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SFS Annual Meeting

2021 Detailed Schedule

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GLYPHOSATE EXPOSURE IMPACTS ON BENTHIC SEDIMENT MICROBIAL COMMUNITIES: A MICROCOSM EXPERIMENT IN THE NORTHERN GREAT PLAINS [Oral Presentation]

Peter Bergholz (Co-Presenter/Co-Author)
North Dakota State University, peter.bergholz@ndus.edu;

Kaycie Schmidt (Co-Presenter/Co-Author)
North Dakota State University, kaycie.schmidt@ndsu.edu;

Jon Sweetman (Co-Presenter/Co-Author)
Environmental and Conservation Sciences Program and Department of Biological Sciences, North Dakota State University, sweetman.jon@ndsu.edu;

Christine Cornish (Primary Presenter/Author)
North Dakota State University, christine.cornish@ndsu.edu;

Abstract: Increasing herbicide use frequently leads to contamination of aquatic ecosystems via spray drift, runoff, or groundwater transport. Glyphosate is the most commonly used herbicide worldwide and is widely distributed in wetland waters and sediments. Wetland sediments often serve as sinks where glyphosate and its metabolite aminomethylphosphonic acid (AMPA) can accumulate, leaving the benthic microbiome vulnerable to direct or indirect effects. Research suggests that exposure to glyphosate causes shifts in community composition or function by either inhibiting species growth and reproduction, or enhancing microbial communities by providing a novel phosphorus, nitrogen, and carbon source. We conducted a replicated microcosm experiment to assess how benthic sediment microbiomes respond to exposure of glyphosate, AMPA, or a glyphosate-based formula. Sediments were collected from a wetland with no immediate adjacent agricultural activity. Additionally, no glyphosate or AMPA residues were detected prior to the start of the experiment. Herbicides were added at 0.07, 0.7, or 7 ppm and sediment was collected pre-treatment, two hours post-treatment, and two weeks post-treatment for herbicide and microbial analyses. Preliminary results show no significant differences in microbial community composition between treatments, which could suggest an adapted resistance to the ubiquitous compound.

Host specificity and condition-dependency of chytrid infection of Scenedesmus spp. [Oral Presentation]

Ty Samo (Co-Presenter/Co-Author)
Lawrence Livermore National Laboratory, samo1@llnl.gov;

Christopher Ward (Co-Presenter/Co-Author)
Bowling Green State University, chrward@bgsu.edu;

Fiona Harrigian (Primary Presenter/Author)
Bowling Green State University, fharrig@bgsu.edu;

Abstract: Chytrid fungi are cryptic yet critical members of aquatic ecosystems. In both natural and engineered environments, parasitic chytrids can reduce green algal populations, sometimes through sudden crashes. Despite this common occurrence, how chytrid infectivity is influenced by algal host identity and environmental factors is poorly understood. In our study, we explored these questions in laboratory experiments using an obligate aphelid and numerous green algal strains with a particular focus on Scenedesmus spp. The aphelid was found to be capable of infecting several algal strains, including Scenedesmus obliquus UTEX 393 and Scenedesmus dimorphus UTEX 1237, though infection prevalence was highest for S. obliquus. Lower light levels reduced infection in the S. dimorphus culture but did not significantly affect infection in the S. obliquus culture. Infection increased in both Scenedesmus strains at 30°C compared to 25°C. Continuing work will explore additional environmental factors and their interactions with one another. These findings contribute greater insight into how chytrid infection governs algal abundance, diversity and productivity in aquatic ecosystems.

