A new private-public coalition announced this week will monitor the presence of cyanobacteria in the Edgartown, Chilmark and Tisbury Great Ponds this summer, including through maps and a special-purpose website.
Tracing the Problem
The algal bloom in Edgartown Great Pond has prompted much well-justified discussion and concern.The following is intended to provide a little additional detail on prospective solutions to improve the health of the pond.
Green and Ominous
The Edgartown Great Pond is in trouble, its brackish waters out of balance and at the outer limit of their capacity to carry nitrogen. This is a well-known fact, thoroughly documented in the Massachusetts Estuaries Project draft report for the pond which was obtained by this newspaper, published on its Web site and written about a year ago this summer.
Experts are mystified by the bloom of an unknown type of algae this summer on the Edgartown Great Pond that has covered acres of the pond’s surface, choking out light to eelgrass beds and then sinking onto shellfish beds.
A sample of the algae was sent this week to the Smithsonian Institution after attempts to positively identify it through records at the Polly Hill Arboretum and through the Woods Hole Oceanographic Institution were inconclusive.
Edgartown wastewater authorities believe a plan to sewer hundreds of homes in the watershed of the Edgartown Great Pond can achieve the 30 per cent reduction in nitrogen pollution required to restore it to health.
A draft report of the Massachusetts Estuaries Project, obtained and published by the Gazette last week, finds the Great Pond’s water quality is significantly affected by heavy nitrogen loading. The biggest single contributor to the problem is household septic systems, the report found.
Restoring Great Salt Pond
The draft Massachusetts Estuaries Project report on the Edgartown Great Pond obtained by the Gazette last week is required reading for all who live on the Vineyard. The conclusions of the report may be obvious, but no less startling on an Island with a long history of strictly protecting its pristine environment, and they extend well beyond the sandy perimeters of the Edgartown Great Pond: encroaching development and nitrogen escaping from septic systems are polluting Island ponds.
If the Edgartown Great Pond is to be restored to environmental health, town authorities must find a way to cut nitrogen pollution coming from household septic systems by at least 30 per cent, according to a comprehensive scientific study of the pond’s water quality.
