SFS Annual Meeting

5/21/2019  |   14:00 - 14:15   |  150 G

SPATIOTEMPORAL MICROBIOME ASSEMBLY AND METABOLISM IN HYDROLOGICALLY-CONNECTED MICROBIOMES Subsurface groundwater-surface water mixing zones (hyporheic zones) have enhanced microbial metabolism, but assembly processes governing hyporheic microbiome composition remain poorly understood. Here, we investigated (a) biogeographical patterns in attached and waterborne microbiomes in three hydrologically-connected areas; (b) assembly processes that generated these patterns; and (c) spatiotemporal relationships between assembly processes and microbial metabolism. All microbiomes remained dissimilar through time, and we demonstrated a pronounced impact of deterministic assembly in all microbiomes. Additionally, we show seasonal shifts from heterotrophy to autotrophy associated with increases in groundwater discharge. The abundance of one cluster of organisms increased with active biomass and respiration, revealing organisms that may strongly influence hyporheic biogeochemistry. Finally, we demonstrate that multiple selective pressures—imposed by sediment and porewater physicochemistry—integrate to generate changes in microbiome composition at distinct timescales among habitat types. Based on our results, we present a conceptual model in which metabolism increases when oscillating (hydrologic) selective pressures oppose stable (sediment) selection; and in which organic carbon concentrations during surface water intrusion supports heterotrophic metabolism. Our research provides new opportunities to enhance microbially-explicit ecosystem models describing hyporheic zone biogeochemistry and its influence over riverine ecosystem function.

Emily Graham (Primary Presenter/Author), Pacific Northwest National Laboratory, emily.graham@pnnl.gov;


Alex Crump (Co-Presenter/Co-Author), University of Idaho, acrump@uidaho.edu;


C. Tom Resch (Co-Presenter/Co-Author), Pacific Northwest National Laboratory, tom.resch@pnnl.gov;


Sarah Fansler (Co-Presenter/Co-Author), Pacific Northwest National Laboratory, sarah.fansler@pnnl.gov;


Evan Arntzen (Co-Presenter/Co-Author), Pacific Northwest National Laboratory, evan.arntzen@pnnl.gov;


James Stegen (Co-Presenter/Co-Author), Pacific Northwest National Laboratory, james.stegen@pnnl.gov;


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5/21/2019  |   14:15 - 14:30   |  150 G

THE MICROBIOME OF STREAM MACROINVERTEBRATES: CONNECTING COMMUNITY COMPOSITION TO ECOSYSTEM FUNCTION Stream microorganisms perform critical biogeochemical functions including denitrification (an important process that removes bioavailable N). Likewise, macroinvertebrates are ecologically important and potentially represent a novel habitat for microorganisms. We demonstrated that stream macroinvertebrates have a diverse microbiome and that composition and diversity vary among hosts. Macroinvertebrate functional feeding groups and stream (anthropogenically impacted versus unimpacted) determined gut bacterial diversity; 79 phylotypes differed significantly among macroinvertebrate types. These microbiomes include microorganisms that have functional genes capable of performing a variety of aspects of the N cycle, including denitrification. Capabilities of the macroinvertebrate microbiome were put in context by comparing denitrification rates among macroinvertebrates and sediment and water from a fourth order stream (OH, USA). Macroinvertebrates sampled sufficiently were from the families Cambaridae, Athericidae, Baetiscidae, and Hydropsychidae. Denitrification rates were about 4 times higher in macroinvertebrates than in sediments. Denitrification rates ranged from 0.27µLN2O-N g wet weight (Athericidae) to 2.24µLN2O-N g wet weight (Cambaridae) and differed among families. Ongoing work will relate functional genes (narG, nirS, and nosZ ) to denitrification rates. In conclusion, stream macroinvertebrates harbor diverse communities that differ among taxa and appear to be important to ecosystem processes.

Sohini Bhattacharyya (Primary Presenter/Author), Kent State University, sbhatta6@kent.edu;


Paul Ayayee (Co-Presenter/Co-Author), University of Nebraska at Omaha, payayee@unomaha.edu;


Laura Leff (Co-Presenter/Co-Author), Kent State University, lleff@kent.edu;


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5/21/2019  |   14:30 - 14:45   |  150 G

FRESHWATER MUSSELS INFLUENCE SEDIMENT MICROBIAL COMMUNITY COMPOSITION AND FUNCTION Bacteria play critical roles in nutrient cycling, changing biologically unavailable nutrients into accessible forms which supports primary production. Interactions between microbiomes, the multicellular organisms that host them, and the environment are understudied, especially in freshwater systems. Because geographic isolation has less impact on microbial community structure than habitat type, ecosystem engineers should have large influences on microbiome composition. Thus, freshwater mussels (Unionoida) are a good study system to investigate animal-microbiome interactions as they link multiple microhabitats together, such as the water column and sediment (through filter feeding) as well as aerobic and anaerobic sediments (through burrowing). To investigate linkages between mussels and microbiome composition, we collected sediment and mussel fecal, shell, and gut samples from the Kiamichi River, Oklahoma in August 2017 and July 2018. We used the 16s rRNA gene as a genetic barcode for community analysis. From our 2017 samples, we found that there are no species-specific differences between fecal samples. However, PERMANOVA shows sediments cluster based on proximity to different species as well as non-mussel, upstream samples. Additionally, mussels significantly alter the number of key nutrient cycling species potentially impacting overall microbiome function.

