6/08/2017  |   09:00 - 09:15   |  305B

IMPACTS OF ENVIRONMENTAL CONCENTRATIONS OF TRICLOSAN ON COMPOSITION, FUNCTION, AND ANTIMICROBIAL RESISTANCE IN EPILITHIC BIOFILMS Triclosan is the active ingredient in antibacterial soaps that can reach detectable levels in waterways and is expected to have an impact on microbial-mediated ecosystem processes. We assessed the effect of triclosan on epilithic biofilms collected from Cattaraugus Creek, western New York. Biofilms were incubated for 3 weeks at four triclosan concentrations (0.0, 0.1, 1.0 and 10 ppb), representing the full range of concentrations observed in rivers and streams. Biofilm condition (chlorophyll a and AFDM) and function (photosynthesis, respiration, and extracellular enzyme activities) were measured post incubation. Triclosan significantly reduced biofilm chlorophyll content and autotrophic index relative to control, but did not appear to affect measured biofilm function. Interestingly, bacteria from the biofilms did not show triclosan resistance regardless of the treatment level. Subsequent assays indicate that culturable bacteria from the biofilms did not show reduced growth until triclosan concentrations reached 100 ppb. Our data suggests that field concentrations of triclosan may not be sufficient to reduce biofilm growth and function in rivers and streams.

David Kerling (Primary Presenter/Author), Canisius College, kerling1@canisius.edu;


Jonathan O'Brien ( Co-Presenter/Co-Author), Canisius College, obrien46@canisius.edu;


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6/08/2017  |   09:15 - 09:30   |  305B

IMPACT OF COAL MINE DRAINAGE ON STREAM MICROBIAL COMMUNITIES IN SOUTHERN WV We examined the impact of acid- and alkaline-mine drainage resulting from coal mining on the taxonomic and metabolic diversity of the microbial community in headwater streams in southern WV. Water samples were collected from six unimpaired streams, six streams impaired by alkaline-mine drainage, and five streams impacted by acid-mine drainage. Alkaline-mine drainage sites had elevated levels of alkalinity and sulfate. Acid-mine drainage sites had elevated sulfate and heavy metal concentrations with a pH below 5. The taxonomic composition of the microbial communities was examined using terminal restriction fragment length polymorphism (T-RFLP). Preliminary analysis showed that the number of bacterial operational taxonomic units (OTUs) was lower at sites impaired by alkaline-mine drainage, while the number of fungal OTUs was lower at acid-mine drainage sites. Multivariate analyses showed distinct clustering of the three site types for the bacterial community, but not for the fungal community. The overall metabolic activity and diversity of carbon sources (BIOLOG EcoPlates) utilized by bacteria was lower for alkaline-mine sites compared to unimpaired and acid-mine sites. Alteration of stream microbial communities may influence the breakdown of plant biomass.

Thomas Ford (Primary Presenter/Author), Concord University (Athens, WV), tford@concord.edu;


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6/08/2017  |   09:30 - 09:45   |  305B

SHORT AND LONG-TERM IMPACTS OF SALMON CARCASS DECOMPOSITION ON STREAM MACROINVERTEBRATE AND MICROBIAL COMMUNITY STRUCTURE Salmon runs are an important annual input of organic matter into headwater streams. In Michigan, Pacific salmon (Oncorhynchus spp.) have been introduced into the Great Lakes for commercial and recreational fisheries. Once spawning occurs, the resulting carcasses may have novel effects on the aquatic communities residing in these naïve headwater streams. The objective was to determine the effects organic matter decomposition on aquatic macroinvertebrate and microbial communities over time using a salmon carrion introduction model. Macroinvertebrate and microbial communities (epilithic biofilm and internal macroinvertebrate guts) were sampled at both introduction (downstream reach) and reference sites (upstream reach) before (September), during (October), and after (November to August) carrion introduction. The study was repeated to assess inter-annual variation (September 2014-August 2016). Overall, macroinvertebrate species diversity was not affected by carcass introduction, but epilithic biofilm communities had higher microbial diversity and relative abundance of cyanobacteria in the introduction reach (PERMANOVA, p<0.001). These data suggest a potential cascading effect through the foodweb by exogenous salmon carrion microbial communities. These foundational data highlight the importance of carrion in the microbial ecology of lotic systems.

