Narragansett Bay Estuary Program - NBEP



Low dissolved oxygen : the hypoxia threat

In 1998, Dr. Christopher Deacutis of the NBEP presented the first evidence that hypoxia was occurring in Narragansett Bay in summer months. The following year, the NBEP designed, supported and coordinated a volunteer effort to investigate summertime neap (weak) tide oxygen levels in Narragansett Bay. A collaborative group of scientists and environmental professionals (dubbed "the Insomniacs") completed overnight profiles of dissolved oxygen levels throughout the water column for the upper half of Narragansett Bay. The results of their efforts can be found at Brown University. These surveys continued to be coordinated by the NBEP from 1999 through 2003. On August 20, 2003, a team of RIDEM and the NBEP scientists investigated a severe juvenile menhaden kill reported in Greenwich Bay. The team found that the fish died due to lack of oxygen in the water following an extremely severe hypoxic event. The NBEP was a key partner in documenting and interpreting the results of the investigation in light of the NBEP-initiated collaborative D.O. survey data. This report is available in our publications section (The Greenwich Bay Fish Kill - August 2003: Causes, Impacts and Responses). Both Governor Carcieri and the State Legislators responded strongly to this event by establishing committees to study the issue of hypoxia and what can be done to control it. The NBEP testified in front of the state Senate Committee on the Environment concerning causes, and helped to focus state efforts to better control nutrients entering the Bay. The legislators passed a bill the following year requiring that nitrogen (a key nutrient controlling plant growth) be treated at all major RI sewage treatment plants by 2008 ( RIGL § 46-12-3(25). The NBEP continues to work with state agencies like the RIDEM to reach this goal of limiting excess nitrogen entering the upper Bay. The latest projected nutrient decreases are available in a RIDEM report on the progress on nitrogen permit limits. The NBEP continues to play a role in measuring impacts from excess nutrients by helping to maintain the oxygen surveys in the Bay each summer. These effort have now been linked to a team of scientists from Brown University who now process and maintain the database (see photos of our science team at work:). The results and oxygen distribution maps for 1999 to present are available on their web site: http://www.geo.brown.edu/georesearch/insomniacs/data.html In addition, Dr. Deacutis testified at the US EPA public hearing in Worcester MA. (5/9/07) on the Worcester sewage treatment plant (Upper Blackstone Water Pollution Abatement District (UBWPAD) Wastewater Treatment facility) concerning the need for nitrogen limits at that plant in order to minimize Massachusetts pollutant loading to the Bay.	Scientists responding to the 2003 fish kill. Chris Deacutis measuring Dissolved Oxygen in Greenwich Bay. Thousands of dead Menhaden floating in Greenwich Bay during the '03 fish kill.