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The Problems of Flow-through Bogs

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Research by Clarkson University environmental engineering major Holly Engel, a student in the Semester in Environmental Science (SES) program at the Marine Biological Laboratory (MBL) in Woods Hole, Mass., supports what Cape Cod cranberry growers already suspected: The traditional “flow-through” bogs have a negative impact on stream quality compared with modern bogs.

Since passage of the 1996 Massachusetts Rivers Protection Act, cranberry growers have not been allowed to construct new flow-through bogs, which are directly adjacent to rivers and streams. There is significant concern that such bogs compromise the health of streams by impeding the migration routes of fish, such as herring, and by polluting the streams through fertilizer and pesticide use. Current practice is to construct bogs away from natural water sources and pump water through them mechanically. However, flow-through bogs are ‘”grandfathered” and currently account for l0-15% of cranberry agriculture on Cape Cod.

Over the past fall at the MBL, Engel compared the health of streams in eight sites on Cape Cod. Of these, two were in flow-through bogs that are being actively used for agriculture, four were in flow-through bogs in either early or older stages of natural restoration, and two were in natural rivers that had never been altered or used for cranberry production. Engel compared the diversity of the streams’ habitat structures, the invertebrate populations that provide food for fish, food webs, and nutrient pollution.  She found that the actively farmed flow-through bogs and those whose restoration is less advanced had less healthy stream systems than the older restoration sites and the sites never used for cranberry growing.

Engel received temperature data for her research from The Coonamessett River Trust, which has been monitoring the restoration of cranberry bogs along the Coonamessett River over the past six years. Engel will be passing the data she collected this fall over to the Trust, so they can use it as a resource in their continuing work to restore and protect the river and its surrounding land. Another student in the SES program, Melanie Poole of Connecticut College, who studied restoration of the vegetation of Coonamessett River bog sites this fall, is also giving her data to the Trust.

Engel, who is a student at Clarkson University conducted her research under Dr. Linda Deegan of the MBL Ecosystems Center. The SES is a 15-week program that provides college students from across the United States with an intensive field and laboratory-based introduction to environmental science.  The program, sponsored by the MBL’s Ecosystems Center, gives students the opportunity to interact with scientists who are conducting leading-edge ecological science research. Engel and 15 other SES students presented their research at a public symposium.

Founded in 1888 as the Marine Biological Laboratory, the MBL is the oldest private marine laboratory in the Americas.

Holly Engel

Clarkson environmental engineering major Holly Engel collects water samples in Middle Bog along the Coonamessett River in Falmouth, Mass. as part of the MBL’s Semester in Environmental Science program.