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SFS Annual Meeting

Tuesday, May 22, 2018
14:00 - 15:30

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14:15 - 14:30: / 320 EFFECTS OF CYANOBACTERIAL ALGAE BLOOMS ON SHORE FOOD WEBS OF LAKE ERIE AND THE MAUMEE RIVER

5/22/2018  |   14:15 - 14:30   |  320

EFFECTS OF CYANOBACTERIAL ALGAE BLOOMS ON SHORE FOOD WEBS OF LAKE ERIE AND THE MAUMEE RIVER Decades of research have shown that aquatic resources can subsidize terrestrial consumers living near the shores of streams, oceans, and lakes. Typically subsidies take the form of emergent aquatic insects consumed by terrestrial predators, or algal “sea wrack,” consumed by detritivores. But what if the subsidy is composed of cyanobcteria, which can be toxic, and are often assumed to be of low nutritional quality, despite sparse and often conflicting information justifying this assumption. Here we describe the nutritional quality of “wrack” washed ashore the Maumee River and Lake Erie, along a gradient of cyanobacterial algal bloom severity. We find that C:N and C:P of wrack decline with increasing bloom severity, suggesting cyanobacteria potentially represent a high quality nutrient source for riparian consumers. However, we also explore the toxicity of the wrack and the potential combined effects on growth rate and survival of consumers. Additionally, we discuss potential effects on riparian wildlife. Cyanobacterial algal blooms are becoming an increasing occurrence globally. Although effects on drinking water and aquatic ecosystems are key, potential impacts on riparian wildlife should not be neglected.

Kevin McCluney (Primary Presenter/Author), Bowling Green State University, kmcclun@bgsu.edu;


Neal Kolonay (Co-Presenter/Co-Author), Bowling Green State University, nealk@bgsu.edu;


Kaleigh Obrock (Co-Presenter/Co-Author), Bowling Green State University, kaleigo@bgsu.edu;


Andrea Fisher (Co-Presenter/Co-Author), Bowling Green State University, andfish@bgsu.edu;


Greg Gustafson (Co-Presenter/Co-Author), Bowling Green State University, ggustaf@bgsu.edu;


Amanda Martin (Co-Presenter/Co-Author), Bowling Green State University, amandkm@bgsu.edu;


Gabrielle Metzner (Co-Presenter/Co-Author), Bowling Green State University, gmetzne@bgsu.edu;


Karen Root (Co-Presenter/Co-Author), Bowling Green State University, kvroot@bgsu.edu;


Jocob Schoen (Co-Presenter/Co-Author), Bowling Green State University, jcschoe@bgsu.edu;


Melissa Seidel (Co-Presenter/Co-Author), Bowling Green State University, mseidel@bgsu.edu;


Tyler Turner (Co-Presenter/Co-Author), Bowling Green State University, tylernt@bgsu.edu;


John Woloschuk (Co-Presenter/Co-Author), Bowling Green State University, jwolosc@bgsu.edu;


Robert M. McKay (Co-Presenter/Co-Author), Bowling Green State University, rmmckay@bgsu.edu;


Timothy W. Davis (Co-Presenter/Co-Author), Bowling Green State University, timdavi@bgsu.edu;


Melanie Marshall (Co-Presenter/Co-Author), Bowling Green State University, melaniemarshall14@gmail.com;


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14:30 - 14:45: / 320 REGIONAL DIFFERENCES IN STREAM NETWORK GEOMETRY MEDIATE THE SPATIAL PATTERNING AND EXTENT OF AQUATIC-DERIVED RESOURCES IN TERRESTRIAL ENVIRONMENTS

5/22/2018  |   14:30 - 14:45   |  320

REGIONAL DIFFERENCES IN STREAM NETWORK GEOMETRY MEDIATE THE SPATIAL PATTERNING AND EXTENT OF AQUATIC-DERIVED RESOURCES IN TERRESTRIAL ENVIRONMENTS The redistribution of materials and energy across ecosystem boundaries suggests ex situ factors contribute to local food webs. Emergent insects develop in aquatic environments and shuttle resources to terrestrial systems as winged adults dispersing overland. The distance they travel from the stream is contingent the production and composition of the benthic macroinvertebrate community. At the watershed scale, the configuration of the entire river network could influence the amount of contact between aquatic and terrestrial systems and create locally intensified aquatic-terrestrial interactions. We estimated the proportion of a watershed receiving aquatic inputs from multiple stream sources for ~1,300 stream networks across the contiguous US and tested the relative roles of network geometry and several hydroclimate variables in defining these patterns. Up to 36% of the watershed could be subjected to 25% of the insect biomass exported form a stream and that the spatial extent was strongly related to stream network drainage density, which differed among ecoregions. This work complements theoretical developments with realistic stream networks sampled across a broad spatial extent and demonstrates the hydrogeomorphic template could constrain the spatial extent and patterning of aquatic resources in terrestrial ecosystems.

