SFS Annual Meeting

5/21/2018  |   11:00 - 11:15   |  330 B

IN SITU CHAMBER EXPERIMENTS REVEAL DRIVERS OF DISSOLVED NITROGEN AND PHOSPHORUS ATTENUATION DURING SUMMER IN THE TUKITUKI RIVER, NEW ZEALAND Instream attenuation alters downstream nutrient concentration and form but limited understanding of attenuation drivers limits source-to-sea water quality modelling. We investigated drivers in the Tukituki using in situ chambers, complimenting reach-scale measurements. Light influenced N dynamics more strongly than P dynamics. N areal uptake (U) and uptake velocity (Vf ) were significantly higher in light than dark for TDN and its components (NH4-N, NO3-N, DIN), except for DON. In contrast, uptake of TDP and DRP did not differ between light and dark. Release of DON and DOP made uptake of TDN and TDP lower than DIN and DRP, respectively. Drivers most strongly correlated with U DIN in the light were Nett Production > Gross Production > DRP > Chl. a > PAR. A regression model for U DIN (r2 = 60%) included initial DRP and Chl. a. DRP uptake was lower for cyanobacterial periphyton than filamentous greens and diatoms and had stronger relationships with environmental drivers than DIN uptake in the light when cyanobacteria data were excluded. Cyanobacteria had lower mass ratios of C/N and C/P than filamentous greens and diatoms, indicating greater internal nutrient reserves or different stoichiometric requirements.

John Quinn (Primary Presenter/Author), National Institute of Water and Atmospheric Research (NIWA), John.Quinn@niwa.co.nz;


Sherry Schiff (Co-Presenter/Co-Author), University of Waterloo, sschiff@waterloo.ca;


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5/21/2018  |   11:15 - 11:30   |  330 B

N PROCESSING PATTERNS THROUGH TIME AND SPACE: LINKING DIEL N DYNAMICS, UPTAKE, AND METABOLISM IN A LARGE RIVER Nitrogen (N) cycling in riverine systems, as compared to headwater streams, remains understudied, especially during winter and early spring seasons. To better understand wintertime riverine N cycling dynamics, we treated a six-month controlled nitrogenous fertilizer waste release into the Kansas River (conducted by the City of Lawrence, KS) as an ecosystem-scale nutrient addition experiment. Four in-situ nitrate sensors, paired with dissolved oxygen and photosynthetically active radiation sensors, were deployed across 32 km of the river from January to May 2018. Water column nitrate concentration followed a sinusoidal diel pattern both pre (0.50 – 0.70 mg-N/L, 28 November 2017) and post-addition (0.72 – 0.95 mg-N/L, 28 January 2018), suggesting that N cycling microbiota increased processing rates in response to N enrichment. We will examine the periodicity of these diel patterns, and how they change throughout the winter and into the spring months. We will also compare river metabolism, both upstream and downstream of the release point, to understand the effect of the N addition on overall riverine metabolism. This unique pairing of an ecosystem-scale N addition with high-frequency sensor data will increase our understanding of how a large river cycles N.

Michelle Catherine Kelly (Primary Presenter/Author), University of Kansas, michellekelly@ku.edu;


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


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5/21/2018  |   11:30 - 11:45   |  330 B

METABOLISM IN AN AGRICULTURAL STREAM: IMPACTED RIVERSCAPES RETAIN LONGITUDINAL COMPLEXITY Stream metabolism is an integrative measure of ecosystem function which is both a responder to and a driver of shifts in overall stream health. While metabolism is well understood in temperate systems, we know less about the spatial and temporal variability of metabolism in semi-arid regions. Marsh Creek, an agriculturally impacted stream in southeastern Idaho, is characterized by high turbidity, yet is still highly productive within the growing season. We measured daily ecosystem metabolism at 4 locations along ~75 km of Marsh Creek to understand within-stream controls on metabolism over one year with 3 additional sites during the growing season. Despite extensive stream modification and channelization, we find longitudinal heterogeneity in biomass, sedimentation, and nutrients such that GPP and ER varied as much over space as it did seasonally. We find different spatial and temporal drivers of metabolism. Contrary to our expectation that higher levels of turbidity would dampen GPP, we observed that turbidity was only a main driver of GPP at two of the seven sites. Our results reveal that complex interactions drive stream metabolism, even in highly modified landscapes.