Multiple trophic strategies employed by chytrids interacting with algae suggest multifarious ecosystem roles [Oral Presentation]

Michael Thelen (Co-Presenter/Co-Author)
Lawrence Livermore National Laboratory, thelen1@llnl.gov;

Rhona Stuart (Co-Presenter/Co-Author)
Lawrence Livermore National Laboratory, stuart25@llnl.gov;

Christopher Ward (Primary Presenter/Author)
Bowling Green State University, chrward@bgsu.edu;

Abstract: Chytrids are key regulators of primary production and carbon cycling in aquatic ecosystems. Despite chytrid crashes of microalgal populations, the ecology of alga-chytrid interactions remains unresolved. To investigate drivers of chytrid infection, we isolated two fungal strains Rhizophydium sp. and Paraphysoderma sedebokerense that infect Haematococcus pluvialis. Culture-based assays indicated fungal infectivity’s dependence on temperature and algal growth stage. Further, we discovered that these fungal strains possess a noninfective lifestyle in which they feed on algal spent media or certain components of algal exudate. In culture, the chytrid’s trophic strategy appears to be regulated by organic carbon availability. Quantitative PCR of chytrid groups validated that the noninfective lifestyle is a critical component of fungal dynamics in algal-dominated systems. Genomic analysis of P. sedebokerense identified features that may underlie its trophic versatility. Ongoing work aims to resolve the mechanistic underpinnings of chytrid metabolisms, observe algal-chytrid interactions in situ and introduce new algal-associated chytrid models. Identifying the molecular mechanisms and ecological drivers controlling chytrid metabolism is critical for deciphering their complex environmental roles, and will ultimately benefit our understanding of algal production and aquatic carbon cycling.

OXYGEN, PH, AND LABILE ORGANIC CARBON AS POSSIBLE MECHANISMS FOR ALGAL STIMULATION OF BACTERIAL AND FUNGAL PRODUCTION IN PERIPHYTON [Oral Presentation]

Jennifer Harper (Primary Presenter/Author)
Biology Department, Eastern Michigan University, jharpe18@emich.edu;

Kevin Kuehn (Co-Presenter/Co-Author)
The University of Southern Mississippi, kevin.kuehn@usm.edu;

Halvor Halvorson (Co-Presenter/Co-Author)
University of Central Arkansas, hhalvorson@uca.edu;

Robert Findlay (Co-Presenter/Co-Author)
University of Alabama, rfindlay@ua.edu;

Steven Francoeur (Co-Presenter/Co-Author)
Eastern Michigan University, sfrancoeu@emich.edu;

Abstract: Recent research indicates that algal photosynthesis is stimulatory to microbial heterotrophs within periphyton communities, however the exact mechanisms driving this stimulation remain unknown. We incubated submerged Typha domingensis leaf litter in greenhouse mesocosms under low and high nutrient regimes and conducted microbial production assays after 11 or 18 weeks of colonization. We manipulated environmental factors (oxygen, pH, and labile organic carbon) affected by algal photosynthesis to test the hypothesis that one or more of these factors stimulated heterotrophic microbial production. In the low nutrient treatments, bacterial production was increased by glucose addition during week 11 (p<0.001) and by photosynthesis during week 18 (p<0.05). Fungal production was stimulated by photosynthesis in the high nutrient treatments during weeks 11 (p<0.001) and 18 (p<0.01) and by glucose during week 11 (p<0.05). Our results confirm that algal photosynthesis can increase heterotrophic microbial production and suggest that photosynthetic labile organic carbon production could be an important stimulatory mechanism. The research highlights the role of photosynthesis as a stimulator of heterotrophic processes in aquatic ecosystems.

PATTERNS IN MICROBIAL COMMUNITIES IN A LARGE RIVER AND CONNECTED BACKWATER LAKES WITH VARIABLE HYDROLOGY [Oral Presentation]

John Marino (Primary Presenter/Author)
Bradley University, jmarino@fsmail.bradley.edu;

Alexandra Beanblossom (Co-Presenter/Co-Author)
Bradley University, abeanblossom@mail.bradley.edu ;

