Understanding and forecasting the effects of land-sea connections on harmful algal bloom transport in estuaries

Institution: University of Maine
Sponsor: Water Resources Research Institute National Competitive Grants Program (104g)

Estuary on the Maine coast. Photo: Archie Corleone, Shutterstock

Shellfish are filter feeders that pump water through their bodies and consume algae they have flltered from the water, some of which can be toxic to humans. The biotoxins found in some algae can accumulate in shellfish, and humans can become sick when they ingest the shellfish meat. The algae reproduce (or “bloom”) when environmental conditions are favorable, creating a Harmful Algal Bloom (HAB) event.

The toxic diatom Pseudo-nitzschia is an algae species that produces a biotoxin that causes  Amnesic Shellfish Poisoning (ASP), with human health effects that can include short-term memory loss, gastrointestinal problems, and even fatality.

ASP has been a documented problem on the U.S. Pacific coast for over a decade, but the first ASP event in the Northeast occurred only recently, in 2016. At the same time there has been unprecedented warming in the Gulf of Maine, where sea surface temperature is increasing faster than in 99% of global oceans and seas. There is not enough historical evidence to make conclusions about specific environmental conditions driving and transporting Pseudo-nitzschia in coastal and estuarine waters of the Gulf of Maine. This makes it difficult for decision-makers to predict bloom events and employ responsive monitoring and management strategies.

Solutions to ASP problems require increased knowledge and understanding of the environmental conditions coinciding with HABs, as well as HAB dynamics. These are gaps that this project targets. The project team’s approach will focus on the conditions that drive HAB events by analyzing historical data and performing coupled computer simulations to evaluate how water quality, current velocity, wind, freshwater flows from land areas, and tide conditions influence the frequency and magnitude of ASP events in Maine estuaries. The collection of hydrologic and water quality measurements in study areas of Blue Hill and Frenchman Bays will be an important part of this work to document environmental conditions and accurately simulate them, to advance the capacity to predict when and where events may occur.

An important outcome of this work will be a publicly available online forecasting tool that will run continuously updated simulations to provide a “hindcast” showing past conditions through a 2-3 day forecast of future coastal currents. This will be combined with particle tracking around Blue Hill and Frenchman Bays. The forecasting tool will be collaboratively designed with stakeholders e.g., Maine Department of Marine Resources (DMR), Acadia Aquafarms, National Park Service, Waukeag Neck Oyster Farm, to provide information most appropriate to their ASP monitoring and management strategies. This research will provide new solutions for prediction of problematic ASP events and more accurate delineations of the locations and duration of related shellfish-harvesting closures by decision-makers.

Research Team:

  • Team Leader: Lauren Ross, Department of Civil and Environmental Engineering, UMaine
  • Sean Smith, School of Earth and Climate Sciences, UMaine
  • Sean Birkel, Climate Change Institute, UMaine
  • Kohl Kanwit, Maine Department of Marine Resources
  • Taylor Bailey, doctoral student, Department of Civil and Environmental Engineering, UMaine

Project Partners:

  • Kate Hubbard, Florida Fish and Wildlife, Woods Hole
  • Gary Shenk, U.S. Geological Survey, Chesapeake Bay Program
  • Thomas Huntington, U.S. Geological Survey, Maine
  • Charles Culbertson, U.S. Geological Survey, Maine

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