SFS Annual Meeting

5/23/2019  |   14:00 - 14:15   |  151 ABC

FRESHWATER SALINIZATION: THE DIRECT AND INDIRECT IMPACTS ON INDIVIDUALS, POPULATIONS, AND FOOD WEBS Freshwater salinization is a worldwide problem due to road de-icing, agricultural activities, and mining. A major challenge is to understand the consequences to biota at multiple organizational levels. At the individual and population levels, we have discovered lethal and sublethal effects of increased salinity, including the decline of sensitive taxa, reduced individual growth, and altered performance. At the community level, we have observed changes in food web structure due to direct and indirect effects. Although many freshwater species and communities are sensitive to increased salinity, we have also discovered that some aquatic species can rapidly evolve a tolerance to salt pollution. While salinization from the most common road salt (NaCl) has received relatively little research attention until recently, there has been even less research attention given to road salt alternatives and additives that have been promoted as being environmentally safe. Our research indicates that alternatives can be even more harmful for some aquatic species than NaCl. Collectively, this work underscores the need to take an integrated approach that bridges the fields of ecology, ecotoxicology, and evolution to understand the consequences of freshwater salinization and mitigate its impacts around the world.

Rick Relyea (Primary Presenter/Author), Rensselaer Polytechnic Institute, relyer@rpi.edu;


Brian Mattes (Co-Presenter/Co-Author), Rensselaer Polytechnic Institute, matteb2@rpi.edu;


William Hintz (Co-Presenter/Co-Author), Rensselaer Polytechnic Institute, billhintz@gmail.com;


Matt Schuler (Co-Presenter/Co-Author), Rensselaer Polytechnic Institute, matt.s.schuler@gmail.com;


Kayla Coldsnow (Co-Presenter/Co-Author), Rensselaer Polytechnic Institute, kaylacoldsnow@gmail.com;


Jennifer Hurley (Co-Presenter/Co-Author), Rensselaer Polytechnic Institute, hurlej2@rpi.edu;


Lovisa Lind (Co-Presenter/Co-Author), Swedish University of Agricultural Sciences, lovalind@gmail.com;


Devin Jones (Co-Presenter/Co-Author), US Environmental Protection Agency, jones.devin@epa.gov;


Aaron Stoler (Co-Presenter/Co-Author), Stockton University, aaron.stoler@stockton.edu;


Presentation:
This presentation has not yet been uploaded.

5/23/2019  |   14:15 - 14:30   |  151 ABC

THE MULTIPLE PATHWAYS THAT SALTS CAN MOVE ACROSS RIPARIAN-STREAM BOUNDARIES. Gradual increases in freshwater salinity is a global trend that threatens riparian and freshwater carbon (C) exchange. Freshwaters cover a small fraction of Earth’s surface but receive at least 1.9 Pg C Y-1 from terrestrial ecosystems, and at least 50% of this is stored in freshwaters. Therefore, terrestrial-aquatic exchanges are essential for understanding global C cycling. Salts typically enter streams from riparian areas via multiple pathways that researchers have not fully quantified. Yet, increased salinization can alter C dynamics through limitation or increased access to sodium and ultimately the quality and quantity of C exchanged between terrestrial and freshwater systems. We conducted laboratory and field studies to identify the riparian-stream pathways of C change across salt gradients. First, salts added to a Louisiana riparian area resulted in a 21% reduction in litter decomposition. Second, direct increases in salt concentrations to streamwater increased, decreased, or did not change the microbial and macroinvertebrate detritivore performance, depending on taxa and ion identity. Finally, riparian plants and aquatic macroinvertebrates took-up and stored sodium. We propose that salt limitation could drive greater cross-boundary C efficiency, while toxicity could drive C decoupling at the riparian-stream interface.

Sally Entrekin (Primary Presenter/Author), Virginia Tech, sallye@vt.edu;


Natalie Clay (Co-Presenter/Co-Author), Louisiana Tech University, nclay@latech.edu;


Connor Gruntz (Co-Presenter/Co-Author), Louisiana Tech, connorgruntz@gmail.com ;


Anastasia Mogilevski (Co-Presenter/Co-Author), University of Central Arkansas, amogilevski1@cub.uca.edu;


Brooke Howard-Parker (Co-Presenter/Co-Author), University of Arkansas, bbhowardparker@gmail.com;


Michelle Evans-White (Co-Presenter/Co-Author), University of Arkansas, mevanswh@uark.edu;


Presentation:
This presentation has not yet been uploaded.

5/23/2019  |   14:30 - 14:45   |  151 ABC

EFFECTS OF LOW-LEVEL INCREASES IN CONCENTRATION OF TWO COMMON SODIUM SALTS ON LEAF LITTER DETRITUS AND ASSOCIATED AQUATIC MICROBIAL COMMUNITIES Freshwater salinization is a global issue due to anthropogenic activities. Sub-lethal salinization effects on freshwater microbes remain understudied, especially regarding specific salt anions. We investigated effects of two common sodium salts (NaCl, NaHCO3) across a sub-lethal concentration gradient (16, 32, 64mg/L Na) relative to unamended streamwater (3mg/L Na) on detrital-associated microbes. One-way ANOVA revealed no statistical differences across treatments for mean microbial biomass (algal, fungal, or bacterial) or % litter mass remaining, but response patterns may be important. NaHCO3 subsidized algal productivity and increased variance through 64mg/L, subsidized fungal productivity up to 32mg/L with steady variance overall, and decreased bacterial productivity and variance. NaCl suppressed algal productivity while increasing variance, subsidized fungal productivity and increased variance up to 32 mg/L, and decreased bacterial productivity and variance. Remaining % litter mass and variance remained stable regardless of treatment. Kruskal-Wallis analysis showed significant decreases in median microbial respiration with increasing NaHCO3 and NaCl; only 32-64mg/L NaCl treatments were lower than streamwater. NaHCO3 increased variation through 32mg/L and NaCl decreased variation for respiration. Results suggest small, sub-lethal salt increases may affect aquatic microbial communities, which could alter carbon flux, and ion identity matters.

