Harmful Algal Blooms, Hypoxia, and Nutrients Research Webinar Series
Benthic Toxin-Producing Cyanobacteria in Rivers and Streams of the United States
Wednesday, June 24, 2026 from 2:00 to 3:00 p.m. EST
This webinar will provide a comprehensive overview of benthic cyanobacterial blooms in rivers and streams across the United States, highlighting their emerging potential threats to ecosystems, animals, and human health. Attendees will learn about (1) the challenges of sampling and characterizing the risks from these blooms and (2) how EPA’s National Rivers and Streams Assessment was used to characterize the nationwide distribution of benthic cyanobacteria, particularly Microcoleus anatoxicus. The presentation will also cover recent EPA-led studies (2023 to 2025), which evaluated field and laboratory methods at multiple pilot sites, and discuss preliminary findings from four system-scale surveys focused on evaluating the relative impact of harmful cyanobacteria. Additionally, this webinar will include a discussion on how survey findings inform public health protection efforts against harmful benthic cyanobacteria. Finally, presenters will give an overview of EPA’s local partnerships and analytical support in the Mountain West in regions such as southern Utah and the Rocky Mountains.
Presenters and Moderator
Presenters:
Chris Nietch, EPA Office of Applied Science and Environmental Solutions
Chris Nietch is a Research Ecologist with EPA’s Office of Applied Science and Environmental Solutions. Over his 23 years with EPA, his research has focused on harmful algal bloom ecology and risk characterization and how to best apply nutrient pollution reduction programs and practices in watersheds. He also directs research at the U.S. EPA’s Experimental Stream Facility, where he helps lead process-based studies focused on how stressors impact the aquatic life and functioning of small stream ecosystems. He holds a Ph.D. in biological sciences from the University of South Carolina.
Nate Smucker, EPA Office of Applied Science and Environmental Solutions
Nate Smucker is a Research Ecologist with EPA’s Office of Applied Science and Environmental Solutions. His research focuses on characterizing effects of nutrient pollution and watershed conditions on freshwater ecosystems, developing ecological indicators and DNA-based approaches that can be useful to monitoring and assessment programs, and on characterizing the ecology of harmful cyanobacterial blooms in rivers and lakes to improve our understanding and management of them. He holds a Ph.D. in Environmental and Plant Biology from Ohio University.
Marcie Tidd, EPA Region 8
Marcie Tidd is a microbiologist with the EPA’s Region 8 Laboratory Services and Applied Science Division. Her current work involves analysis of cyanotoxins associated with harmful algal blooms, as well as managing the Drinking Water Laboratory Certification Program. Marcie has been with EPA for 22 years, serving the Office of Chemical Safety and Pollution Prevention’s Antimicrobial Division, the Office of Water’s Office of Wetlands, Oceans and Watersheds, and Region 8 for the last 15 years. Marcie holds an M.S. in Environmental Science and Policy from Johns Hopkins University.
Moderators:
- Brenda Rashleigh, EPA Office of Applied Science and Environmental Solutions
- Brenna Friday, EPA Office of Water
About the Webinar Series
Hosted by EPA, this free webinar series is focused on communicating the latest, cutting-edge research related to nutrients and the priority impacts of nutrient pollution: harmful algal blooms (HABs) and hypoxia.
Topics will include regional priorities; regulatory updates; and cutting-edge EPA research related to monitoring and forecasting, prevention, control, and response.
Webinars are typically held bimonthly from 2 to 3 p.m. ET on the last Wednesday of the month. Additional information and registration will be posted closer to the scheduled date and as they become available.
Past Webinar Recordings
Links to closed-captioned recordings of past webinars hosted on EPA's YouTube channel are available below. Certificates cannot be provided for watching the webinar recordings.