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Bowdoin Buoy Used to Get to the Bottom of Red Tide

Story posted June 29, 2007

Four students, three scientists and one state-of-the-art buoy are all working together to get to the bottom of a recurrent problem in Harpswell Sound. Harmful Algal Blooms (HABs), better known as red tides, have been an annual threat to the ecology of the coast and the livelihood of shellfishers. HABs occur when algae, the simple plants that live in the ocean and form the base of the food chain, produce toxic or harmful effects on people, fish, shellfish, marine animals and birds.

The buoy just before launching from the Argo Maine on Dec. 14, 2006. Underwater instrumentation lies on the deck.

"Harmful algal blooms, a yearly occurrence on the Maine coast, greatly impact our marine resources," says Ed Laine, associate professor of geology at Bowdoin. "During red tides, Maine's Department of Marine Resources has to close clam flats to those whose livelihoods depend on harvesting shellfish."

The Bowdoin Buoy Facility (BBF), a scientific buoy near the Bowdoin College Coastal Studies Center in Harpswell Sound, was installed in December 2006 to study HABs. The BBF was made possible by a grant from the National Science Foundation and is the result of a partnership among Bowdoin, Bigelow Laboratory and St. Joseph's College. It is managed by Prof. Laine; Dr. Collin Roesler, senior research scientist at Bigelow; and Greg Teegarden, marine and environmental science professor at St. Joseph's.

Current meter.jpg
The buoy's underwater current meter covered with marine plant growth

While the secret weapon in the quest to crack the mystery of the HABs is the sophisticated buoy, the research could not be done without the work of four students, who are spending ten weeks this summer grabbing their own evidence from the ocean floor and waters of Harpswell Sound. "It's a real hands-on look at the world," says Laine. "And a really exciting way to teach." Working with Laine, Roesler and Teegarden, the students are studying Alexandrium fundeyense, the toxic plankton organisms that give rise to red tides.

The cysts of Alexandrium rest on the ocean floor, waiting for conditions to become just right to bloom, or they move with the currents into inshore regions where, once again, they bloom in response to just the right situation. To begin to distinguish between these two origins, there is first a need to establish a capability to identify and quantify Alexandrium cysts in samples of water and seafloor sediment.

Shell fragments.jpg
Shell fragments taken from sediment samples

Alison Chase '09 is taking sediment samples from the ocean floor of Harpswell Sound and compares their texture with those indicated on a sonar backscatter map of the area. "Once ground-truthing the sonar data is complete, we can then estimate how much of the sound is mud (as opposed to sand or gravel), since the mud sediments are where the Alexandrium cysts are found in greatest abundance," says Chase.

Millan AbiNader '10 collects and counts the cysts from the sediment samples. "This will allow us to have an idea of the number and location of Alexandrium cysts in the sound," says AbiNader. "I am also comparing current data from the buoy with the PSP (paralytic shellfish poisoning) score in Harpswell Sound, to see if current has any impact on blooms. This research will add to our understanding of the bloom dynamics in Harpswell Sound."

Mike Wolovick '09 calibrates the buoy's optical sensors, which are designed to measure how much chlorophyll, and therefore, how much plankton, is in the water. "However, there are many things that can make the sensors give erroneous readings," says Wolovick. "So I'm taking actual physical water samples and bringing them back to the lab to analyze and compare to the buoy data. By analyzing the water in the lab, we can figure out how much plankton and how much of the nutrients the plankton needs to grow are in the water."


Carl Morrissey '09 is working on developing a Web site based on the data from the buoy and nearby samples. "The goal of the Web site is to present the data in a form that's both informative and easy to read, and supplement it with background information regarding how everything fits in the context of oceanography and HAB analysis," says Morrissey, whose research is funded by a Gibbons fellowship, which promotes the use of technology to solve problems in academic projects. "The site should eventually serve the needs of mariners, students and researchers alike."

Such research in a threatened region meets an urgent need for reliable and continuous monitoring. The data collected will be publicly available and will contribute to the overall Gulf of Maine Ocean Observing System (GoMOOS), a national pilot program that brings hourly oceanographic data from the Gulf of Maine to public health officials, in the event of a red tide outbreak. GoMOOS also provides data to commercial mariners, coastal resource managers, scientists, educators, search and rescue teams, and environmental disaster responders.

Information coming in from the BBF can be viewed here.

Click here to see the buoy in context with other GoMOOS buoys.
(Click on BOW).

Work is underway on a Bowdoin Web portal to highlight the BBF and demonstrate its educational and research roles. Check the Coastal Studies Web site in late August.

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