5/24/2016  |   10:30 - 10:45   |  309-310

RAPID TURNOVER OF METHANOGENIC METHANE INFLUENCES CARBON SUPPLY AND INVERTEBRATE BIOMASS IN AN EXPANSIVE FLOODPLAIN AQUIFER Highly oligotrophic shallow alluvial aquifers of river floodplains, including the Nyack Floodplain of Northwest Montana, support diverse macroinvertebrates and meiofauna. These organisms are highly subsidized by modern and ancient methane despite low to immeasurable methane concentrations in the aquifer (<1 ?mol/L), providing a potential explanation for why the Nyack carbon budget is unbalanced. We used linear modelling and cluster analysis techniques to investigate spatiotemporal relationships between DOC (dissolved organic carbon), methane, dissolved oxygen (DO), and stonefly 13C and 15N. We characterized microbial communities using 16S rRNA analysis. Methane was the strongest predictor of DOC, suggesting that carbon fixation occurs; this was confirmed by the presence of hydrogenotrophic methanogens (up to 0.4% using 16S). Stonefly dietary niches were highly variable between well locations but averaged 66.5% methane dependence calculated using 13C values. Stonefly 13C values were not correlated with methane concentrations. We inferred that methanogenesis occurred at a fine spatial scale in the aquifer but methane was consumed rapidly, significantly influencing DOC supply and invertebrate biomass.

Amanda G DelVecchia (Primary Presenter/Author), Flathead Lake Biological Station - University of Montana, amanda.delvecchia@umontana.edu;


Jack A Stanford ( Co-Presenter/Co-Author), Flathead Lake Biological Station - University of Montana, jack.stanford@flbs.umt.edu;


Brian L Reid ( Co-Presenter/Co-Author), Centro de Investigación en Ecosistemas de la Patagonia (CIEP), brian.reid@ciep.cl;


Jon Graham ( Co-Presenter/Co-Author), University of Montana, jgraham@mso.umt.edu;


Bonnie Ellis ( Co-Presenter/Co-Author), Flathead Lake Biological Station-University of Montana, bonnie.ellis@umontana.edu;


Presentation:
This presentation has not yet been uploaded.

5/24/2016  |   10:45 - 11:00   |  309-310

CARBON AND NITROGEN FLUXES FROM ISOTOPICALLY-ENRICHED LEAF LITTER TO AQUATIC INSECT COMMUNITIES REVEAL DIFFERENCES IN LITTER QUALITY Although differences in litter decomposition rates from different tree species have been well documented we know less about whether the pathways of carbon and nitrogen in litter differ across species. Most studies testing for differences in energy fluxes among leaf types have been conducted in a laboratory setting focusing on large shredders. We created leaf packs using isotopically-enriched litter to measure carbon and nitrogen fluxes from litter from four riparian species to aquatic insect communities. Results indicate that shredding caddisflies and collecting mayflies tended to assimilate carbon at higher rates from slowly decomposing litter (oak and sycamore) whereas filter-feeding blackflies assimilated more carbon from rapidly decomposing Fremont litter. In contrast, nitrogen assimilation rates of a shredding caddisfly were negatively correlated with the initial litter C:N ratios. These results show that assimilation rates of C and N depend both on litter quality and decomposer species.

Adam Siders (Primary Presenter/Author), University of Florida, asiders@ufl.edu;


Zacchaeus Compson ( Co-Presenter/Co-Author), University of North Texas, zacchaeus.compson@unt.edu;


Jane Marks ( Co-Presenter/Co-Author), Northern Arizona University, jane.marks@nau.edu;


Presentation:
This presentation has not yet been uploaded.

5/24/2016  |   11:00 - 11:15   |  309-310

WATER-LAND LINKAGES: AN INQUIRY BASED LESSON ON EMERGENCE OF ADULT AQUATIC INSECTS AND THEIR IMPORTANCE TO TERRESTRIAL PREDATORS Traditionally, exploration of ecosystems has been restricted to connections within conventionally defined ecosystem boundaries (i.e., within a stream, within a forest). Further, the exploration of the aquatic-terrestrial interface has emphasized directional inputs from land to water. However, a relatively new body of research has characterized reciprocal interactions and draws attention to fluxes from water to land, including the emergence of aquatic insects that serve as prey for terrestrial predators. We present a guide to an inquiry-based lesson for undergraduate biology to explore the interactions and connections that propagate across aquatic and terrestrial habitat boundaries. The focus is on cross-habitat linkages within ecosystems, specifically, “What is the role of emergence in connecting aquatic and terrestrial habitats and organisms?” Students: 1) engage with a documentary film, 2) explore insect emergence and make observations of riparian insectivores, 3) explain the collected data, 4) elaborate on alternative study designs and a measure of ecosystem health, and 5) evaluate their new understanding. This lesson addresses core concepts and competencies for undergraduate biology education, identified in the Vision and Change, A Call to Action report.