Abstract: Hydrology strongly influences aquatic ecosystems, with consequences for microbial communities and important processes (e.g., decomposition, phytoplankton productivity). The goal of our study was to examine variation in the microbial community across hydrologically variable systems. Water samples were collected on eight dates in Summer 2018 from four sites in central Illinois, including the Illinois River and three backwater lakes. Water levels at one site (Thompson Lake) were lowered via pumping during the season, allowing comparison of a site with modified hydrology to sites linked more to river hydrology. Water samples were filtered and DNA extracted for 3 size fractions (>20 micron, 3-20 micron, and 0.22-3 micron). Sequencing data targeting different taxa (16S for bacteria, ITS for fungi) were generated using Illumina MiSeq. We found that microbial diversity and composition varied among sites (p < 0.05) and size fractions (p < 0.001), while not over time (p > 0.05). Differences among sites may arise from hydrological and other environmental factors, while differences among fractions suggest communities of particulate-associated microbes differ from free-living. Our findings offer new insights into variation in these microbial communities, with implications for ecosystem functioning and water quality.

THE EFFECT OF FRESHWATER MUSSELS ON SEDIMENT MICROBIAL COMMUNITIES UNDER DIFFERENT NUTRIENT REGIMES [Oral Presentation]

Thomas Parr (Co-Presenter/Co-Author)
U.S. National Park Service, thomas.parr@ou.edu;

Caryn Vaughn (Co-Presenter/Co-Author)
University of Oklahoma, cvaughn@ou.edu;

Edward Higgins (Primary Presenter/Author)
University of Oklahoma, higginse@ou.edu;

Abstract: Freshwater mussels are sedentary, burrowing filter feeders. Aggregates of mussels (mussel beds) have significant impacts on nutrient cycling in rivers through biofiltration and excretion and biodeposition of wastes. Mussels burrow at the sediment oxic-anoxic interface and alter the distribution of microbial taxa associated with nitrogen cycling, including the ecologically relevant nitrogen transformation, ANAMMOX. Mussels species also have different thermal and behavioral traits that affect their impact on nutrient cycling. Actinonaias ligamentina is an active, thermally sensitive species with stronger effects on nutrient cycling than Amblema plicata, a more sedentary, thermally tolerant species. We hypothesized that these trait differences between species would impact the sediment microbial community’s structure and function, depending on background nutrient availability. To test this, we conducted a mesocosm experiment with treatments of each species where we manipulated N and P concentrations and tracked changes in sediment bacterial communities using 16s rRNA barcode gene and sediment bacterial function using fluorometric enzyme analyses. Sample processing and analysis was delayed because of the pandemic but will be complete prior to the SFS meeting. Our results should expand our understanding of the relationship between animals, bacterial communities, and ecosystem function.

WATERSHED ROW-CROP AGRICULTURE DOES NOT CORRELATE WITH MICROBIAL NITROGEN-CYCLING GENETIC POTENTIAL ACROSS A GRADIENT OF EASTERN KANSAS STREAMS [Oral Presentation]

Janaye Hanschu (Co-Presenter/Co-Author)
Kansas State University, jhanschu@ksu.edu;

Abagael Pruitt (Co-Presenter/Co-Author)
University of Notre Dame, apruitt2@nd.edu;

Samantha Thomas (Co-Presenter/Co-Author)
Kansas Biological Survey, University of Kansas, Lawrence, KS, sgthomas@ku.edu;

Matthew VanderPutten (Co-Presenter/Co-Author)
Kansas State University, matthe76@ksu.edu;

Amy Burgin (Co-Presenter/Co-Author)
University of Kansas, burginam@ku.edu;

Matthew Kirk (Co-Presenter/Co-Author)
Kansas State University, mfkirk@ksu.edu;

Lydia Zeglin (Co-Presenter/Co-Author)
Kansas State University, lzeglin@ksu.edu;

Joshua Dimapilis (Primary Presenter/Author)
Kansas State University, joshuard@ksu.edu;