Darin Kopp (Primary Presenter/Author), University of Oklahoma, darinkopp@gmail.com;


Daniel Allen (Co-Presenter/Co-Author), University of Oklahoma, dcallen@ou.edu;


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14:45 - 15:00: / 320 RADIATION INCIDENCE IS NO COINCIDENCE: MODELING TERRESTRIAL CONTROL ON RIVER LIGHT ENVIRONMENTS

5/22/2018  |   14:45 - 15:00   |  320

RADIATION INCIDENCE IS NO COINCIDENCE: MODELING TERRESTRIAL CONTROL ON RIVER LIGHT ENVIRONMENTS Light availability is an important driver of seasonal variations in gross primary productivity (GPP) in rivers, yet there are only a handful of datasets with high frequency measurements of both GPP and light for rivers. Light regimes of rivers are often uncorrelated to patterns of incoming light due to attenuation both from the surrounding terrestrial landscape and in-stream changes in water clarity. Here, we focus on how the terrestrial landscape influences patterns in the light reaching the river surface. We developed a model to predict the seasonality of light incident at the river surface as a function of riparian phenology, channel geometry, and landscape topography. The model was tested by comparing predicted values to near-continuous in situ measurements at multiple sites with varying characteristics. Additionally, we used the model to experimentally test the relative importance of and interaction between individual controls on light availability. Accurate predictions of river light regimes permits assessing the role of light in mediating seasonal patterns of GPP at sites without existing light records. Additionally, the ability to generate predictions over large spatial scales facilitates examining patterns of GPP from a network perspective.

Philip Savoy (Primary Presenter/Author), Duke University, philip.savoy@gmail.com;


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


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


Lily Kirk (Co-Presenter/Co-Author), University of Florida, lily33@ufl.edu;


Matthew Cohen (Co-Presenter/Co-Author), University of Florida, mjc@ufl.edu;


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15:00 - 15:15: / 320 EXPOSURE-DEPENDENT TRANSFER OF METALS ACROSS INSECT METAMORPHOSIS DECOUPLES RISK IN LINKED AQUATIC-TERRESTRIAL FOOD WEBS

5/22/2018  |   15:00 - 15:15   |  320

EXPOSURE-DEPENDENT TRANSFER OF METALS ACROSS INSECT METAMORPHOSIS DECOUPLES RISK IN LINKED AQUATIC-TERRESTRIAL FOOD WEBS Aquatic insects link food web dynamics across freshwater-terrestrial boundaries and subsidize terrestrial consumer populations. Contaminants can determine the quality and quantity of such subsidies, yet the factors regulating their food web effects at the land-water interface are not well understood. To test how exposure concentrations impact trophic and metamorphic transfer of metals across the freshwater-terrestrial boundary, we conducted a large-scale field study of the accumulation patterns of trace metals through linked stream-forest food webs in the Colorado Rocky Mountains. We found that metals were transferred across trophic and metamorphic steps (i.e., aquatic vegetation to aquatic insect larvae, and larvae to adult) more efficiently from low metal streams, resulting in a disconnect between food web exposure in aquatic and terrestrial ecosystems. Although this pattern originated in the water, the relationship between aquatic and terrestrial tissue concentrations was lost at metamorphosis. These results have implications for both management of linked aquatic-terrestrial food webs and for utility of riparian organisms as indicators of certain aquatic contaminants. Furthermore, our findings bolster our working hypothesis that metamorphosis may be meaningfully viewed as a trophic process.

Johanna Kraus (Primary Presenter/Author), U.S. Geological Survey, jkraus@usgs.gov;


Richard Wanty (Co-Presenter/Co-Author), U.S. Geological Survey, rwanty@usgs.gov;


Travis S. Schmidt (Co-Presenter/Co-Author), U.S. Geological Survey, Fort Collins, CO 80526, tschmidt@usgs.gov;


David Walters (Co-Presenter/Co-Author), US Geological Survey, waltersd@usgs.gov;


Ruth Wolf (Co-Presenter/Co-Author), Perkin Elmer, ruth.wolf@perkinelmer.com ;


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15:15 - 15:30: / 320 DO ALGAE CARE ABOUT LIGHT AND NUTRIENTS?

5/22/2018  |   15:15 - 15:30   |  320

DO ALGAE CARE ABOUT LIGHT AND NUTRIENTS? Past research has shown a dynamic relationship for the influences of light and dissolved nutrients on stream algae. We posed the question: Can we predict instream responses in small streams when forests in riparian zones and catchments are modified? Many ecologists would predict that increased light into streams would result in increased algae and primary production. Biogeochemists might suggest the primacy of nutrient stoichiometry and limitation. Alternatively, biologists would ask about the influence of herbivores. Here we share findings from a large experimental study of epilithon activity and standing stocks, nutrients, and shade within food web context of the Trask River Watershed Study. We did not find consistent differences in chlorophyll a or epilithon standing stock among six clearcut watersheds and five forested reference watershed streams during pre- and post-harvest (5yr and 4yr) periods. Nutrient concentrations and molar ratios varied greatly among watersheds, and harvested watersheds showed increasing nitrate each year post-harvest. Small riparian buffers did not dampen the increase. Ammonium, DON, DOC and phosphorus did not increase post-harvest. We explore several models of alternative relationships among algae, light and nutrients that might help explain these results.

Sherri Johnson (Primary Presenter/Author), U.S. Forest Service, Pacific Northwest Research Station, sherrijohnson@fs.fed.us;


Alba Argerich (Co-Presenter/Co-Author), School of Natural Resources, University of Missouri, argericha@missouri.edu;


Linda Ashkenas (Co-Presenter/Co-Author), Oregon State University, linda.ashkenas@oregonstate.edu;


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