Collaborative announces Cyano MV 

First of its kind program will study cyanobacteria at the Island’s great ponds.

Cyano and public health intern Becca Eyrick and scientific program manager Julie Pringle checking data from a water sample.

The Great Pond Foundation (GPF) has officially announced the creation of MV Cyano, a first-of-its-kind cyanobacteria monitoring program on Martha’s Vineyard.

The pilot program is a collaboration between GPF scientists and local boards of health who are actively monitoring cyanobacteria in the Chilmark, Tisbury, and Edgartown great ponds.

Cyanobacteria, or blue-green algae, are a group of photosynthetic microorganisms that have been around since Earth’s early days, and are found in all Vineyard waters, according to GPF executive director Emily Reddington. They help generate oxygen in the atmosphere, and are one of the most diverse and abundant organisms on the planet. Most cyanobacteria cause no harm, but a few that can grow rapidly or bloom and produce cyanotoxins, which when concentrated, can cause adverse health effects in humans, pets, or livestock who wade in or ingest blooming waters.

The Vineyard’s ponds contain brackish water, which is when freshwater and saltwater mix together. Saltwater from the ocean can come into the ponds, raising the salinity levels and reducing the likelihood of a bloom.

Cyanobacteria are traditionally thought to be driven by phosphorus, but there are some affected by other nutrients, such as nitrogen.

A Chilmark man experienced “disturbing symptoms after being poisoned by cyanobacteria in Chilmark Pond last August while crabbing.

Since this spring, GPF has been monitoring the cyanobacteria through a tiered approach based on the work of Dr. Christopher Gobler, chair of coastal ecology and conservation at Stony Brook University. The process uses fluorometric analysis, putting light through a cuvette to collect data on the abundance and type of phytoplankton in samples from the great ponds. 

The data is put into a spreadsheet, and the synthesized information is given to the local boards of health to help make informed decisions about pond advisories and closures based on Environmental Protection Agency, Massachusetts Environmental Protection, and World Health Organization standards.

To make the information easily accessible to the public, Cyano MV created a color-coded graphic to indicate the cyanobacteria bloom risk level. Green means bloom not present, yellow means cyanobacteria alert, orange means cyanobacteria bloom watch, and red means cyanobacteria bloom advisory. Advisories range from green, which allows swimming, boating, fishing, and consuming shellfish, to red, which advises against those recreational activities. 

“This is a proactive system rather than a reactive system,” Reddington told The Times. 

Maps of up-to-date testing can be found on the MV Cyano page of the GPF website.

Data collected through the first three weeks of June shows blooms are not present in any of the Island ponds. Chilmark Great Pond is the only pond with a yellow designation for parts of the pond, which means it is the season for cyanobacteria blooms, but swimming, boating, paddling, fishing, and consuming shellfish is permitted, and there is a suggestion to use caution for humans, pets, and livestock when ingesting the water.

Boards of health will place advisory signage at the ponds, and maps will be updated online.

The GPF team is made up of Reddington, scientific program manager Julie Pringle, watershed outreach manager David Bouck, summer science interns Maggie Sandusky and Kendal Rudolph, and Cyano/public health intern Becca Eyrick.

Being able to test samples right on-Island, rather than having to send them off-Island, has been a boon for the program. 

“Each week I have a new spreadsheet with new data,” Pringle said. “This is in a format where we can send it over to [Bouck] where he can make those color-coded maps, and that will be really helpful if there’s a bloom that’s localised to a particular part of a pond, which tends to happen because cyanobacteria are buoyant and can be blown by the wind.”

The group takes note of areas where blooms have occurred in the past, such as Doctor’s Creek in Chilmark Pond, which has seen a bloom the past three years, and other places, such as heads of coves.

“Places that are fresher, stagnant, warmer, shallower, and places we know nutrient sources are coming in,” Reddington said. In October, the program will have a full season of data, and be able to observe how cyanobacteria is moving through the ponds.

“That’s what’s novel about this program, not much is known about cyanobacteria in brackish ecosystems,” Pringle said. “The bulk of the research done in the past has been in lakes and ponds that are freshwater.”

An introduction to Cyano MV will be held on Saturday, June 26, at 4 pm via Zoom. For more information and to sign up for the meeting, email


  1. Great story on cyano bActeria. Several years ago my Portuguese Water Dog died from swimming frequently in Duarte Pond & was infected & there seemed to be no cure. It was pretty horrible for her in terms of the infection. I would recommend that no dogs swim in these ponds in the summer.

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