/Co-Author), University of Minnesota, jfinlay@umn.edu;


Sarah Hobbie (Co-Presenter/Co-Author), University of Minnesota, shobbie@umn.edu;


11:00 - 11:15: / 101B DEVELOPING ECOLOGICAL INDICATORS FOR NUTRIENTS AND URBAN IMPACTS TO STREAMS IN COASTAL WATERSHEDS

5/21/2015  |   11:00 - 11:15   |  101B

DEVELOPING ECOLOGICAL INDICATORS FOR NUTRIENTS AND URBAN IMPACTS TO STREAMS IN COASTAL WATERSHEDS Increased nutrient loads associated with human activities are among leading causes of impairment to streams and receiving waterbodies. For streams draining to the environmentally and economically important Narragansett Bay estuary, we developed indicators based on (1) nitrogen and carbon stable isotope ratios of periphyton and macroinvertebrates and (2) microbial enzyme activities. Streams tended to be P limited, as indicated by nutrient concentrations and high microbial phosphatase activity that decreased as TP concentrations increased. Nitrate concentrations significantly increased with human sources associated with urban land cover. Increased nitrate concentrations were significantly correlated with greater δ15N in periphyton and macroinvertebrate scrapers, detritivores, and predators, making these potentially useful indicators that also provide insight into changes in food webs. Microbial respiration decreased as the ratio of glycosidases to oxidases decreased, potentially indicating lower quality of DOC in urban streams. Stable isotopes and macroinvertebrate communities indicated that vegetated riparian buffers likely had benefits for ecological communities, even in moderately urban streams. Lastly, landscape indicators are being developed using GIS to characterize how spatial patterns of land cover are linked to stream conditions.

Nathan Smucker (Primary Presenter/Author), Oak Ridge Institute for Science and Education Participant, smucker.nathan@gmail.com;


Anne Kuhn (Co-Presenter/Co-Author), Environmental Protection Agency, kuhn.anne@epa.gov;


Mike Charpentier (Co-Presenter/Co-Author), Raytheon Company, charpentier.mike@epa.gov;


Carlos Cruz-Quinones (Co-Presenter/Co-Author), University of Puerto Rico, cruz.carlosjuan@gmail.com;


Colleen Elonen (Co-Presenter/Co-Author), Environmental Protection Agency, elonen.colleen@epa.gov;


Brian Hill (Co-Presenter/Co-Author), Environmental Protection Agency, hill.brian@epa.gov;


Jim Lake (Co-Presenter/Co-Author), Environmental Protection Agency, lake.jim@epa.gov;


Jonathan Serbst (Co-Presenter/Co-Author), Environmental Protection Agency, serbst.jonathan@epa.gov;


11:15 - 11:30: / 101B LONG-TERM VARIATIONS IN WATER QUALITY IN AN URBAN RIVER IN THE UNITED KINGDOM

5/21/2015  |   11:15 - 11:30   |  101B

LONG-TERM VARIATIONS IN WATER QUALITY IN AN URBAN RIVER IN THE UNITED KINGDOM The spatial and temporal trends of water quality of an urbanised river, River Medlock (Greater Manchester, UK) were studied in relation to point-source inputs, specifically combined sewer overflows (CSOs) and water-water treatment works (WWTWs). Water quality data for six physical and chemical parameters from three monitoring stations was collected from 2000 to 2013 by the UK’s Environment Agency. A one-way ANOVA was employed to evaluate the spatial variation of water quality for each station. The results showed that there were significant spatial differences for the nitrate and phosphate and that a strong correlation between the two suggests a point source, probably the WWTWs. Conductivity and biochemical oxygen demand do not show a spatial trend to we ascribe this to the effective treatment of the organic load by the WWTWs and the absence of inputs from CSOs. Temporal analysis revealed improving water quality including a reduction in the phosphate load. This study suggests long-term spatial and temporal variations of river quality are informative for water quality decision making processes.

Cecilia Medupin (Primary Presenter/Author), UNIVERSITY OF MANCHESTER, cecilia.medupin@manchester.ac.uk;


11:30 - 11:45: / 101B PATTERNS OF STORMFLOW DISSOLVED ORGANIC MATTER CONCENTRATION, COMPOSITION, AND TIMING IN THREE SMALL URBAN STREAMS

5/21/2015  |   11:30 - 11:45   |  101B

PATTERNS OF STORMFLOW DISSOLVED ORGANIC MATTER CONCENTRATION, COMPOSITION, AND TIMING IN THREE SMALL URBAN STREAMS Impervious surface cover (ISC; i.e. roads, parking lots) and subsurface connectivity via stormwater pipes increase the flashiness of streams in urban relative to undeveloped watersheds. This increased flashiness delivers pulses of dissolved organic matter (DOM) to urban streams during storms that are likely ‘shunted’ downstream in stormflow. Concentrations of DOM tend to be higher in urban as compared to reference streams, and urban DOM has been characterized as more labile. However, the role of subsurface connectivity via pipes versus surface connectivity of ISC is not well resolved. Here, we compare the concentration and composition of DOM in stormflow among three small urban streams in Durham, NC that have similar %ISC in their watersheds, but with nearly four-fold difference in subsurface pipe densities (ranging from 1082 to 4065 m/ha). The timing and magnitude of stormflow DOM differ among these watersheds, with more marked pulses in streams with greater pipe density. We also use EEMs and PARAFAC modeling to quantify changes in the composition of colored DOM over the course of storms and compare composition of stormflow and baseflow colored DOM.

Megan Fork (Primary Presenter/Author), West Chester University, mfork@wcupa.edu;


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


Jim Heffernan (Co-Presenter/Co-Author), Duke University, james.heffernan@duke.edu;


Dean Urban (Co-Presenter/Co-Author), Duke University, deanu@duke.edu;


11:45 - 12:00: / 101B NITROUS OXIDE YIELDS FROM URBAN STORMWATER PONDS IN 8 US CITIES

5/21/2015  |   11:45 - 12:00   |  101B

NITROUS OXIDE YIELDS FROM URBAN STORMWATER PONDS IN 8 US CITIES Stormwater ponds are being created and modified throughout US cities with unclear biogeochemical consequences. The high temperatures, low oxygen and high nitrate typical of these urban water bodies should provide ideal conditions for denitrifying microbial communities, and as a result stormwater ponds may be major sources of both N2O and N2 fluxes within urban landscapes. During the summer of 2014, we collected sediments and measured potential N2O and N2 production from 4 highly urban and 4 ‘green space’ ponds within 8 USA metropolitan statistical areas (MSAs). We found tremendous variation in N2O and N2 potential production rates both within and across cities, with N2O rates ranging from 0.002 to 37.6 µg N2O g-1 hr-1 and N2 rates ranging from 0 to 44.2 µg N2 g-1 hr-1. N2O accounted for as little as 0.01% to as much as 99% of total gaseous N fluxes. There were no consistent differences in N fluxes between high density and green space ponds. Instead, we found that microbial biomass was the single best predictor of total gaseous N fluxes (R2=0.19; p<0.001).

Joanna Blaszczak (Primary Presenter/Author), University of Nevada, Reno, jblaszczak@unr.edu;


Meredith Steele (Co-Presenter/Co-Author), Virginia Polytechnic Institute and State University, steelem@vt.edu;


Sarah Hobbie (Co-Presenter/Co-Author), University of Minnesota, shobbie@umn.edu;


Brian Badgley (Co-Presenter/Co-Author), Virginia Polytechnic Institute and State University, badgley@vt.edu;


Jim Heffernan (Co-Presenter/Co-Author), Duke University, james.heffernan@duke.edu;


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


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