Harmful benthic cyanobacteria proliferations in streams and rivers: USEPA research to inform sampling and analytical procedures for risk assessment
Citation:
Nietch, C., Kristina Laidlaw, A. Tatters, H. Mash, J. Lu, J. Lazorchak, T. Sanan, E. Pilgrim, P. Weaver, L. Webb, R. Labiosa, M. Tidd, H. Snook, AND N. Smucker. Harmful benthic cyanobacteria proliferations in streams and rivers: USEPA research to inform sampling and analytical procedures for risk assessment. 2024 Society of Freshwater Science Annual Meeting, Philadelphia, PA, June 02 - 06, 2024.
Impact/Purpose:
Benthic harmful cyanobacteria blooms pose a significant threat to domestic animals, wildlife, and humans. U.S. states, tribes, and local agencies need consistent approaches to characterize relative risk and inform mitigation practices. USEPA is addressing this need with multi-year, multi-site field research and controlled experiments.
Description:
Benthic harmful cyanobacteria blooms pose a significant threat to domestic animals, wildlife, and humans. U.S. states, tribes, and local agencies need consistent approaches to characterize relative risk and inform mitigation practices. USEPA is addressing this need with multi-year, multi-site field research and controlled experiments. In 2023, research focused on evaluating in-stream sampling methods that quantify spatial extent at the reach scale and assess the toxin exposure risk from disturbing benthic mats. A stream mesocosm study designed to control the relative dominance of specific strains of benthic cyanobacteria was conducted in parallel with the field effort. Field measurements and 2200 samples were scheduled among seven field crews, making multiple visits to seven pilot test sites across six states (CA/KS/OH/UT/VA/WA) and was accomplished with 98% completeness. Laboratory analyses are ongoing and include general water quality variables, pigments, microscope counts, and DNA metabarcoding of periphyton samples, qPCR analyses for toxin biosynthesis genes, and several cyanotoxin-specific analyses. All periphyton samples were collected such that measures were normalized to stream bed area and biomass. The same analyses were run on samples from the mesocosm study, but in addition, effects on macroinvertebrates and fish were tested. Preliminary results are providing a) rationale for streamlining field sampling techniques so that more sites can be surveyed in 2024 and b) insight into the variation in benthic cyanobacteria growth forms, community structures, toxins, and their potential effects on stream biota that can help guide recommendations for risk assessment in the future.
