Why Do Baywatchers Care About Dissolved Oxygen?

While most of the Buzzards Bay community is scraping ice off of their cars, Director of Monitoring Programs Tony Williams is busy restocking Baywatchers Dissolved Oxygen testing kits with new chemical testing reagents for the upcoming 32nd summer season of water testing.

A dissolved oxygen kit ready to go for the 2023 Baywatchers season.

The Baywatchers program is the largest and longest-running volunteer-based coastal monitoring effort in New England. Our dedicated citizen scientists provide scientifically validated data on the health of the waters of Buzzards Bay, which forms the foundation of all the Coalition’s work to restore and protect the Bay.

Of all the parameters that characterize an estuary (a partially enclosed body of water where fresh water from rivers and streams mixes with salt water from the ocean), the level of oxygen that is dissolved in the water is one of the best indicators of the estuary’s health. An estuary with little or no oxygen in its waters cannot support healthy levels of animal or plant life.

Unlike many of the problems plaguing estuaries the consequences of a rapid decline in oxygen set in quickly, and animals must move to areas with higher levels of oxygen or perish. This immediate impact makes measuring the level of oxygen an important means of assessing the status of water quality.

Dissolved Oxygen is just one of the most important factors controlling the presence or absence of estuarine species. In addition to its use in respiration, oxygen is needed to aid in decomposition. An integral part of an estuary’s ecological cycle is the breakdown of organic matter. Like animal and plant respiration, this process consumes oxygen. Decomposition of large quantities of organic matter by bacteria can severely deplete the water of oxygen and make it uninhabitable for many species.

Nitrogen pollution from inadequately treated wastewater (i.e. home septic systems) is the primary source of this problem in Buzzards Bay. Nitrogen fuels the overgrowth of phytoplankton, known as a bloom. The phytoplankton ultimately die, fall to the bottom, decompose, and use up oxygen in the deep waters of the estuary. When oxygen is low, nutrients bound to bottom sediments can be released into the water column, thereby permitting more plankton growth and eventually more oxygen depletion. Other pollutants may also be released from sediments under low oxygen conditions, potentially causing problems for the estuarine ecosystem.

Dissolved Oxygen is one of many types of data collected by the Baywatchers Program. Our Baywatchers collect weekly samples from May until September, providing a wealth of data that helps the Coalition continue our work toward healthy and resilient Buzzards Bay.

Are you interested in helping the Coalition to test water in your community? Become a Baywatcher! Please email Tony Williams, Director of Monitoring Programs, at williams@savebu​zzar​dsbay.org to learn more.

Categories: On the Bay, On the Land

Working to Save Buzzards Bay

The Buzzards Bay Coalition is a membership-supported organization dedicated to improving the health of the Buzzards Bay ecosystem for all through education, conservation, research, and advocacy.

We work to protect clean water on the Bay and on the land: