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SFS Annual Meeting

Wednesday, May 22, 2019
09:00 - 10:30

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09:00 - 09:15: / 151 G DO ATTRIBUTES OF DRYING MATTER? SHORT-TERM RECOVERY OF SEDIMENT METABOLISM FROM VARIOUS DRYING

5/22/2019  |   09:00 - 09:15   |  151 G

DO ATTRIBUTES OF DRYING MATTER? SHORT-TERM RECOVERY OF SEDIMENT METABOLISM FROM VARIOUS DRYING Little is known about the effect of flow intermittence on temperate rivers that experience more infrequent and less intense drying than those in arid zones. We apply concepts from soil rewetting to assess the significance of drying attributes on the short-term recovery of sediment metabolism upon flow resumption. During summer 2018, in 56 outdoor mesocosms, we exposed sandy sediments from the banks of a temperate river (Spree river, Germany); half of the mesocosms were enriched with local allochthonous organic matter (OM). We simulated 9 drying scenarios differing in attributes: duration (10, 30 and 90 days) and intensity: (no shade + no rain) > (no shade + rain) > (shade + rain). At the end of each duration and for each intensity, flow resumption was simulated perfusing the sediment with river water. Drying attributes and OM modulated the short-term recovery. For 10- and 30-days duration, regardless of OM and intensity, an immediate response was observed, while 90-days and intense drying with low OM resulted in a lagged short-term recovery. Our results suggest that, as observed in soils under rewetting, the metabolism of riverbed sediments is resilient depending on drying attributes.

Jose Schreckinger (Primary Presenter/Author), Brandenburg University of Technology Cottbus-Senftenberg, jischreck88@gmail.com;


Clara Mendoza-Lera (Co-Presenter/Co-Author), National Research Institute of Science and Technology for Environment and Agriculture, Lyon, France, clara.mendozalera@gmail.com;


Michael Mutz (Co-Presenter/Co-Author), Department of Freshwater Conservation, BTU-Cottbus Senftenberg, m.mutz@b-tu.de;


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09:15 - 09:30: / 151 G EFFECTS OF SIMULATED DROUGHT ON AQUATIC INSECT COMMUNITIES IN THE EASTERN SIERRA NEVADA

5/22/2019  |   09:15 - 09:30   |  151 G

EFFECTS OF SIMULATED DROUGHT ON AQUATIC INSECT COMMUNITIES IN THE EASTERN SIERRA NEVADA As climate-induced flow variability increases in our riverine systems, some rivers with historically perennial flow regimes in the Sierra Nevada Mountains are becoming intermittent. We simulated future flow loss in this region by utilizing a set of nine experimental stream channels at the Sierra Nevada Aquatic Research Laboratory (SNARL). We conducted an experimental drought study subjecting the aquatic benthic insect community to various levels of flow reduction. We sampled the invertebrate community several times before, during, and after drought treatments were in effect. We were especially interested in how drought would affect invertebrate persistence and beta-diversity at SNARL, given that aquatic taxa in high elevation regions are adapted to a perennial hydrograph. Contrary to predictions, taxa at SNARL exhibited high resistance to drought stress until surface flow in the streams was lost. In terms of beta-diversity, community dissimilarity was maintained (turnover), while strong abundance gradients (nestedness) emerged through drought treatments and time. The results of our study highlight the importance of sustained surface flow in perennial systems.

Dave Herbst (Co-Presenter/Co-Author), Sierra Nevada Aquatic Research Laboratory, University of California Santa Barbara, david.herbst@lifesci.ucsb.edu;


Bruce Medhurst (Co-Presenter/Co-Author), Sierra Nevada Aquatic Research Laboratory, University of California Santa Barbara, rbmedhurst@ucsb.edu;


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


Parsa Saffarinia (Primary Presenter/Author), University of California, Riverside, psaff001@ucr.edu;


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09:30 - 09:45: / 151 G INPUTS FROM WASTEWATER TREATMENT PLANT EFFLUENTS INFLUENCE THE TEMPORAL VARIATION OF NUTRIENT UPTAKE IN A TEMPORARY STREAM

