SFS Annual Meeting

6/03/2024  |   10:30 - 10:45   |  Freedom Ballroom H/G

MICROBIAL LEAF LITTER DECOMPOSITION IN TEMPERATE INTERMITTENT STREAMS In-stream decomposition of leaf litter is a major source of carbon and energy for intermittent headwater streams and a vital component of nutrient cycling in those systems. Microbial decomposition of leaf litter is dependent on environmental factors, litter diversity and the composition of the decomposer community, which in turn are affected by the high spatial heterogeneity of intermittent streams. We assessed the ability of the streambed leaf litter microbiome to decompose organic carbon and mineralize organic nitrogen and phosphorus in intermittent stream networks in Alabama and Idaho, USA. Leaf litter was collected from 50 locations in each of Pendergrass Creek (AL) and Gibson Jack Creek (ID), and the activity of microbial enzymes associated with decomposition (B-glucosidase, phenol oxidase, peroxidase) and the mineralization of phosphorus (phosphatase), and nitrogen (N-acetylglucosaminidase) were assayed. Leaf litter in Gibson Jack Creek (ID) showed higher enzyme activity compared to Pendergrass Creek (AL) (mean activity 7.0-72.0 umol/h/g DW and 5.4-37.9 umol/h/g DW, respectively). B-glucosidase was the most active enzyme on leaf litter in both systems and showed twice as much activity in Gibson Jack Creek than in Pendergrass Creek. Activities of N-acetylglucosaminidase and phenol oxidase were higher in Pendergrass Creek than Gibson Jack and were positively correlated with beech leaf species in Pendergrass Creek but negatively correlated with birch in Gibson Jack Creek. These results highlight the important role litter identity plays in determining the microbial decomposition of leaf litter in streams.

Andrielle L. Kemajou Tchamba (Primary Presenter/Author), University of Mississippi, akemajou@go.olemiss.edu;

Charles T. Bond (Co-Presenter/Co-Author), University of Southern Mississippi, Charles.Bond@usm.edu;

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

Claire Utzman (Co-Presenter/Co-Author), Kansas State University, crutzman@ksu.edu;

Robert Ramos (Co-Presenter/Co-Author), University of Kansas, rob.james.ramos@gmail.com;

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

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

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

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

Yaqi You (Co-Presenter/Co-Author), SUNY College of Environmental and Earth Sciences, yyou@esf.edu;

Ken Aho (Co-Presenter/Co-Author), Idaho State University, ahoken@isu.edu;

Carla L. Atkinson (Co-Presenter/Co-Author), University of Alabama, clatkinson@ua.edu;

Jerald Ibal (Co-Presenter/Co-Author), Idaho State University, jeraldibal@isu.edu;

Colin R. Jackson (Co-Presenter/Co-Author), University of Mississippi, cjackson@olemiss.edu;

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6/03/2024  |   10:45 - 11:00   |  Freedom Ballroom H/G

OXYGEN DEPLETION AND ANAEROBIC MICROBIAL RESPIRATION IN AN INTERMITTENT MEDITERRANEAN STREAM DURING TRANSITION FROM WET TO DRY CONDITIONS. Water scarcity induced by climate change can exacerbate stream anaerobic biogeochemical processes and associated greenhouse gas (GHG) emissions. However, our understanding of carbon and nitrogen cycling in headwater streams primarily relies on empirical studies conducted under aerobic conditions. Here, we investigated changes in aerobic metabolic rates, CO2 evasion, and potential GHG emissions following oxygen depletion in an intermittent Mediterranean stream during the transition from wet-to dry conditions. From April to June, we monitored dissolved oxygen and CO2 concentrations and measured potential GHG emissions and abundance of N cycling genes (using quantitative PCR) in different stream habitats. Stream CO2 concentration increased over time (2000 to 10000 ppmv), while oxygen showed the opposite pattern (15 to 0.1 mg L-1), suggesting an increase in anaerobic metabolic rates. Suboxic conditions (<5 mg L-1) occurred sporadically in April and became more frequent in June, with anoxia (<2 mg L-1) exceeding 5 h/day. Denitrification genes (nirK and nirS) represented 10-30% of nitrogen processing genes, with stable abundance over time. However, potential denitrification was highly variable (0.009 to 13.7 ng N-N2O g-1 h-1) and was positively related with stream nitrate concentrations, peaking after a small spring storm. This suggests riparian nitrogen inputs may control denitrification in this oligotrophic stream, especially in the late stage of stream desiccation when suboxic conditions favour anaerobic processes. Our results indicate high potential for anaerobic microbial respiration in this intermittent stream, which can contribute to GHG emissions, especially during periods of oxygen depletion and nutrient elevation.

Xavi Peñarroya (Primary Presenter/Author), Integrated Freshwater Ecology Group, Center for Advanced Studies of Blanes (CEAB-CSIC), Blanes, Girona, Spain., xp.galceran@gmail.com;

Sara Hallin (Co-Presenter/Co-Author), Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden, Sara.Hallin@slu.se;

Maria Hellman (Co-Presenter/Co-Author), Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden, Maria.Hellman@slu.se;

Carolina Jativa (Co-Presenter/Co-Author), Integrated Freshwater Ecology Group, Center for Advanced Studies of Blanes (CEAB-CSIC), Blanes, Girona, Spain., carito.jativa@gmail.com;

Emma Lannergård (Co-Presenter/Co-Author), Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden, emma.lannergard@slu.se;

