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Harmful Algal Blooms, Hypoxia, and Nutrients Research Webinar Series

Decorative compilation of pictures depicting harmful algal blooms and nutrient sources.

July 2, 2025: 2pm ET

Applying EPA’s National Nutrient Inventory to quantify landscape nutrient inputs and interception to support state and local water quality objectives

Register Here

Sunrise over farm fields
  1. An Introduction to the EPA’s National Nutrient Inventory– Meredith Brehob, U.S. EPA Office of Research and Development (ORISE)

    The National Nutrient Inventory (NNI) provides estimates of major nutrient fluxes within the contiguous US. This presentation will highlight key features of the NNI, describe major insights into nutrient pollution trends, and introduce a suite of related water quality modeling projects in the Nutrient Inventory Portfolio.

  2. Quantifying 30 Years of spatially explicit catchment and watershed nutrient budgets through the NNI in StreamCat  – Selia Markley, U.S. EPA Office of Research and Development (ORISE)

    This presentation will discuss the benefits of incorporating the NNI into StreamCat, providing annual time series (1987-2017) of nitrogen and phosphorus inputs, removal by crop harvest, and management relevant metrics for all 2.6 million stream catchments and watersheds across the conterminous U.S. These data points in StreamCat can assist users in developing watershed-specific nutrient management plans. We present uses of these data for assessing surface and groundwater areas and discuss possible future research.

  3. Past, present, and potential landscape nutrient interception by wetlands across CONUS – Scott Alford, U.S. EPA Office of Research and Development (ORISE) 

    Wetlands are effective in reducing nutrient loads in surface waters, but there is a need to optimize allocation of conservation efforts to efficiently maximize the likelihood of water quality improvements. This presentation describes efforts to quantify nutrients flowing through wetlands and identify existing and potential wetlands that maximize attenuation of excess landscape nutrients across the conterminous United States (CONUS). This analysis and database will provide an optimized CONUS-wide wetland conservation framework to aid local communities in tailoring their nutrient reduction strategies.

Presenters and Moderator 

  • Meredith Brehob, EPA Office of Research and Development (ORISE) | Meredith Brehob is an aquatic ecologist with an ORISE fellowship at the U.S. EPA’s Office of Research and Development. In this role, she works on applying national data to assess nutrient impacts on freshwater ecosystems and drinking water systems. Meredith has a Master of Science degree in Natural Resources and Environmental Science from the University of Nevada, Reno. 
  • Selia Markley, EPA Office of Research and Development (ORISE) | Selia is a post-bachelors ORISE fellow within the Pacific Ecological Systems Division working with Marc Weber, Ryan Hill, and Jana Compton. She earned her bachelor’s degree from the University of Virginia in environmental sciences and statistics. Her studies and work have focused on nutrients, water quality, and statistical modeling.
  • Scott Alford, EPA Office of Research and Development (ORISE) | Scott is an ORISE postdoctoral fellow with the US EPA’s ORD Freshwater Ecology Branch in Corvallis, Oregon under the mentorship of Dr. Ryan Hill. Scott holds a PhD in Fisheries and Aquatic Sciences from the University of Florida and has a background in estuarine ecology. Scott’s ORISE project focuses on using spatial analyses to quantify nutrient interception by wetlands across CONUS. 
  • Moderator: Robert Sabo, EPA Office of Research and Development | Robert is a scientist at the EPA’s Office of Research and Development and is the research lead for ORD’s National Nutrient Inventory Research Portfolio, a multi-agency effort

About the Webinar Series

Related Resources

  • Nutrients and HABs research
  • Receive invites for upcoming webinars
  • Science Matters Newsletter

Hosted by EPA's Office of Research and Development, Office of Water, and regional offices, 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. 

Upcoming webinar dates and topics are subject to change. Additional information and registration will be posted closer to the scheduled date and as they become available.

Upcoming 2025 Webinar Topics

Topic
Applying EPA's National Nutrient Inventory to Quantify Landscape Nutrient Inputs and Interception to Support State and Local Water Quality Objectives
Characterizing Risk from Harmful Benthic Cyanobacteria in Streams and Rivers

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.

Date Topic
5/7/2025 Connecting Soil Health and Water Quality in Agricultural Systems
3/26/2025 Application of Stable Isotopes to Understand Environmental Processes in Multiple Habitats
11/20/2024 Health Effects and Ecology of Anatoxin-Producing Cyanobacteria
9/25/2024

Coastal Dissolved Oxygen Dynamics and a Brief Introduction to the Hypoxia Task Force

7/31/2024 Climate Change: Nutrient and Sediment Impacts

5/22/2024

Using Wetlands to Reduce Nutrient Loadings to Rivers and the Coast
3/27/2024 Genetic Science Applications in Predicting Cyanobacterial Blooms
1/31/2024 Development and Application of HABs Forecasting Science

Water Research

  • Watersheds Research
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    • Harmful Algal Blooms, Hypoxia, and Nutrients Research Webinars
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Contact Us about Water Research
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Last updated on June 12, 2025
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