SFS Annual Meeting

5/21/2019  |   09:00 - 09:15   |  150 DEF

ESTABLISHING DIDYMOSPHENIA GEMINATA CELLULAR RESPONSE THRESHOLDS TO WATER QUALITY CHANGES USING FOURIER-TRANSFORM INFRARED (FTIR) MICROSPECTROSCOPY The diatom, Didymosphenia geminata, or Didymo, is considered a nuisance species in coldwater streams across the world, forming thick mats that can blanket stream substrate and homogenize benthic habitat. Low phosphorous conditions (<2 µg/L) have been linked to stalk production; however, new research suggests that other water quality parameters can be important in mat formation in some regions. Standard laboratory bioassays for determining D. geminata cell response thresholds to water quality is difficult because it does not survive long in laboratory conditions. We are developing a method that requires short-term incubations (hours to days) and determines cellular level responses to changing water conditions. Fourier-transform infrared (FTIR) microspectroscopy is used to determine the changes in relative protein, lipid, and carbohydrate concentrations that proceed both cell division and stalk production. Specific biomarkers of interest include carbohydrate increases before stalk production and protein increases before cell division. This new cellular level approach may be an important step towards understanding the mechanisms of D. geminata mat formation. Additionally, this FTIR protocol can be broadly applicable to detecting important triggers of growth and/or toxin production in other harmful and nuisance algae species.

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


Samuel Day (Primary Presenter/Author), Tennessee Tech University, sjday42@students.tntech.edu;


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5/21/2019  |   09:15 - 09:30   |  150 DEF

FACTORS AFFECTING NUISANCE ALGAL BLOOMS IN AN AGRICULTURAL STREAM BAYOU An agriculturally cultivated 17 square kilometer impounded stream bayou watershed was studied to assess variables influencing summer (June-September) nuisance algal blooms. Approximately 83% of the watershed is cropped in corn, cotton, soybeans and/or rice. During the three-year study period (2016-2018), total algal and cyanobacteria blooms (measured as chlorophyll a and phycocyanin, respectively) were affected by three major factors. Early summer (June) algal blooms were delayed by elevated suspended sediment (TSS) loads > 144 mg/L limiting light availability. During mid-summer (July-August), TSS settles and/or flushes from the water column, and nutrients (nitrogen and phosphorus) become limiting factors. Peak nuisance algal blooms occur when nutrients, specifically nitrogen, occur at concentrations > 1-2 mg/L. During late summer (September), algal blooms can be significantly mitigated by elevated chromophoric dissolved organic carbon (CDOM) at concentrations > 7 mg/L originating from extensive areas of drying row-crop plant material which can be flushed into the bayou during intense rainfall events. Previous research indicates that current agricultural best-management practices are useful in reducing TSS and nutrient loads entering rivers and streams but less is known about how such practices may reduce CDOM loads.

Richard Lizotte, Jr. (Primary Presenter/Author), USDA Agricultural Research Service, National Sedimentation Lab , richard.lizotte@ars.usda.gov ;


Martin Locke (Co-Presenter/Co-Author), USDA-ARS, martin.locke@ars.usda.gov ;


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5/21/2019  |   09:30 - 09:45   |  150 DEF

FILAMENTOUS ALGAE RELATIONS TO SURFACE AND GROUNDWATER NUTRIENT PATHWAYS IN THE KARST WATERSHED OF THE FIRST NATIONAL RIVER (BUFFALO RIVER, ARKANSAS) Filamentous algae density in the Buffalo River in Arkansas, the first National River established in the US, seems to be increasing in recent decades. In response to extensive filamentous algae blooms in the summers of 2016 and 2017, an investigation was initiated in 2018 to determine relations between algae coverage and nutrient sources and pathways. Understanding the hydrological mechanisms of nutrient transport in this karst area is relatively complex given the many springs, seeps, caves and sinkholes in the watershed that are conduits for water. Filamentous algae coverage and nutrient analyses conducted for samples collected from mainstem sites, adjacent springs, and shallow wells in the summer and fall of 2018 seem to indicate that nutrients entering the Buffalo River through groundwater pathways (i.e. from springs and hyporheic storage in gravel bars) could be as important to filamentous algae growth as nutrients entering from surface-water pathways. Ongoing data collection should provide insight into whether nutrient concentrations in groundwater are exhibiting chronic increases over time or if surface-water/groundwater interactions are so substantial that concentrations in groundwater are indicative of nearby land use and associated surface-water runoff.

