Wednesday, May 25, 2016
13:30 - 15:00

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13:30 - 13:45: / 304-305 MICRON-SCALE SPATIAL AND DIEL VARIATION IN OXYGEN AT THE BIOFILM-SEDIMENT INTERFACE

5/25/2016  |   13:30 - 13:45   |  304-305

MICRON-SCALE SPATIAL AND DIEL VARIATION IN OXYGEN AT THE BIOFILM-SEDIMENT INTERFACE Photosynthetic biofilms in streams influence element cycling through changes in physicochemical conditions over diel time scales. Through diffusion and advection, the products of algal metabolism may modify chemical speciation and ecosystem function in sediments. We quantified the magnitude of change in physicochemical gradients over diel periods in sediments underlying photosynthetic biofilms. Hourly micron-scale physicochemical depth profiles from the water column into sediment were collected using microelectrodes. Water column oxygen concentrations were quantified to characterize whole-stream metabolism. The sediment oxic layer was shallowest (15 mm) at nighttime and deepest (20 mm) between 16:00–18:00. Deepest oxic layer was concurrent with the time that sediment oxygen concentration was highest (80.6% saturation). Maximum sediment oxygen concentration was offset (~1 hour) from the maximum water column oxygen concentration (89.6%). The stream studied was slightly heterotrophic (NEP = -0.24 g O2/d/m2). Increased depth in sediment oxic layer suggests that algal biofilms can drive sediment physiochemistry over diel periods. Time lag in oxygen concentrations within sediments suggests that biogeochemical reactions favored under oxic conditions would be sustained at depth beyond the period of peak primary production.

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


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


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13:45 - 14:00: / 304-305 STIMULATION OF SAGINAW BAY CHAROPHYCEAN ALGAE BY P

5/25/2016  |   13:45 - 14:00   |  304-305

STIMULATION OF SAGINAW BAY CHAROPHYCEAN ALGAE BY P Charophycean algae can reach great abundance in the Laurentian Great Lakes, where their subsequent death, detachment, and shoreline deposition contribute to beach fouling. Traditional in-situ nutrient-diffusing substrata bioassays have shown that other types of Great Lakes benthic algae are frequently P-limited. However, the plant-like Charophycean algae do not colonize artificial nutrient-diffusing substrata, preventing the application of this technique to charophytes. I coupled fluorometric estimates of algal photosynthesis with short-term nutrient enrichment of charophytes collected from inner Saginaw Bay. Charophyte photosynthesis was frequently stimulated by P enrichment, suggesting that these algae were P-limited under natural conditions. Reduction of P loading may be an effective charophyte control measure, even in relatively light-poor and nutrient-rich areas of the Great Lakes.

Steve Francoeur (Primary Presenter/Author), Biology Department, Eastern Michigan University, steve.francoeur@emich.edu;


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14:00 - 14:15: / 304-305 STREAM METABOLISM INCREASES WITH DRAINAGE AREA AND PEAKS ASYNCHRONOUSLY ACROSS A STREAM NETWORK

5/25/2016  |   14:00 - 14:15   |  304-305

STREAM METABOLISM INCREASES WITH DRAINAGE AREA AND PEAKS ASYNCHRONOUSLY ACROSS A STREAM NETWORK We described the spatial and temporal patterns of stream metabolism across a stream network and examined their potential drivers. To investigate these patterns, we measured dissolved oxygen continuously for 11 months at 10 sites. We hypothesized 1) GPP and ER increased with stream size, 2) streams became less heterotrophic, and 3) GPP and ER were highest when available light and temperature were highest after high flows (spring-summer); but potential co-limiting environmental conditions that vary by site, drive seasonal patterns. We found that GPP and ER increased with drainage area as predicted by the RCC and that the stream network was largely heterotrophic except for few days in the spring and summer. We determined three seasonal patterns for GPP and two for ER. GPP peaked either in summer, winter or multiple times. ER peaked in the fall and winter. The spatial arrangement and temporal patterns of discharge, temperature, light and nutrients, and their relative importance resulted in asynchrony of the peaks of GPP and ER despite consistent regional climatic conditions across the stream network.

Francine Mejia (Primary Presenter/Author), U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Cascadia Field Station, fmejia@usgs.gov;


Joseph Benjamin ( Co-Presenter/Co-Author), USGS Forest and Rangeland Ecosystem Science Center, Corvallis, OR, jbenjamin@usgs.gov;


J. Ryan Bellmore ( Co-Presenter/Co-Author), Forest Service, Pacific Northwest Research Station, Juneau, AK, jbellmore@fs.fed.us;


Grace Watson ( Co-Presenter/Co-Author), Methow Salmon Recovery Foundation, Twisp, WA, grace@methowsalmon.org;


Adrianne Zuckerman ( Co-Presenter/Co-Author), University of Idaho, Moscow, ID, adriannez@gmail.com;


Michael Newsom ( Co-Presenter/Co-Author), US Bureau of Reclamation, Portland, OR, mnewsom@usbr.gov;


Alex Fremier ( Co-Presenter/Co-Author), Washington State University, alex.fremier@wsu.edu;


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14:15 - 14:30: / 304-305 APPLICATION OF CELLULAR AUTOMATA TO MODELING ALGAE BLOOM AND ITS ASSIMILATION PROCESS USING MULTI-RESOURCES OF DATA

5/25/2016  |   14:15 - 14:30   |  304-305

APPLICATION OF CELLULAR AUTOMATA TO MODELING ALGAE BLOOM AND ITS ASSIMILATION PROCESS USING MULTI-RESOURCES OF DATA Lakes eutrophication and consequent harmful algae blooms leads to potential threats to human health. Due to complex abiotic-biotic relations and spatial heterogeneity, algae bloom mostly exhibits spatial patchiness, which is hard to be described by general physical equations. In this study, a hybrid model which coupled a two-dimensional water quality module with an cellular automata (CA) based algae bloom module was developed to predict the algae spatiotemporal evolutions in a large Chinese lake. The water quality module provided hydrodynamic and nutrient conditions to algal bloom module. The CA paradigm was used in algae bloom module by taking advantage of its ability to present spatial heterogeneity and local interactions. To define CA rules, the kernel principle component analysis method was used to explore the relationships between algae blooming and the hydro-environmental factors. Data assimilation (Ensemble Kalman Filter) was implemented to update states and parameters of CA module, by using multi-source data from field observations and remote sensing images. The study indicated that the integrated model has great potentials in algal bloom modeling, and data assimilation could obviously improve the model performance.

Yuqing Lin (Primary Presenter/Author), Nanjing Hydraulic Research Institute, CHINA, yqlin@nhri.cn;


Qiuwen Chen ( Co-Presenter/Co-Author), Nanjing Hydraulic Research Institute, qwchen@nhri.cn;


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14:30 - 14:45: / 304-305 EXPERIMENTAL EFFECTS OF CONDUCTIVITY AND MAJOR IONS ON STREAM PERIPHYTON

5/25/2016  |   14:30 - 14:45   |  304-305

EXPERIMENTAL EFFECTS OF CONDUCTIVITY AND MAJOR IONS ON STREAM PERIPHYTON Our study examined if specific conductivities comprised of different ions associated with resource extraction affected stream periphyton assemblages, which are important sources of primary production. Sixteen artificial streams were dosed with two ion recipes intended to mimic sources and ranges of conductivity observed from field surveys. One recipe mimicked deep well brine [chloride salts dominating] and was dosed at five levels. The other reflected surface coal mine leachate [bicarbonate and sulfate salts dominating] and was dosed at four levels. Statistically significant changes in community structure occurred with increasing conductivity, but algal communities became more dissimilar to control treatments with increasing bicarbonate and sulfate than with increasing chloride concentrations. Measures of algal biomass were somewhat variable in the two treatments, but tended to increase with greater bicarbonate-sulphate concentrations. Possible dose-time interactions are being further explored, and dose response curves are being developed to further examine taxa responses to ion concentrations. Results indicate that periphyton communities respond to anthropogenic increases in conductivities, but responses may differ depending on the dominant ions comprising the conductivity.

Nathan Smucker (Primary Presenter/Author), U.S. Environmental Protection Agency, smucker.nathan@epa.gov;


Susanna DeCelles ( Co-Presenter/Co-Author), McConnell Group, Inc., decelles.susanna@epa.gov;


Stefania Guglielmi ( Co-Presenter/Co-Author), Pegasus Technical Services, Inc., guglielmi.stefania@epa.gov;


Christopher Nietch ( Co-Presenter/Co-Author), U.S. Environmental Protection Agency, nietch.christopher@epa.gov;


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