Three Bays Preservation works to raise awareness of fragility of Barstable's bays.
by Sam Pearsall
Courtesy of CapeCodToday.com
June 20, 2009 - Despite an ominous forecast for Saturday, Three Bays Preservation got a perfect boat day with calm seas, sunshine, and 70s for its annual “eco-adventure” boat cruise on Barnstable’s Three Bays. Four tours were sold out on the Coast Guards’ Freedom that took 30 passengers each on a 90-minute cruise through Cotuit Bay, North Bay, and West Bay. These waterways on the Cape’s south side are interconnected by inlets and open up to the greater Nantucket Sound.
Three Bays Preservation Project Manager, Judy Heller, offered history and background about the area while Woods Hole Oceanographic Institution’s biologist of over forty years, George Hampson, provided details about the fragility of these threatened waterways, known as “the fabric of our community.”
“Our purpose today is to raise awareness of how fragile and beautiful these bays are,” said Heller as Freedom departed from the Cotuit Town Landing with two-dozen community members, some year-round residents and others seasonal vacationers.
Hampson has been collecting water quality data for 11 years for Three Bays Preservation and found the water quality has gone down like a sinking ship. A root cause is an overabundance of nitrogen in the bays. The main sources are septic systems, sewage disposal, and lawn fertilizer.
“You fertilize your lawn to make the grass grow, but it does the same here in the bay except with algae,” said Hampson. “You’re just fertilizing the bay.” Over the years a variety of algae have built up in the bays, including sea lettuce and codium, which is an invasive species from China. In some areas of Three Bays, like Warren’s Cove and Prince’s Cove, algal mats are so dense that instead of swimming, ducks and other birds actually walk through the water on the algae. People cannot swim or kayak in these areas either.
Hampson pointed out a nearby waterside home where native rosa rugosa grew up the embankment between the residents’ lawn and the shore. He explained this is an environmentally friendly way to “intercept the nitrogen” that seeps from septic systems and from non-organic lawn fertilizers into the ocean. Another way to combat algal blooms that occur when waters are flooded with nitrogen is growing oysters and other shellfish, which work to filter the system. Some passengers commented on how tasty the oysters are that are grown in such nitrogen-rich waters.
The oxygen content in the bays is one of the main problems caused by algal blooms, and a main focus of Three Bays Preservation. Using three different instruments, Hampson collected water samples from various depths in Cotuit Bay and found the surface and near-surface oxygen levels to be much higher than deeper depths of up to 20 feet. Low oxygen levels impair the mobility of fish and other marine life to the point that they will wash up on shore and die.
Such low levels are caused because “the water is encapsulated [by the algae]; there’s no movement,” said Hampson. In addition, the decaying algal mats are “scavenging” the little oxygen there is below the surface. Hot, muggy, or overcast days and rainstorms all contribute significantly to algae explosions because photosynthesis is then not working sufficiently.
As the tour winded down, Heller pointed out the bird sanctuary on Dead Neck Island, which Three Bays Preservation owns. Currently there are dozens of species of birds living there, including piping plovers, terns, sandpipers, seagulls, and a pair of rare oyster catcher birds. Parts of the island are fenced off in an effort to keep out the coyotes that swim from the mainland hoping for an avian feast.
The successful day of eco-adventure tours ended at 5:30 p.m. and Jim Power, of J. Power & Company, who was responsible for promoting the event, said there was such an interest in the event and since all four cruises sold out he is planning several more days of cruises for July. For more information about Three Bays Preservation visit www.3bays.org
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