Thomas Parr (Co-Presenter/Co-Author), University of Oklahoma, 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;


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5/21/2019  |   14:45 - 15:00   |  150 G

BIOGEOGRAPHY OF BACTERIA IN HEADWATER STREAMS ACROSS BIOMES AND SEASONS Benthic microbial communities of headwater streams conduct important processes for maintaining critical stream ecosystem functions both within headwaters and downstream. Not all headwater communities are equal and there is a growing effort to understand which factors are responsible for differences among them and more generally to understand the utility and limitations of bacterial biogeography information. Using three well-studied catchments, White Clay Creek (PA, USA), Neversink River (NY, USA) and Rio Tempisquito (Costa Rica), we examined the influence of catchment, season, substrate type (rock vs. sediment), stream order, and water chemistry on the composition of streambed microbial communities characterized by 16S rRNA genes. The direction and magnitude of change in bacterial richness between stream orders depended on catchment, substrate, and season. Partial redundancy analysis showed that substrate type (8.1%) was more influential than catchment (4.6%), season (1.8%), and stream order (1.5%) in structuring bacterial community composition. Relative abundance of Cyanobacteria was seven times greater in rock biofilms than sediments, while Acidobacteria had twice the relative abundance in sediments compared with rock biofilms. Our results suggest that changes in benthic substrate could substantially alter the biogeography of bacteria in headwater streams, globally.

Raven Bier (Primary Presenter/Author), University of Georgia, rbier@srel.uga.edu;


Jinjun Kan (Co-Presenter/Co-Author), Stroud Water Research Center, jkan@stroudcenter.org;


Jennifer Mosher (Co-Presenter/Co-Author), Marshall University, mosher@marshall.edu;


Louis Kaplan (Co-Presenter/Co-Author), Stroud Water Research Center, lakaplan@stroudcenter.org;


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5/21/2019  |   15:00 - 15:15   |  150 G

WIDESPREAD CRYPTIC VIRAL INFECTIONS IN BENTHIC BIOFILM COMMUNITIES As the most ubiquitous biological entities on earth, viruses have important impacts on aquatic microbial ecology and have been studied at length in the global ocean. However, the role of bacteriophage in lotic ecosystems, particularly in benthic biofilms, has gone largely unstudied. We hypothesized that temperate bacteriophage can circumvent the protective cuticle covering most biofilms through integration into bacterial genomes. Furthermore, prophage induction may play an important role in the biofilm lifecycle. To investigate the potential importance of lysogeny in benthic biofilms, prophage induction experiments were carried out on samples of both naturally occurring and laboratory grown freshwater benthic biofilms. Both field and laboratory experiments revealed evidence of prophage induction in nearly all samples. Our results suggest that bacteriophage can infect freshwater biofilms through lysogenic infection, with important implications for stream ecology.

Alexandra Payne (Co-Presenter/Co-Author), College of William and Mary, atpayne@email.wm.edu;


Kurt Williamson (Primary Presenter/Author), College of William and Mary, kewilliamson@wm.edu;


Abigail Davidson (Co-Presenter/Co-Author), College of William and Mary, ajdavidson@email.wm.edu;


Jinjun Kan (Co-Presenter/Co-Author), Stroud Water Research Center, jkan@stroudcenter.org;


Raven Bier (Co-Presenter/Co-Author), Stroud Water Research Center, rbier@stroudcenter.org;


Jing Wang (Co-Presenter/Co-Author), Stroud Water Research Center, jwang_hku@163.com;


Marc Peipoch (Co-Presenter/Co-Author), Stroud Water Research Center, mpeipoch@stroudcenter.org;


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5/21/2019  |   15:15 - 15:30   |  150 G

A TALE OF TWO TAXONOMIES: COMPARING MORPHO- AND MOLECULAR TAXONOMY FOR STREAM ALGAL BIOASSESSMENT DNA metabarcoding provides a rapid and scalable alternative to traditional morpho-taxonomic approaches for generating taxonomic data for stream algal bioassessment. However, protocols for the generation and analysis of DNA data are not yet standardized and analytical pipeline choices can bias resulting species data and therefore site bioassessment scores. In an effort to optimize the generation of DNA-based taxonomic data for stream bioassessment, we performed metabarcode sequencing (16S/18S rRNA genes) on 80 algae samples from California wadeable streams. We compared molecular taxonomies to paired morpho-taxonomic data for diatoms and soft-algae and calculated California algal index scores (ASCI) for each site. Additionally, we compared bacteria and archaea communities to algal index scores to identify prokaryote taxa associated with biointegrity and stressor gradients across sites. We found a clear influence of DNA barcode region on resulting biological index scores. DNA-based index scores were consistent across bioinformatic treatments, although on average lower than morpho-taxonomic scores. Both molecular and morpho-taxonomic approaches omitted key taxa, although with DNA sequencing we identified potential novel indicator species for prokaryote-based indices. These results demonstrate potential of molecular methods to advance bioassessment while also highlighting the importance of methods standardization.

Susanna Theroux (Primary Presenter/Author), Southern California Coastal Water Research Project, susannat@sccwrp.org;


Joshua Steele (Co-Presenter/Co-Author), Southern California Coastal Water Research Project, joshuas@sccwrp.org;


John Griffith (Co-Presenter/Co-Author), Southern California Coastal Water Research Project, johng@sccwrp.org;


Eric Stein (Co-Presenter/Co-Author), Southern California Coastal Water Research Project, erics@sccwrp.org;


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