Kaleb Heinrich (Primary Presenter/Author), University of Alabama, kheinrich@ua.edu;


Kelsey Robson ( Co-Presenter/Co-Author), Idaho State University, robskels@isu.edu;


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


Presentation:
This presentation has not yet been uploaded.

5/24/2016  |   11:15 - 11:30   |  309-310

SHIFTS IN FISH-CENTERED FOOD WEBS FOLLOWING DAM REMOVAL IN AN URBAN RIVER SYSTEM Dam removal, increasingly used as a restoration method in rivers, has been shown to act as an ecologically meaningful disturbance that can prompt significant shifts in fish assemblages, yet the implications for aquatic food webs remain largely unknown. We investigated the impacts of two lowhead dam removals on fish-centered food webs in a mid-sized river system of Columbus, Ohio. Upstream of the previous dams, species richness declined initially but increased in the second and third years following dam removal. However, shifts in the relative abundances of feeding guilds varied among the upstream reaches. In general, the proportion of top predators increased in both upstream and downstream reaches, but not until the third year following dam removal. Additional analysis using natural abundance stable isotopes (in progress) will generate estimates of food-chain length and mean trophic position, and further quantify food-web changes following dam removal. We anticipate that results from this research will improve current understanding of the ecological effects of dam removal as well as contribute to theory related to the effects of pulse disturbances on food-web dynamics.

Alayna Dorobek (Primary Presenter/Author), The Ohio State University, dorobek.1@osu.edu;


S. Mažeika Patricio Sulliván ( Co-Presenter/Co-Author), The Ohio State University, sullivan.191@osu.edu;


Presentation:
This presentation has not yet been uploaded.

5/24/2016  |   11:30 - 11:45   |  309-310

SEASONAL FISH MIGRATION SUPPLEMENTS A TROPHIC LEVEL IN A COASTAL LAKE MICHIGAN STREAM Native and introduced adfluvial fishes constitute a significant component of Great Lakes fisheries. Seasonal movement of adfluvial fish into coastal streams may deliver substantial amounts of energy that supplement coastal stream production. For example, Conte and Luttenton (unpublished data) noted that 40% of Brown trout would consume large numbers of larval suckers when available in the drift while 60% continued consuming invertebrates. Using bomb calorimetry, we determined the energy density of Chinook salmon muscle and eggs, larval White sucker, Steelhead eggs and adult aquatic insects (i.e. caddisfly and mayfly). Energy density of Chinook salmon male muscle, female muscle and eggs yielded 5,109 cal/g, 4,759 cal/g, and 6,209 cal/g respectively. Steelhead eggs were similar to Chinook eggs generating 6,211 cal/g. Larval White sucker energy content (5,726 cal/g) was significantly lower than adult caddisflies (6,743.2 cal/g). Adult mayflies yielded 5,277 cal/g. The high energy content and large runs of introduced salmon and steelhead has the potential to seasonally supplement the energy content of coastal streams; this can provide a valuable food source to resident fish and stimulate secondary production.

Emily Dean (Primary Presenter/Author), Grand Valley State University, deanem@mail.gvsu.edu;


Presentation:
This presentation has not yet been uploaded.

5/24/2016  |   11:45 - 12:00   |  309-310

KODIAK BROWN BEARS SURF THE SALMON RED WAVE: DIRECT EVIDENCE FROM GPS COLLARED INDIVIDUALS One of the goals of Ecosystems Base Fisheries Management (EBFM) is recognizing and mitigating indirect effects of fisheries on trophic interactions. Most research on indirect effects has considered how the abundance of managed fishes influences trophic interactions with other species. However, recent work has shown that attributes besides abundance, such as life history variation, can strongly mediate species interactions. Here, we present direct evidence of individual brown bears exploiting variation in sockeye salmon spawning phenology by tracking salmon runs across a 2,800 km2 region of Kodiak Island. Data from 40 GPS collared brown bears show bears visited multiple spawning sites in synchrony with the order of spawning phenology. The number of sites used was correlated with the number of days a bear exploited salmon, suggesting phenological variation in the study area influenced bear access to salmon, a resource which strongly influences bear fitness. These results underscore the need to understand how fisheries affect life history diversity in addition to abundance in order to minimize negative effects of fisheries management on non-target species, a goal of EBFM.

William Deacy (Primary Presenter/Author), Flathead Lake Biological Station, University of Montana, will.deacy@gmail.com;


Presentation:
This presentation has not yet been uploaded.