SFS Annual Meeting

5/24/2018  |   14:00 - 14:15   |  330 A

HUMAN TRASH AND MICROBIAL TREASURES: DISTINCT PATTERNS OF MICROBIAL BIOFILM SUCCESSION ON PLASTIC LITTER SURFACES Plastics production and disposal rates are accelerating. Discarded plastics can accumulate in terrestrial and riverine systems before transport to global oceans. Microbial biofilms on natural substrates in streams (wood, sediments, and rocks) show distinct biofilm community composition, metabolism, and nutrient uptake rates. Plastics are a novel and abundant substrate for microbial biofilms to colonize in lotic ecosystems. Thus, accrual of plastic litter in lotic ecosystems could affect biofilm-mediated ecological processes. We incubated common plastic polymer types (PVC, polyethylene, polystyrene) and unglazed clay tiles in the North Branch of the Chicago River over 5 weeks to measure the effect of plastic litter type on biofilm colonization rates, community composition, and ecosystem function. All materials were colonized at similar rates to a similar magnitude, but polyethylene and PVC selected for autotrophic-dominated communities, while polystyrene and clay tile selected for heterotrophic-dominated communities. Differences in respiration emerged early in succession and persisted through biofilm maturation, but became less apparent as the biofilm senesced. Some plastic polymers host microbial biofilms that function differently than those on natural surfaces, which reveal controls on biofilm succession and suggest the potential for effects at larger spatial scales.

Samuel Dunn (Primary Presenter/Author), Loyola University Chicago , sdunn3@luc.edu;


Anna Vincent (Co-Presenter/Co-Author), University of Notre Dame, avincen5@nd.edu;


Timothy Hoellein (Co-Presenter/Co-Author), Loyola University Chicago, thoellein@luc.edu;
Dr. Hoellein is a freshwater ecologist at Loyola University Chicago. His research interests are focused on ecosystem processes and biogeochemistry. His research lab explores these areas in associate with the movement and biological transformation of elements, energy, and pollution in aquatic ecosystems.

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5/24/2018  |   14:15 - 14:30   |  330 A

BIOFILM ACCUMULATION MEDIATES THE TRANSPORT OF GENETICALLY-ENGINEERED PROTEIN (CRY1AB) IN EXPERIMENTAL STREAMS The majority of corn planted in the US is genetically-engineered, expressing insecticidal proteins such as Cry1Ab, in order to prevent crop damage by the European corn borer. As maize detritus from fields enters waterways after harvest, Cry1Ab proteins can also leach into adjacent streams, but the environmental fate of Cry1Ab is not well-studied. To fill this gap, we conducted monthly (June-November) short-term additions of leached Cry1Ab in four 50m experimental streams to estimate Cry1Ab transport and retention. At the onset of our experiments when rocks were bare, we found no evidence of Cry1Ab uptake, but retention steadily increased with benthic biofilm colonization. Overall, Cry1Ab uptake was predicted by epilithon chlorophyll a and filamentous algal cover. Average Cry1Ab removal, expressed as an uptake velocity (vf = 0.059 0.009 mm/s) was comparable to previously reported uptake of labile dissolved organic carbon (mean vf = 0.04 0.008 mm/s). Although Cry1Ab rapidly degrades in stream water, biofilms colonizing inorganic and organic surfaces may influence the distance proteins are transported in lotic systems, making Cry1Ab detection dependent on the ecological context of the stream ecosystems where it is released.

Arial Shogren (Primary Presenter/Author), University of Alabama, ashogren@ua.edu;
Assistant Professor, Department of Biological Sciences, University of Alabama

Jennifer L. Tank (Co-Presenter/Co-Author), University of Notre Dame, tank.1@nd.edu;


Martha M. Dee (Co-Presenter/Co-Author), University of Notre Dame, mdee@nd.edu;


Shannon Speir (Co-Presenter/Co-Author), University of Arkansas, slspeir@uark.edu;


Emma Rosi (Co-Presenter/Co-Author), Cary Institute of Ecosystem Studies, rosie@caryinstitute.org;


Scott Egan (Co-Presenter/Co-Author), scott.p.egan@rice.edu , Rice University;


Diogo Bolster (Co-Presenter/Co-Author), University of Notre Dame, diogo.bolster.5@nd.edu;


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5/24/2018  |   14:30 - 14:45   |  330 A

ANTHROPOGENIC LITTER IN URBAN STREAMS: SPATIAL DISTRIBUTION OF PLASTIC AND ITS ROLE IN LEAF LITTER BREAKDOWN Rivers are a major source of plastic litter to oceans, but the distribution of plastic and its effects on ecological processes within streams are rarely studied. Research suggests plastic litter (bags, wrappers) is trapped in addition to leaf litter within naturally occurring debris dams and riparian vegetation. In temperate, forested streams, debris dams are critical habitats and sites of leaf breakdown. We measured spatial distribution of anthropogenic litter within debris dam and non-debris dam habitats in urban streams in Chicago and Baltimore, USA. We measured leaf breakdown rates, biofilm communities, and macroinvertebrate communities in litterbags containing leaves alone, plastic alone, and mixed plastic and leaves in 3 urban streams for 4-5 months. Plastic density was significantly higher in debris dams, including overhanging riparian vegetation, than non-debris dam habitats. Plastic did not reduce leaf breakdown rates or affect macroinvertebrates, but plastic-only incubations had fewer invertebrates. Ongoing work will assess plastic's effect on biofilm communities. Plastic is abundant in debris dams, with variable effects on stream communities and ecosystem processes. More studies are needed to quantify plastic dynamics in stream ecosystems, and contribute to global models of plastic ecology.

Samuel Dunn (Co-Presenter/Co-Author), Loyola University Chicago , sdunn3@luc.edu;


Timothy Hoellein (Co-Presenter/Co-Author), Loyola University Chicago, thoellein@luc.edu;
Dr. Hoellein is a freshwater ecologist at Loyola University Chicago. His research interests are focused on ecosystem processes and biogeochemistry. His research lab explores these areas in associate with the movement and biological transformation of elements, energy, and pollution in aquatic ecosystems.

Lisa Kim (Primary Presenter/Author), Loyola University Chicago, lisahaneulkim@gmail.com;


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5/24/2018  |   14:45 - 15:00   |  

MERCURY BIOMAGNIFICATION IN AQUATIC FOOD WEBS ON A GLOBAL SCALE Methylmercury (MeHg) concentrations in aquatic food webs increase with trophic level (TL) but this process of biomagnification varies among systems. Herein we compared this process across gradients of latitude, physicochemical characteristics, and diversity using trophic magnification factors (TMFs), a metric based on the slope between log MeHg (or total Hg) concentrations and TL (measured with stable nitrogen isotopes; delta15N) that quantifies the per TL accumulation of this metal. In this global meta-analysis, TMF values were higher for MeHg (mean: 7.5 times/TL; range: 2–64) than for total Hg (mean: 4.8 times/TL; range: 0.2–91) across diverse freshwater and marine food webs. Some of this wide variation was related to latitude, with Arctic food webs having higher MeHg TMFs (~10 times/TL) than those from the tropics (~4 times/TL), likely because of slower growth rates in colder climates. In freshwater systems, MeHg TMF values were higher in riverine food webs compared to lacustrine ones. Understanding how Hg behavior in food webs is affected by system characteristics can help identify areas at greatest risk from legacy inputs or those that may respond more quickly to global reductions in Hg emissions through the Minamata Convention.

Karen Kidd (Primary Presenter/Author), McMaster University, karenkidd@mcmaster.ca;


Raphael Lavoie (Co-Presenter/Co-Author), University of Montreal, raphael.lavoie.3@umontreal.ca ;


Marc Amyot (Co-Presenter/Co-Author), University of Montreal, m.amyot@umontreal.ca;


Linda Campbell (Co-Presenter/Co-Author), Saint Mary's University, LM.Campbell@smu.ca;


Matthew Chumchal (Co-Presenter/Co-Author), Texas Christian University, m.m.chumchal@tcu.edu;


Tim Jardine (Co-Presenter/Co-Author), University of Saskatchewan, tim.jardine@usask.ca;


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5/24/2018  |   15:00 - 15:15   |  

MESOCOSM EXPERIMENTS CONDUCTED WITH METAL MIXTURES OFTEN REVEAL ECOLOGICAL SURPRISES Predicting fate and effects of chemical mixtures on aquatic organisms is complicated by our relatively poor understanding of contaminant interactions and our inability to quantify effects on ecologically meaningful endpoints. Mesocosm experiments using natural communities provide an opportunity to assess these direct and interactive effects. Over the past 25 years we have focused much of our research on assessing responses of benthic communities to metal mixtures associated with historical mining activities. Because these mixtures often include metals that cause both toxicological (Cd, Cu and Zn) and physical (Fe hydroxide deposition) effects, mesocosm experiments were necessary to quantify responses. We conducted a meta-analysis of 30 mesocosm experiments conducted with macroinvertebrate communities collected from 8 different streams to quantify the effects of metal combination, community source and season on responses to metal mixtures. Depending on the specific metal combination, results showed both synergistic and antagonistic effects. Sensitivity of macroinvertebrate communities to metals also varied among seasons and was influenced by community source, demonstrating the context-dependent nature of these responses. These results could help explain the vast discrepancies between laboratory and field responses to metals often reported in the literature.

William Clements (Primary Presenter/Author), Colorado State University, william.clements@colostate.edu;


Christopher Kotalik (Co-Presenter/Co-Author), United States Geological Survey, ckotalik@usgs.gov;


Brian Wolff (Co-Presenter/Co-Author), Colorado State University, wolffba@gmail.com;


Pete Cadmus (Co-Presenter/Co-Author), Colorado Parks and Wildlife, pete.cadmus@state.co.us;


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