Rebecca Hale (Co-Presenter/Co-Author), Smithsonian Environmental Research Center, haler@si.edu;
Rebecca Hale is an ecosystem ecologist who works at the interface of biogeochemistry, hydrology, and society. In addition to traditional ecological methods, she adapts concepts and tools from geography, sociology, and history to ask fundamental ecosystem ecology questions in non-traditional settings. She works within and across cities and rural areas at local to regional scales.

Colden Baxter (Co-Presenter/Co-Author), Idaho State University, baxtcold@isu.edu;


Benjamin Crosby (Co-Presenter/Co-Author), Idaho State University, crosby@isu.edu;


Sarah Stalder (Primary Presenter/Author), Idaho State University, stalsara@isu.edu;


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5/21/2018  |   11:45 - 12:00   |  330 B

MULTI-YEAR TRENDS IN SOLUTE CONCENTRATIONS AND FLUXES FROM A SUBURBAN WATERSHED: EVALUATING EFFECTS OF 100-YEAR FLOOD EVENTS Anthropogenic activities have increased solute concentrations and fluxes in rivers, contributed by changes in atmospheric deposition, road salt and fertilizer application, and urbanization. Extreme flood events, which are increasing in frequency, could alter river chemistry by flushing various solute reservoirs within the watershed. We evaluated changes in the concentrations and fluxes of inorganic nutrients, dissolved organic matter, and salts and major ions across a 12 to 15 year period that included two 100-year flood events. Over 12 to 15 year periods, concentrations and fluxes of sodium and chloride, fluxes of all other salts, and concentrations of dissolved organic carbon declined in our urbanizing watershed. Nitrate and DON appeared to be highly responsive to extreme flooding. Increasing trends in nitrate concentrations stabilized after the flood events. The concentration-discharge behavior of nitrate shifted from enrichment in the years prior to and including the floods to chemostasis after the floods. The capacity of large flood events to remove accumulated solutes within human-impacted watersheds has important implications for watershed management, and our results demonstrate an important role of extreme events in the biogeochemistry of urbanizing watersheds.

Ashley Coble (Primary Presenter/Author), National Council for Air and Stream Improvement, Inc., acoble@ncasi.org;


Adam Wymore (Co-Presenter/Co-Author), University of New Hampshire, adam.wymore@unh.edu;
Dr. Adam Wymore is a Research Assistant Professor at University of New Hampshire.

Michelle Shattuck (Co-Presenter/Co-Author), University of New Hampshire, Michelle.Shattuck@unh.edu;


Jody Potter (Co-Presenter/Co-Author), University of New Hampshire, jody.potter@unh.edu;


William H McDowell (Co-Presenter/Co-Author), University of New Hampshire, bill.mcdowell@unh.edu;


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5/21/2018  |   12:00 - 12:15   |  330 B

HOMOGENIZATION OF DISSOLVED ORGANIC CARBON IN THE SEDIMENT-WATER INTERFACE OF STREAMS Dissolved organic carbon (DOC) is a large carbon pool in surface waters and is critical to nutrient cycling, food webs, and water quality conditions. DOC is characterized in terms of quantity (i.e., concentration) and quality (i.e., biochemical composition) measurements. The quality measurements of DOC change with respect to the DOC origin in the landscape. In streams, the sediment-water interface (SWI) is an ecotone containing metabolic activity rates exceeding other locations in the landscape. Many studies have investigated changes in DOC quantity through the SWI, but quality assessments are rare. Here, we hypothesize that the SWI will homogenize the DOC quality signals regardless of DOC origin. We test this hypothesis with laboratory batch reactor experiments and field push-pull tests in SWI sediments of a lowland, mixed land use stream using DOC leachates from four carbon sources - elm leaves, tamarack needles, flocculent organic matter, and acetate. We then characterized the DOC quantity and quality changes that occurred within SWI. Initial results show that multiple optically-based DOC qualities had consistent responses to SWI conditions, regardless of DOC source, supporting the hypothesis that the SWI functions as a DOC homogenization site in watersheds.