5/22/2019  |   09:30 - 09:45   |  151 G

INPUTS FROM WASTEWATER TREATMENT PLANT EFFLUENTS INFLUENCE THE TEMPORAL VARIATION OF NUTRIENT UPTAKE IN A TEMPORARY STREAM Effluents from wastewater treatment plants (WWTP) are sources of nutrients, organic matter, emergent contaminants, and bacteria for receiving streams. WWTP inputs affect stream chemical conditions as well as in-stream nutrient uptake capacity, altering the amount and fate of nutrients exported. In regions with water scarcity, such as the Mediterranean region, the influence of WTTP inputs on receiving streams can vary broadly over seasons because the stream hydrological regime is intermittent while WWTP inputs remain relatively constant over time. Our aim was to examine the influence of inputs from a WWTP on the temporal variation of nutrient uptake of a temporary receiving stream. To do so, we analyzed data collected during a 10-year period that encompassed a wide range of hydrological conditions. Results showed higher in-stream bioreactivity for nitrogen than for phosphorus. In particular, the stream was a hot spot of nitrification. We also found a high temporal variation of nitrogen uptake, which was lower during low flow conditions when the WWTP influence was higher. Management strategies should consider the interplay between WWTP operation and stream biogeochemical functioning and its temporal variation to improve stream water quality in urban landscapes.

Eugènia Martí (Primary Presenter/Author), Center for Advanced Studies of Blanes (CEAB-CSIC), eugenia@ceab.csic.es;


Sara Castelar (Co-Presenter/Co-Author), Center for Advanced Studies of Blanes (CEAB-CSIC), saracastelar@hotmail.com;


Miquel Ribot (Co-Presenter/Co-Author), Center for Advanced Studies of Blanes (CEAB-CSIC), mribot@ceab.csic.es;


Stephanie N. Merbt (Co-Presenter/Co-Author), EAWAG, stephanie.merbt@eawag.ch;


Marta Tobella (Co-Presenter/Co-Author), Universitat de Barcelona, tobella.marta@gmail.com;


Francesc Sabater (Co-Presenter/Co-Author), Universitat de Barcelona, fsabater@ub.edu;


Esperança Gacia (Co-Presenter/Co-Author), Center for Advanced Studies of Blanes (CEAB-CSIC), gacia@ceab.csic.es;


Jennifer Drummond (Co-Presenter/Co-Author), Center for Advanced Studies of Blanes (CEAB-CSIC), j.drummond@ceab.csic.es;


Susana Bernal (Co-Presenter/Co-Author), Center for Advanced Studies of Blanes (CEAB-CSIC), sbernal@ceab.csic.es;


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09:45 - 10:00: / 151 G DROUGHT-INDUCED MASS MORTALITY OF FRESHWATER MUSSELS ALTERS ECOSYSTEM FUNCTION: A MESOCOSM EXPERIMENT

5/22/2019  |   09:45 - 10:00   |  151 G

DROUGHT-INDUCED MASS MORTALITY OF FRESHWATER MUSSELS ALTERS ECOSYSTEM FUNCTION: A MESOCOSM EXPERIMENT Droughts are becoming more frequent and intense globally, threatening organisms with limited mobility. As ecosystem engineers, the loss of freshwater mussels has profound impacts on stream ecosystems; as sedentary animals, mussels are sensitive to drought. Thus, we conducted a mesocosm experiment that simulated a mussel die-off and responses of measures of ecosystem function. We created three scenarios: control mesocosms, mesocosms with a live mussel community, and mesocosms with a mussel community that experienced a die-off. We measured water column nutrients (NH4-N and SRP), benthic primary production, decomposition, and the macroinvertebrate community before and after the mussel mortality event. After die-off, nutrients increased in mortality mesocosms with ammonium increasing by 94%. The rapid nutrient release following mussel mortality stimulated both autotrophs and heterotrophs. Benthic primary production and organic matter decomposition increased in the mortality mesocosms. We combined our results with a literature review to build a conceptual model of how unionid mass mortality events impact ecosystem function across multiple time scales. We predict that droughts simplify the mussel community, which reduces ecosystem function for years to decades through the loss of filtration capacity, nutrient recycling and storage, and habitat.

Traci DuBose (Primary Presenter/Author), University of Oklahoma, tracipopejoy@ou.edu;


Carla Atkinson (Co-Presenter/Co-Author), The University of Alabama, carla.l.atkinson@ua.edu;


Caryn Vaughn (Co-Presenter/Co-Author), University of Oklahoma, cvaughn@ou.edu;


Stephen W. Golladay (Co-Presenter/Co-Author), J.W.Jones Research Center, steve.golladay@jonesctr.org;


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