Courtney Larson (Primary Presenter/Author), U.S. Environmental Protection Agency, larson.courtney@epa.gov;
U.S. EPA

Courtney Weatherbee ( Co-Presenter/Co-Author), Michigan State University, weath108@msu.edu;


Jennifer L. Pechal ( Co-Presenter/Co-Author), Michigan State University, pechalje@msu.edu;


Brandon Gerig ( Co-Presenter/Co-Author), Northern Michigan University, bgerig@nmu.edu;


Dominic Chaloner ( Co-Presenter/Co-Author), University of Notre Dame, dchalone@nd.edu;


Gary Lamberti ( Co-Presenter/Co-Author), University of Notre Dame, glambert@nd.edu;


M. Eric Benbow ( Co-Presenter/Co-Author), Michigan State University, benbow@msu.edu;


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6/08/2017  |   09:45 - 10:00   |  305B

PATTERNS AND DRIVERS OF ARID LAND AQUATIC MICROBIAL COMMUNITIES Aridification has driven significant environmental change in central Australia over millennia. Most of the Australian continent did not undergo Pleistocene glaciation, as experienced in the Northern Hemisphere. Instead, ongoing aridification has resulted in perennial freshwater systems in the arid interior being restricted to isolated groundwater-fed springs and a network of intermittently flowing rivers which contain isolated waterholes for most of each year. We recently completed the first study of the microbiomes of arid land springs and riverine waterholes. Our results suggest that local, rather than landscape, processes appear to be an important driver of community composition at these sites. We found that the composition of biofilm microbial communities varied greatly within a site, whilst the water column microbial communities were more homogenous and displayed considerable site fidelity. These results are in direct contrast with studies in Northern Hemisphere temperate streams where streambed biofilm microbial communities are less diverse than stream water microbial communities. A much larger spatial study (over the entire arid biome) is now planned to better understand the patterns and processes driving arid land aquatic microbial communities.

Jenny Davis (Primary Presenter/Author), Charles Darwin University, Jenny.Davis@cdu.edu.au;


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


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


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


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6/08/2017  |   10:00 - 10:15   |  305B

SALINITY AND PHOSPHURUS STRUCTURE BACTERIAL DORMANCY IN THE RARE BIOSPHERE OF FRESHWATER AND HYPERSALINE LAKES Dormancy is offered as a plausible explanation for the persistence of bacteria under suboptimal conditions. To identify the environmental cues triggering dormancy, bacterial activity needs to be investigated through times as taxa are pushed beyond their optimal conditions. We estimated seasonal bacterial dormancy patterns and identified the lake chemistry influencing activity in six lakes, varying in salinity (0.05% – 30.3%), over one year in Utah, USA. Using ribosomal RNA:DNA ratios as an indicator for bacterial activity, we found that within the rare biosphere the proportion of the community exhibiting dormancy was lower in hypersaline than freshwater lakes over the entire year. Based on our mixed effects models, saltier conditions (R2 = 0.89, F = 175.3, P < .001) and higher levels of total phosphorus (TP, R2 = 0.63, F = 37.07, P < .001) reduced the dormancy of rare taxa (relative abundance < 0.1%). Across the lakes, salinity and TP varied through the seasons, but other variables like TN and dissolved oxygen experienced more variation but had little effect on dormancy. Our results suggest that fluctuations in specific cues regulate dormancy contributing to seed banks of rare and inactive individuals.

Zachary Aanderud (POC,Primary Presenter), Brigham Young University, zachary_aanderud@byu.edu;


Tylan Magnusson ( Co-Presenter/Co-Author), Brigham Young University, ty.magnusson@gmail.com;


Alan Harker ( Co-Presenter/Co-Author), Brigham Young University, alan_harker@byu.edu;


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