Marine science professor targets harmful red tide in Casco Bay

Greg Teegarden wants to know much more about how red tide develops in nearby Casco Bay. A sophisticated tracking buoy purchased with a National Science Foundation grant should now give him and his students a much better picture of these toxic algae blooms by collecting new kinds of data in Harpswell Sound - a part of the bay that suffers from recurring red tides and the shellfish contamination it causes.

Dr. Greg Teegarden

Marine science professor Greg Teegarden stands in front of a sophisticated tracking buoy that has been installed in Harpswell Sound, a “hot spot” where red tide toxicity levels are often the highest in Casco Bay. Real-time data from the buoy and from field studies could lead to an understanding of how red tide develops in the Sound.

Dr. Teegarden, a marine science professor who has published widely on red tide, relies on the buoy to send real-time profiles on weather conditions, tides, temperature, salinity, current speeds, nutrient concentrations, and chlorophyll concentrations in order to track how toxic algae blooms develop. The buoy continuously records and transmits these conditions, all of which can point to algae levels in the water.

"We hope ... to be able to use the buoy's monitors to develop a set of environmental indicators that would signal an imminent red tide," says Teegarden.

Although other buoys like this one form part of the Gulf of Maine Ocean Observing System (GoMOOS) in the open ocean, this buoy is unique because of its location relatively near shore. "Open-water buoys are important and have done a wonderful job monitoring conditions for open-water fishermen. But a near-shore buoy is really significant for shellfishers, because when they have to shut down shellfish flats for red tide contamination, it really harms the local economy," says Teegarden.

He expects to create an empirical model of how harmful algal blooms develop in Harpswell Sound, an important indicator region. The area is among the first to exhibit toxic shellfish, and toxicity levels there are often the highest and longest-lasting of any in Casco Bay. If Teegarden's research leads to understanding how these devastating blooms arise, it can help scientists predict the blooms and help coastal towns manage these events.

The buoy data has already indicated that surface currents seem to retain water in Harpswell Sound, so that Alexandrium, the algae that causes red tide, may not be flushed out readily.

Teegarden and his students will also conduct traditional plankton sampling methods to assess growth of Alexandrium and the ocean conditions coinciding with its growth. According to Teegarden, "The combination of continuous monitoring of ocean conditions with a high-tech buoy and traditional sampling gives us a great shot at developing a warning system that will benefit marine resource managers and users."

Teegarden collaborated with scientists at Bowdoin College, the University of Maine and Bigelow Laboratory for Ocean Sciences on the grant; the scientists will be working together on the project and sharing information. The Davis Conservation Fund also donated funds to the research project, which is expected to last three years.