Anna Lupon (Co-Presenter/Co-Author), Center for Advanced Studies of Blanes (CEAB-CSIC), Spain, alupon@ceab.csic.es;

Eugènia Martí (Co-Presenter/Co-Author), Center for Advanced Studies of Blanes (CEAB-CSIC), eugenia@ceab.csic.es;

Stephanie N. Merbt (Co-Presenter/Co-Author), Center for Advanced Studies of Blanes (CEAB-CSIC), Spain, stephanie.merbt@ceab.csic.es;

Miquel Ribot (Co-Presenter/Co-Author), Center for Advanced Studies of Blanes (CEAB-CSIC), Spain, mribot@ceab.csic.es;

Xavier Triadó-Margarit (Co-Presenter/Co-Author), Integrative Freshwater Ecology Group (IFE), Centre d’Estudis Avancats de Blanes (CEAB-CSIC), Blanes, Girona, Spain., xtriado@ceab.csic.es;

Emilio O. Casamayor (Co-Presenter/Co-Author), Integrative Freshwater Ecology Group (IFE), Centre d’Estudis Avancats de Blanes (CEAB-CSIC), Blanes, Girona, Spain., casamayor@ceab.csic.es;

Susana Bernal (Co-Presenter/Co-Author), Center for Advanced Studies of Blanes (CEAB-CSIC), Spain, sbernal@ceab.csic.es;

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6/03/2024  |   11:00 - 11:15   |  Freedom Ballroom H/G

Going with the flow (or lack of): Periphyton response to flow intermittency in rivers With global warming and a rise in groundwater extraction, previously perennial rivers are experiencing intermittent flows. New patterns in drying and wetting can shape what primary producer species grow where, when, and in what amount to disrupt river health and alter food webs, for example to impact fisheries. Cyanobacteria, for example, often thrive under low or intermittent water flow and warm conditions, but are less grazeable, lower in food quality, or can produce toxins. We documented and characterized changes in algal and cyanobacterial assemblages from epilithic composites scraped from three riffle cobbles in the San Saba and Concho Rivers during years with lower (2021) and higher (2023) flows. We used microscope counts and fluid imaging (FlowCam5000®) to determine the relative abundance of cyanobacteria and algae (reds, greens, diatoms, and others), and functional groups. We will share modified techniques used to run samples containing algal mats and high in clay-sized particles through the FlowCam®. Changes in temperature and water quality altered distribution patterns for taxa like the red alga Audouinella, and filaments of mat-forming cyanobacteria. Data from this study will contribute to the development of models to predict ecological responses of running waters to different climatic and human-derived pressures.

Paula Furey (Primary Presenter/Author), St. Catherine University, pcfurey@stkate.edu;

Tonya Ramey (Co-Presenter/Co-Author), Texas State University, drtonyaramey@gmail.com;

Weston Nowlin (Co-Presenter/Co-Author), Texas State University, wnowlin@txstate.edu;

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6/03/2024  |   11:30 - 11:45   |  Freedom Ballroom H/G

Recovery of intermittent stream communities across variable drying regimes Intermittent streams dominate stream networks but are historically understudied. The extent of drying in intermittent streams can vary spatiotemporally; some reaches completely dry while others maintain isolated pools. Reaches with isolated pools may provide refugia for stream organisms and contribute to community stability while reaches that completely dry require colonization from perennial reaches as streams rewet. We compared the response and recovery of fish and crayfish communities to summer drying in 10 streams across an intermittency gradient (completely dry vs. isolated pools). The response of crayfish densities to drying was dependent on drying extent, and densities did not recover after streams rewetted. Fish community structure exhibited large shifts during drying, but recovered quickly after streams rewetted. Understanding patterns of recovery and recolonization across a gradient of intermittency is critical for prioritizing conservation measures like environmental flow standards or restoration efforts that keep water for aquatic communities on the landscape.

Lindsey Bruckerhoff (Primary Presenter/Author), Ohio State University, bruckerhoff.2@osu.edu;

Benjamin Kelly (Co-Presenter/Co-Author), Bureau of Land Management, benjamin.kelly@okstate.edu;

Vanessa Rendon (Co-Presenter/Co-Author), Oklahoma State University, karendo@okstate.edu;

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6/03/2024  |   11:45 - 12:00   |  Freedom Ballroom H/G

FOSTERING BIG DATA INTEGRATION USING TEAM SCIENCE: THE AQUATIC INTERMITTENCY EFFECTS OF MICROBIOMES IN STREAMS (AIMS) PROJECT Despite their ubiquity, understanding how flow intermittency impacts stream ecosystem processes and downstream water quality remains elusive. Addressing this challenge requires integrating multiple types of data from hydrology, biogeochemistry and microbial methods to untangle the interactions and effect on water quality. The Aquatic Intermittency effects on Microbiomes in Streams (AIMS) project integrates datasets on hydrology, microbiomes, and biogeochemistry in three regions (Southeastern Forests, Great Plains, Mountain West) to test the overarching hypothesis that physical drivers (e.g., climate, hydrology) interact with biological drivers (e.g., microbes, biogeochemistry) to control water quality in intermittent streams. AIMS was funded under a call for projects focused on “Big Data Solutions to Issues of National Importance” and has increased the infrastructure to study intermittent streams across our three focal regions. This talk will highlight lessons from building an integrative team committed to conducting coordinated science that can result in datasets that are integrated. It will also highlight the emerging results from our regional comparison, including how stream networks dry differently in the three regions and the resulting implications for water chemistry, microbial processes, and influence on microbial and macroinvertebrate community structure.

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

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