Harmful algae blooms in Voyageurs, Isle Royale focus of new study

Both Voyageurs and Isle Royale National Parks have documented cases of harmful algae blooms (HABs) in park waters. These unique organisms can explode in population during certain conditions, and cause significant harm to human health, ecosystems, and local economies.

The National Park Service and U.S. Geological Survey have launched a project to assess the presence of toxic chemicals produced by certain algae in National Parks including Voyageurs and Isle Royale. In recent years, the Park Service has issued warnings to the public about potentially dangerous blooms at both parks. The “Rapid Response Strategy for Potential Toxin Exposures from HABs in Coastal and Shoreline Areas of National Parks” project is intended to help the Park Service detect and respond to the presence of toxins, which can come and go quickly.

The toxins are produced by cyanobacteria, an ancient organism native to almost all environments on Earth. Their large blooms are also naturally occurring in some waters, but human activity can also make other lakes or rivers susceptible to blooms.

“We’re finding HABs in new areas,” said Jamie Kilgo, project co-lead and marine ecologist at the NPS. “We need to monitor areas where they are a known issue and anticipate where we might find them in the future so we can protect visitors, pets, park staff, volunteers and wildlife.”

Harmful algae can thrive in warm waters, which can result from climate change, and waters with high levels of nutrients like phosphorus or nitrogen. Those nutrients have been discharged by wastewater treatment plants, industrial activity, and agriculture over the past century.

Comprehensive effort

The new project will deploy National Park Service staff and citizen volunteers to conduct measurements of the toxins and other conditions, expanding understanding of when and why toxins are produced at harmful levels.

“It’s important that we cover this wide range for both the toxins and sites in order to fully understand the extent of harmful algal blooms,” said Victoria Christensen, USGS project co-lead. “Therefore, we are also sampling a diverse range of waterbodies, such as rivers, lakes, coastal shorelines and backwater areas, that may harbor different types of blooms and different toxins.”

The study will cover 12 National Parks with freshwater resources, and six parks with marine waters. In addition to Isle Royale and Voyageurs, the parks include:

The USGS says it has developed simple, low-cost tools to measure 25 toxins produced by freshwater cyanobacteria. While harmful algae blooms are usually visible, appearing as a thick green substance on and in the water, the toxins can be present even when blooms are not apparent. Better understanding this dynamic is part of the study.

“We are very excited about this multi-agency collaborative effort,” said Jennifer Graham, USGS project co-lead. “The end goal is to provide the information necessary for the National Park Service to develop comprehensive guidance on HAB monitoring, toxin testing and rapid response protocols.”

Also in Voyageurs, USGS scientists are conducting studies this year of how water level management could be used to reduce cyanobacteria toxins, and whether toxins are present at dangerous levels at night.

The study team conducted its first field season this year, and will continue through 2023.

More information:

• Project Underway to Identify Algal Toxins in US National Park Waterways – U.S. Geological Survey
• NWQP Research on Harmful Algal Blooms (HABs) – U.S. Geological Survey
• Crystal Clear: Algal Toxins in Surface Water at Great Lakes National Parks – National Park Service

Harmful algae a toxicity concern in northern Minnesota lake