Joseph Lee-Cullin (Primary Presenter/Author), Department of Earth and Environmental Sciences, Michigan State University, USA, cullinjo@msu.edu;


Jay Zarnetske (Co-Presenter/Co-Author), Department of Earth and Environmental Sciences, Michigan State University, jpz@msu.edu;


Rachel Geiger (Co-Presenter/Co-Author), College of the Environment, Western Washington University, WA, USA, geigerr@wwu.edu;


Tyler Hampton (Co-Presenter/Co-Author), Department of Earth and Environmental Sciences, Michigan State University, USA, thampton@msu.edu;


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5/21/2018  |   12:15 - 12:30   |  330 B

WARMING INDUCES ASYMMETRIC CONVERGENCE OF STREAM METABOLIC BALANCE Quantifying the temperature dependence of stream metabolism is critical for predicting how stream ecosystems will respond to climate warming. We modeled diel DO dynamics and estimated the activation energies of GPP and ER in streams distributed across six biomes of North America. The difference in the activation energies of GPP and ER, which describes the temperature dependence of GPP/ER, decreased with mean daily stream temperature and GPP/ER. This relationship allowed us to predict warming-induced changes in whole-stream GPP/ER as a function of stream temperature and current GPP/ER. We applied these relationships to a global compilation of stream metabolism and found that a 1 °C increase in stream temperature induced convergence in stream metabolic balance, realized as reduced inter-site variability in GPP/ER. GPP/ER in streams with higher current temperatures and GPP/ER is predicted to decrease in response to warming, whereas in streams with lower current temperatures and GPP/ER it is expected to increase, although by a smaller magnitude. We estimated a 23.6% increase (0.019 Pg/year) in carbon release from stream metabolism globally under a 1 °C increase in stream temperature.

Chao Song (Primary Presenter/Author), Taizhou University, songchaonk@163.com ;


Walter Dodds (Co-Presenter/Co-Author), Kansas State University, wkdodds@ksu.edu;


Janine Ruegg (Co-Presenter/Co-Author), Brandenburg University of Technology, jrueegg@GMAIL.COM;


Alba Argerich (Co-Presenter/Co-Author), University of Missouri, alba.argerich@oregonstate.edu;


Christina Baker (Co-Presenter/Co-Author), University of Alaska Fairbanks, clbaker5@alaska.edu;


William Breck Bowden (Co-Presenter/Co-Author), University of Vermont, breck.bowden@uvm.edu;


Michael Douglas (Co-Presenter/Co-Author), University of Western Australia & Charles Darwin University, michael.douglas@uwa.edu.au;


Kaitlin Farrell (Co-Presenter/Co-Author), University of Georgia, kfarrel@uga.edu;


Michael B. Flinn (Co-Presenter/Co-Author), Watershed Studies Institute, Dept. of Biological Sciences, Murray State University, mflinn@murraystate.edu;


Erica Garcia (Co-Presenter/Co-Author), Charles Darwin University, erica.garcia@cdu.edu.au;


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


Tamara Harms (Co-Presenter/Co-Author), University of California Riverside, tharms@ucr.edu;


Shufang Jia (Co-Presenter/Co-Author), Kansas State University, shufangj@ksu.edu;


Jeremy Jones (Co-Presenter/Co-Author), Univeristy of Alaska Fairbanks, jbjonesjr@alaska.edu;


Lauren Koenig (Co-Presenter/Co-Author), University of New Hampshire, lauren.koenig@unh.edu;


John S. Kominoski (Co-Presenter/Co-Author), Florida International University, jkominoski@gmail.com;


William H McDowell (Co-Presenter/Co-Author), University of New Hampshire, bill.mcdowell@unh.edu;


Damien McMaster (Co-Presenter/Co-Author), Charles Darwin University, Damien.McMaster@cdu.edu.au;


Samuel P. Parker (Co-Presenter/Co-Author), University of Vermont, samuel.parker@uvm.edu;


Amy D. Rosemond (Co-Presenter/Co-Author), University of Georgia, rosemond@uga.edu;


Claire Ruffing (Co-Presenter/Co-Author), University of British Columbia, ruffing.cathcart@ubc.ca;


Ken Sheehan (Co-Presenter/Co-Author), University of New Hampshire, ken.r.sheehan@gmail.com;


Matt Trentman (Co-Presenter/Co-Author), Flathead Lake Biological Station, University of Montana, matt.trentman@flbs.umt.edu;


Matt Whiles (Co-Presenter/Co-Author), University of Florida, mwhiles@ufl.edu;


Wilfred M. Wollheim (Co-Presenter/Co-Author), University of New Hampshire, wil.wollheim@unh.edu;


Ford Ballantyne (Co-Presenter/Co-Author), University of Georgia, fb4@uga.edu;


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