Our water quality monitoring program is one of the ways we serve as watchdogs of the health of our waterways. We post data from each monitoring run on our website as soon as it becomes available.
Besides taking water samples from each of the 19 sites we monitor, we also test for pH, salinity, temperature and dissolved oxygen (DO) using a sonde (water quality instrument).
But what does the data signify?
In each issue of our newsletter, we will explore these parameters in order to make the information more understandable.
The last issue was about Dissolved Oxygen (DO), which is required by all marine organisms. It fluctuates daily and seasonally as marine plants generate it during photosynthesis and marine animals consume it. Regulatory agencies have established DO concentrations below which the health of marine organisms is in danger and lower levels below which marine life is not possible.
Low oxygen is referred to as hypoxia and anoxia is defined as no oxygen. Low or no oxygen conditions can result from the decomposition of excess organic materials by microorganisms. Algal blooms are usually short-lived and when they die and decompose, DO is consumed. DO is measured in milligrams per liter. Organisms have their own individual tolerance range. The NYS Department of Environmental Conservation has determined that waters with DO below 3 milligrams per liter (mg/L) are hypoxic and uninhabitable for most marine organisms. DO between 2 and 4 mg/L can cause harm to many organisms with prolonged exposure. Levels below 1 mg/L are considered anoxic and usually fatal for organisms.
Locally on several occasions, DO was found to be less than 3 mg/L in several Cold Spring Harbor locations and in three sample locations in Mill Neck Creek. Information from sampling conducted in 2015-2016 indicates that the estuary has an excess level of nutrients, especially nitrogen, a condition that frequently leads to low DO.
For current water quality data, please visit the water quality data page by clicking on the tab under monitoring. If you would like to subscribe to our newsletter please fill out the form below.
FRIENDS OF THE BAY WATER QUALITY DATA
Friends of the Bay received a Quality Assurance Project Plan from the Environmental Protection Agency in April of 2006 and later updated on June 16, 2020. Friends of the Bay has a long standing water quality monitoring program which began in the late 1990s. Data from 2005 and earlier is available upon request.