Abstract: Widespread conversion of grassland to row-crop agriculture has caused increased fertilizer-derived nitrate runoff to many streams, and higher nitrous oxide production. Bacteria and archaea mediate nitrogen (N) cycling; yet, little is known about their distribution in streams. This study assesses relationships between agricultural density, microbial N-cycling functional group abundance, and microbial diversity in water and benthic sediment at 69 sites across a land-use gradient. We hypothesized that microbiota from sites with more row-crop agriculture upstream would have greater N-cycling potential, indicated by higher 16S bacterial rRNA, bacterial amoA (ammonia monooxygenase), and nosZ (nitrous oxide reductase) clade I gene copies, and distinct microbial community composition. We ran quantitative PCR of target genes, and sequenced 16S rRNA gene libraries, on DNA extracted from triplicate samples collected in 2018. Unexpectedly, land-use and N-cycling functional potential were not correlated. However, there was a positive correlation between nosZ and bacterial amoA gene copies, suggesting that products of nitrifier metabolism support denitrifier populations, and that a gradient of slow to fast N-cycling microbiomes exists independent of watershed land-use. Next, we will assess correlations between N-cycling potential and other factors, to learn what may drive this variability.

Whole-microbial community (Bacteria, Archaea and Eukarya) assembly across the river continuum [Oral Presentation]

Lydia Zeglin (Primary Presenter/Author)
Kansas State University, lzeglin@ksu.edu;

Amy Burgin (Co-Presenter/Co-Author)
University of Kansas, burginam@ku.edu;

Kyle Cochran (Co-Presenter/Co-Author)
Kansas State University, kylecochran@ksu.edu;

Janaye Hanschu (Co-Presenter/Co-Author)
University of Kansas, janayeh@ku.edu;

Yasawantha Hiripitiyage (Co-Presenter/Co-Author)
University of Kansas, devindahiri@ku.edu;

Matthew Kirk (Co-Presenter/Co-Author)
Kansas State University, mfkirk@ksu.edu;

Brett Nave (Co-Presenter/Co-Author)
Kansas State University, bnave@ksu.edu;

Emma Overstreet (Co-Presenter/Co-Author)
Kansas Biological Survey, University of Kansas, Lawrence, KS, evover@live.com;

Belinda Sturm (Co-Presenter/Co-Author)
University of Kansas, bmcswain@ku.edu;

Samantha Thomas (Co-Presenter/Co-Author)
Kansas Biological Survey, University of Kansas, Lawrence, KS, sgthomas@ku.edu;

Matthew VanderPutten (Co-Presenter/Co-Author)
Kansas State University, matthe76@ksu.edu;

Abstract: Many environmental factors shift as water moves through a stream network, with consequences for biotic assembly. The River Continuum Concept (RCC) suggests that the quantity and quality of the energy source for most biota drives community assembly through different stream orders; in contrast, recent work shows that residence time of water in the network affects bacterial community assembly. This study evaluates whether community change in assemblages of different microbial groups through networks (stream orders 2-8) supports each hypothesis, with the prediction that archaeal, bacterial and eukaryal protistan heterotrophs will follow the residence time hypothesis, and photoautotrophic cyanobacteria and algae will follow the RCC. Stream order explains community variation in all groups, most strongly for bacterial and archaeal heterotrophs, followed by cyanobacteria, then algae, then protists (respectively, PERMANOVA: R2 = 19.8%, 13.6%, 11.1%, 10.4%; all p<0.001). Photoautotroph communities follow a RCC-like threshold pattern, with clearest shifts between stream orders 5 and 6; bacteria follow more of a gradient, supporting the residence time hypothesis; but protists fit neither model. Protists might not disperse from a terrestrial source, like bacteria, or as generalist grazers they might be insensitive to basal energy source.

BIOFILMS ON PLASTIC LITTER IN AN URBAN RIVER: COMMUNITY COMPOSITOIN AND FUNCTION [Poster Presentation]

Raul Lazcano (Primary Presenter/Author)
Loyola University Chicago, rlazcanogonzalez@luc.edu;

Abstract: Plastic litter is a common pollutant worldwide. In aquatic ecosystems, plastic litter is a substrate for biofilms, but little research has compared the activity and composition of biofilms which colonize buoyant plastic litter in rivers to those colonizing a natural substrate: woody debris. We will incubate three common plastics of distinct textures, low-density polyethylene (firm), low-density polyethylene film (flexible), and foamed polystyrene (brittle), and wood (untreated veneer) in the Chicago River for six weeks. Substrates will be incubated just below the water surface with even distribution and depth and removed weekly. In the lab, we will measure biofilm respiration, flux of nitrogen gas and nitrate, chlorophyll, and biomass. DNA will be extracted for microbial community analysis using next-generation sequencing. We predict biofilm activity and composition on plastics will be distinct from one another and from those on wood, especially in the first weeks of incubation, and plastic biofilms will be less diverse than those on wood. This study will provide valuable insights into the effects of substrate on biofilm characteristics, as well as the ecological impacts of plastic pollution on urban rivers.

LOCAL STRESSORS MINIMIZE THE EFFECTS OF NUTRIENTS ACROSS WATERSHEDS OF DIFFERENT SIZES AND DEGREES OF CHEMICAL IMPAIRMENT [Poster Presentation]

Emily Huff (Primary Presenter/Author)
West Liberty University, ethuff@westliberty.edu;

James Wood (Co-Presenter/Co-Author)
West Liberty University, James.Wood@westliberty.edu;

Abstract: Microbial carbon processing in streams can be affected by nutrient enrichment and exposure to toxic chemicals, but there is a need to better understand the nature of these effects across a variety of watershed sizes. At 13 sites in the upper Ohio River watershed, we investigated the effects of water chemistry on microbial processing using two types of standardized carbon substrates to test the hypothesis that chemical stressors can override the stimulatory effects of nutrients on microbial processing rates. We assessed microbial respiration and breakdown rates using a labile cellulose sponge, and a recalcitrant red oak wood veneers after four or six weeks, respectively across a range of watershed sizes. Labile carbon substrate respiration rate was positively correlated with chloride and SRP while negatively correlated with nitrate; breakdown rate was weakly positively correlated with SRP and temperature. On the wood substrates, respiration was negatively correlated with nitrate and weakly negatively correlated with DIN; breakdown was similarly only weakly negatively correlated with DIN. Our results indicate that differences that local stressors and in-stream conditions can exert strong effects on microbial processing potentially overshadowing the effects of nutrient stimulation.

MICROBIAL COLONIZATION OF MICROPLASTIC FIBERS IS ALTERED BY ADSORPTION OF AN ANTIMICROBIAL COMPOUND [Poster Presentation]

Justine Nguyen (Co-Presenter/Co-Author)
Loyola University Chicago, justinenguyen6402@gmail.com;

Kathryn Renyer (Co-Presenter/Co-Author)
Loyola University Chicago, krenyer@luc.edu;

Paul Chiarelli (Co-Presenter/Co-Author)
Loyola University Chicago, mchiare@luc.edu;

Timothy Hoellein (Co-Presenter/Co-Author)
Loyola University Chicago, thoellein@luc.edu;

John Kelly (Co-Presenter/Co-Author)
Loyola University Chicago, Jkelly7@luc.edu;

Karl Gaisser (Primary Presenter/Author)
Loyola University Chicago, kgaisser@luc.edu;