Brooke Howard-Parker (Primary Presenter/Author), University of Arkansas, bbhowardparker@gmail.com;


Thomas Williams (Co-Presenter/Co-Author), University of Arkansas, tw016@email.uark.edu;


Natalie Clay (Co-Presenter/Co-Author), Louisiana Tech University, nclay@latech.edu;


Sally Entrekin (Co-Presenter/Co-Author), Virginia Tech, sallye@vt.edu;


Michelle Evans-White (Co-Presenter/Co-Author), University of Arkansas, mevanswh@uark.edu;


Presentation:
This presentation has not yet been uploaded.

5/23/2019  |   14:45 - 15:00   |  151 ABC

STREAM ALGAL RESPONSES TO NATURAL GAS ACTIVITY IN AN AGRICULTURAL LANDSCAPE IN ARKANSAS Resource extraction activity by hydrologic fracturing and horizontal drilling increased rapidly in the Arkansas River Valley and Boston Mountains between 2005-2011. This activity can contribute sediments, salts, and nutrients to fresh water ecosystems that can affect aquatic life. We examined benthic algal responses to natural gas activity metrics, nutrients, and salinization using a combination of field and greenhouse studies over the last 10 years. Field correlational studies found some positive relationships between algal and a broad gradient of landscape natural gas metrics that were not observed in a before-after-impact-control study where low-to-moderate natural gas activity occurred. Natural gas activity in the state was embedded in an agricultural landscape that made mechanisms for algal responses more difficult to identify. In-stream salt and nutrient diffusing substrata experiments suggested that positive responses could be due to increasing nitrogen, as opposed to salt availability in streams with high natural gas activity. Greenhouse experiments suggest that sodium salts may alter benthic algal metabolism, but not algal sodium content at low concentrations (3-64 mg NaCl/L). Future research will further examine pathways by which freshwater salinization can influence stream benthic algal community structure and production.

Michelle Evans-White (Primary Presenter/Author), University of Arkansas, mevanswh@uark.edu;


Sally Entrekin (Co-Presenter/Co-Author), Virginia Tech, sallye@vt.edu;


Bradley Austin (Co-Presenter/Co-Author), University of Arkansas, bjaustin@uark.edu;


Lucy Baker (Co-Presenter/Co-Author), Virginia , lucy.baker@deg.virginia.gov;


Hannah Verkamp (Co-Presenter/Co-Author), University of Arkansas, hjverkamp@gmail.com;


Samuel Dias (Co-Presenter/Co-Author), University of Arkansas, sadias@uark.edu;


Zachary Tipton (Co-Presenter/Co-Author), University of Arkansas - Fayetteville, ztipton@uark.edu;


Natalie Clay (Co-Presenter/Co-Author), Louisiana Tech University, nclay@latech.edu;


Anastasia Mogilevski (Co-Presenter/Co-Author), Gettysburg College, mogian01@gettysburg.edu;


Presentation:
This presentation has not yet been uploaded.

5/23/2019  |   15:00 - 15:15   |  151 ABC

SALTS CAN SUBSIDIZE OR IMPAIR SHREDDER PERFORMANCE: SALT ION TYPE AND PATHWAY OF EXPOSURE MATTER Anthropogenic salinization can impair ecosystems by changing species’ functional capacities, without altering community structure. Few studies document how ion-specific effects could alter shredder performance, either from altered osmoregulatory energy demand or litter quality from microbial exposure. Three microcosm experiments were implemented to identify pathways of ion-specific effects at sub-lethal concentrations: (1) leaf-disks and associated biofilms kept in a gradient (16, 32, and 64 mg/L NaCl or NaHCO3) of salt-amended or unamended (~3 mg/L NaCl) streamwater, (2) shredders (Lepidostoma sp.) kept in a gradient of salt-amended streamwater, and (3) shredders kept in unamended streamwater and fed leaf-disks incubated in a salt-amended streamwater gradient. Compared to streamwater, shredders grew 6x less in NaCl-amended water and excreted 50x more in the highest NaCl treatment, while eating similarly. Shredder growth efficiencies were therefore reduced in NaCl compared to NaHCO3 and streamwater. In contrast, shredders fed salt-incubated leaves displayed increasing growth trends in both salt types. Although shredders ate similarly, they excreted ~8x less from salt-incubated leaves. The enhanced shredder growth efficiencies support a sodium subsidy effect. Results suggest salts impair or subsidize shredder function depending on the ion type and exposure pathway.

Brooke Howard-Parker (Co-Presenter/Co-Author), University of Arkansas, bbhowardparker@gmail.com;


Natalie Clay (Co-Presenter/Co-Author), Louisiana Tech University, nclay@latech.edu;


Michelle Evans-White (Co-Presenter/Co-Author), University of Arkansas, mevanswh@uark.edu;


Sally Entrekin (Co-Presenter/Co-Author), Virginia Tech, sallye@vt.edu;


Anastasia Mogilevski (Primary Presenter/Author), University of Central Arkansas, amogilevski1@cub.uca.edu;


Presentation:
This presentation has not yet been uploaded.