Billy Justus (Primary Presenter/Author), USGS, Little Rock, AR, bjustus@usgs.gov;


Lucas Driver (Co-Presenter/Co-Author), USGS, Lower Mississippi-Gulf Water Science Center, ldriver@usgs.gov;


Nathan Wentz (Co-Presenter/Co-Author), Arkansas Dept of Environmental Quality, wentz@adeq.state.ar.us;


Shawn Hodges (Co-Presenter/Co-Author), National Park Service, Buffalo National River, shawn_hodges@nps.gov;


Ashley Rodman (Co-Presenter/Co-Author), National Park Service, Buffalo National River, ashley_rodman@nps.gov;


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5/21/2019  |   09:45 - 10:00   |  150 DEF

RELATING INSTREAM NUTRIENT CONCENTRATIONS TO FILAMENTOUS ALGAE COVERAGE AND DOMINANT ALGAL TAXA DURING SUMMER BASEFLOW IN THE BUFFALO NATIONAL RIVER IN ARKANSAS Filamentous algae (FA) blooms in the middle and lower reaches of the Buffalo National River in northern Arkansas are cause for growing concern among resource managers, conservationists, and the public. The karst geology of the watershed and increasing amounts of animal production and human contact result in a challenging monitoring scenario for the nation’s first National River. A study investigating the association of FA in the Buffalo River to water-quality was initiated in 2018. One aspect of this study involved comparison of nutrient concentrations to qualitative FA coverage and dominant algal taxa. Spirogyra and Rhizoclonium, two taxa known to proliferate with nutrient enrichment, particularly under large N:P ratios, were the dominant FA taxa identified across sites. Nitrate concentrations were consistently higher in adjacent springs than in the mainstem Buffalo River, and FA coverage was often greatest (>50%) at or downstream of spring sites. The presence and relative richness of cyanobacteria taxa and observations of nitrogen-fixing heterocyte cells was generally associated with sites with relatively lower total nitrogen concentrations. Ongoing data collection should provide valuable insight into the association of FA with nutrient sources and pathways in the Buffalo National River.

David Burge (Co-Presenter/Co-Author), Science Museum of Minnesota, dburge@smm.org ;


Billy Justus (Primary Presenter/Author), USGS, Little Rock, AR, bjustus@usgs.gov;


Lucas Driver (Primary Presenter/Author), USGS, Lower Mississippi-Gulf Water Science Center, ldriver@usgs.gov;


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5/21/2019  |   10:00 - 10:15   |  150 DEF

MACRO FILAMENTOUS ALGAE AS BIOINDICATORS IN THE LOWER OLIFANTS RIVERS The poor water quality of Ga-Selati and Olifants Rivers favours the development, growth as well as the distribution of macrofilamentous algae species of Cladophora, Stigeoclonium and Oedogonium. In the Olifants river, changes in the water clarity has been observed in several attempts. Clear water conditions have decreased, and in many cases, the water is turbid for longer periods than expected. High turbid waters were often accompanied by high water flows during periods of high rainfall events and this contributes to SAV and macrofilamentous algae sloughing and scouring off even during periods of growth. Long term monitoring of SAV distribution and growth in these two river systems make historical data crucial in determining the frequencies and magnitudes of high water flows as they result in the drastic displacements of SAV and macro filamentous algae in the environment. Given the current state of the systems, the rivers are under severe pressure from mining, WWTWs, agricultural activities and the system has degraded. UAV mapping of SAV and macrofilamentous algae in the two river systems of Ga-Selati and Olifants improved the understanding on the complex behavior and development of the aquatic vegetation

Tinyiko Salome Mthombeni (Primary Presenter/Author), University of the Witwatersrand/SAEON, tsmthombeni@gmail.com;


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