Abstract: Microplastics and pharmaceuticals are common contaminants in domestic wastewater that can enter freshwater ecosystems via treated or untreated wastewater. Within freshwaters, microplastics are colonized by microorganisms and can adsorb other contaminants, including pharmaceuticals, creating hot-spots for microbe-pharmaceutical interactions. Triclosan is an antimicrobial compound found in personal care products that is present in the water, sediment, and on plastic litter in urban rivers. Interactions between microplastics, triclosan, and microbes in urban rivers are likely, but have not yet been measured. We incubated acrylic, nylon, and polyester fibers with or without adsorbed triclosan in water collected from the Chicago River for 30 days. DNA-based analysis of microbial assemblages attached to the fibers and in the water indicated that triclosan lowered diversity and shifted microbial assemblage composition both on the microplastic surface and in the water. Differential abundance analysis showed that several bacterial phyla were more abundant in the triclosan treatments, including cyanobacteria and proteobacteria. Interactions between microplastics and pharmaceuticals within freshwater habitats may impact microbes and microbially mediated processes, and merit more research attention.

PHYLOGENETIC ANALYSIS OF PHAGE COMMUNITY DIVERSITY USIGN PHOH AND THYMIDYLATE SYNTHASE AS SIGNATURE GENES [Poster Presentation]

Ana Cruz (Primary Presenter/Author)
Rowan University, cruzan26@students.rowan.edu;

Alisha Vincent (Co-Presenter/Co-Author)
Rowan University, vincen86@students.rowan.edu;

Abstract: Bacteriophages are key regulators of microbial communities. Because Caulobacter crescentus is a common freshwater bacterium, we compared genomic sequences of novel caulophage from New Jersey lakes to each other and to previously described caulophages. We determined that all of our New Jersey phages are Phicbkviruses, a previously described group. Caulophage community diversity was characterized by analyzing phoH and thymidylate synthase (TSase) as signature genes. For both genes, the predicted phage amino acid sequences were distinct from the host sequences. In the TSase phylogenetic tree, the phages associated into six distinct clusters. Some New Jersey phages fell into a known Phicbkvirus clade containing phage isolated from Texas and South Carolina, but the others distributed into two novel clusters distinct from known Phicbkviruses. The phoH tree was similar to that of TSase. However, in phage BL10 the gene is more similar to phoH from C. crescentus than to any of the phage sequences. The most recent common ancestor of all six Phicbkvirus clades likely carried phoH and TSase genes originating from an organism other than Caulobacter, and presumably BL10 replaced its phoH gene via a horizontal transfer event involving the Caulobacter host.

THE RELATION OF MICROBIAL BIOMASS CARBON WITH DENITRIFICATION AND NUTRIENT RETENTION IN RESTORED FLOODPLAIN WETLANDS [Poster Presentation]

Shrijana Duwadi (Primary Presenter/Author)
Tennessee Tech University, sduwadi42@tntech.edu;

Spencer Womble (Co-Presenter/Co-Author)
Tennessee Tech University, sgwomble42@tntech.edu;

Robert Brown (Co-Presenter/Co-Author)
Tennessee Tech University, rsbrown43@tntech.edu;

Justin Murdock (Co-Presenter/Co-Author)
Tennessee Tech University, jnmurdock@tntech.edu;

Abstract: Restoration activities have been implemented in the lower Mississippi River basin through the Wetlands Reserve Program (WRP) to enhance essential functions by restoring wetlands. Soil can be a zone of significant nutrient retention in wetlands by providing an environment for microbial development and nutrient processing. The objective of this study was to assess soil microbe-based ecosystem function in three restored riparian wetlands in Western Kentucky, focusing on the relationship between microbial biomass and nutrient removal. We hypothesized that nutrient retention, and specifically denitrification is directly related to microbial biomass carbon (MBC). At each easement, thirty sediment cores were collected and used to measure a suite of soil processes and properties, including soil nitrogen (N) and phosphorus (P) uptake rates, denitrification potential, soil moisture, and MBC. MBC was significantly higher in undisturbed older habitat, followed by remnant forest, and lowest in the shallow water areas. Denitrification potential, and N and P uptake were strongly correlated with MBC and soil moisture. Our results suggest that increasing total soil microorganism biomass is an indicator for monitoring improvements in ecological functions in restored wetlands, with potentially important long-term consequences for denitrification and nutrient retention.