Harmful algal blooms – Cyanobacteria

2017 Melville Pond Bloom



Coordinated monitoring programs (including URIWW staff and volunteers) to document and understand harmful cyanobacteria blooms. Check out cyanos.org to learn how you can get involved – including downloading the bloomWatch app.

(A record of advisories of harmful algal blooms for this year is maintained here. The most recent advisories are near the end of these paragraphs, so please scroll down.)

Melville Pond in Portsmouth has the distinction of being the first advisory posted for a harmful algal bloom in 2017 (see http://www.ri.gov/press/view/30839 or https://patch.com/rhode-island/portsmouth/blue-green-algae-back-melville-pond-state-health-department for more details).  That was followed closely by the ponds in Roger Williams Park (http://www.ri.gov/press/view/30861) and St Mary’s Pond in Portsmouth (http://www.ri.gov/press/view/30860). An advisory was listed for Slack’s Reservoir in Greenville (http://www.ri.gov/press/view/30907)  on 7/13/17, which was lifted on 8/18/17 (http://www.ri.gov/press/view/31214).  Almy Pond had an advisory posted on 7/21/17 (http://www.ri.gov/press/view/30975) and Spectacle Pond was posted on 7/24/17 (http://www.ri.gov/press/view/30991).

Blackamore Pond in Cranston had an advisory posted on 8/1/17 (http://www.ri.gov/press/view/31063). An advisory was posted for Turner Reservoir in East Providence on 8/2/17 (http://www.ri.gov/press/view/31082). Sisson Pond in Portsmouth was posted on 8/4/17 (http://www.ri.gov/press/view/31096).  It is important to recognize that advisories posted for drinking water supply ponds does not indicate that the treated drinking water are unsafe. Water suppliers filter and treat source water to remove cyanobacteria and monitor for toxins. Please see the press releases for details.

The ponds in Roger Williams Park in Providence and Warwick Pond in Warwick were posted on 8/18/17 (http://www.ri.gov/press/view/31213). Slacks Reservoir was posted again on 9/1/17 (http://www.ri.gov/press/view/31327) as was Lawton Valley Reservoir in Portsmouth (http://www.ri.gov/press/view/31324). As of 9/12/2017, people are advised to avoid contact with Mashapaug Pond, but the advisory against contact with Pleasure Lake, located in Roger Williams Park, has been lifted (http://www.ri.gov/press/view/31414).  

Pleasure Pond was put back on the advisory list as of 9/27/17, along with Stafford Pond (Tiverton) and JL Curran Reservoir (Cranston) http://www.ri.gov/press/view/31519). 

As of December 1st advisories were lifted from Stafford, Mashapaug, Warwick, Sisson and St. Mary’s Ponds as well as from Pleasure Lake, Lawton Valley and Turner Reservoirs. However, because of evidence of on-going harmful algal blooms in November, advisories were continued for JL Curran and Slack’s Reservoirs, Almy, Blackamore, Spectacle and Melville Ponds, as well as the Roger Williams Park Ponds (other than Pleasure Lake). See http://www.ri.gov/press/view/31999 for more details. 

With all the rain this spring and  summer we may be in more algal blooms. Many of our lakes and ponds are naturally (and harmlessly) more darkly stained than usual this year from all the runoff. But if the water looks unusually murky or cloudy, or has a distinctive blue-green scum on the surface, it is worth contacting us (eherron@uri.edu or lgreen@uri.edu) to help you figure out what is going on.

Or to report suspected blue-green algae blooms, contact DEM’s Office of Water Resources at 401-222-4700 or DEM.OWRCyano@dem.ri.gov and if possible, send a photograph of the reported algae bloom.

Cyanobacteria, also known as blue-green algae, can form harmful blooms in lakes, ponds, and rivers that make the water cloudy, sometimes even making the water look like pea soup or as if bright green paint has been spilled into the water. Under some circumstances these blooms may produce toxins that could make pets and people sick. A number of local waterbodies experience harmful algal blooms each year – we’ll post those on this page when they occur. This is not just a Rhode Island problem. Check out Poisonous Algae Blooms Threaten People, Ecosystems Across U.S. a story on NPR at http://one.npr.org/i/491831451:491848138. And even New York City’s famous Central Park ponds are not immune https://www.nytimes.com/2017/07/07/nyregion/beware-the-blooms-toxic-algae-found-in-some-city-ponds.html.

Not all algae float. To learn more about algal mats, check out the blog on the New England Chapter of the North American Lake Management Society (http://nec-nalms.org/index.php/2017/08/08/algae-mats/).

New study confirms that humans are responsible for increased cyanobacteria growth since 1800s…see http://www.fondriest.com/news/study-confirms-humans-responsible-for-increased-cyanobacteria-growth-since-1800s.htm for an overview.

Secchi disk in algal scum

To learn more see these websites:

Factsheets and other resources: