Human Health
Thunder Bay

Portland shipwreck and climate change
Harmful Algal Blooms are a concern for the Thunder Bay National Marine Sanctuary. This satellite photo from 2011 shows areas of the Great Lakes that were impacted by a toxic algae bloom (light green). Credit: NASA

Why is it a concern?

Although the sanctuary exclusively manages maritime archaeological resources, it is concerned about harmful algal blooms (HABs) and Escherichia coli bacterial outbreaks that lead to swimming advisories and beach closures, which also may limit the public’s access to sanctuary resources due to risks to human health.  Some HAB-causing algae can release toxins into the water that adversely impact aquatic organisms and humans. Impacts include fish kills and skin and respiratory problems in humans. HABs also discolor water, limiting visibility and making sanctuary visits less enjoyable.  The sanctuary needs to better understand water quality influences not only to improve user access, but to understand its influence on historical resources.

In the Great Lakes, HABs have been linked to natural processes such as warm water and poor water circulation and flow, and anthropogenic causes such as nutrient loading leading to eutrophication. Both can result in large amounts of certain types of phytoplankton (e.g., blue-green algae) accumulating in the water. HABs are increasing in frequency and intensity in the Great Lakes. While they are more prevalent in Lake Michigan and Lake Erie, there have been incidents of HABs on the Thunder Bay shoreline.

Runoff and spills have periodically resulted in high levels of Escherichia coli (E. coli) bacteria in the sanctuary, resulting in beach closures. E. coli is often used as an indicator organism in nearshorewater quality monitoring, and while it may not always cause diseasesin humans, its presence can indicate that water may be contaminatedwith organisms that cause human health impacts such as fever, flu-like symptoms, ear infection, respiratory illness, rashes, gastroenteritis,cryptosporidiosis, and hepatitis. Sources of polluted andcontaminated water have been found to include runoff from urban, suburban and ruralareas; aging sewer infrastructure systems pressed to meet increasingdemands, and contaminated flows from other upland sources. Contributing factors that generate these sources include illicit stormdrain connections, improper disposal of materials or maintenancethat clog pipes and cause overflows, cracked or damaged pipes,overflow of sewer systems during storm events, septic system leaching,and various domestic and wildlife sources.

Overview of Research

Thunder Bay National Marine Sanctuary is actively seeking research partners to conduct work connected to Human Health as a sentinel issue.

Project Name PI and contacts Links


Michigan Department of Natural Resources

USGS Watershed data / Thunder Bay     

U.S. Geological Survey


Science Needs and Questions

  • When and where do HABs occur within TBNMS?
  • What types of human health issues exist in sanctuary waters, and how could they impact public accessibility to sanctuary resources?

Education and Outreach Material

Great Lakes BWET program


Abbott, G.M., J.H. Landsberg, A.R. Reich, K.A. Steidinger, S. Ketchen, C. Blackmore. 2009. Resource guide for public health response to harmful algal blooms in Florida. Fish and Wildlife Research Institute Technical Report TR-14. viii + 132 p.

Harvell, C.D., K. Kim, J.M. Burkholder, R.R. Colwell, P.R. Epstein, D.J. Grimes, E.E. Hofmann, E.K. Lipp, A.D.M.E. Osterhaus, R.M. Overstreet, J.W. Porter, G.W. Smith, G.R. Vasta. 1999. Emerging marine diseases - climate links and anthropogenic factors. Marine Ecology 285:1505-1510.

Office of National Marine Sanctuaries. 2013. Thunder Bay National Marine Sanctuary Condition Report 2013. U.S. Department of Commerce, National Oceanic and Atmospheric Administration, Office of National Marine Sanctuaries, Silver Spring, MD. 80 pp.