Hows The Water

4.2.12 Getting Ready For Opening Day

Friends of the Bay citizen scientists are looking forward to starting the water quality monitoring season again on April 2.  It seems like we just finished the season last October.  All of us are hoping that the balmy spring temperatures continue.

Friends of the Bay volunteers monitor the dissolved oxygen, water temperature, salinity content pH  and clarity of the water at nineteen different sites throughout the Oyster Bay/Cold Spring Harbor estuary.  In addition, we take water samples at each of these sites which are then tested for coliform bacteria.  Once a month, nitrogen sampling is conducted at each of these sites.

Dissolved Oxygen (DO) levels are often used to gauge the overall health of the aquatic environment.  When the DO levels are too low (a condition called hypoxia) to non-existent (anoxia) the survival, reproduction, or use of an area by marine life is impaired.   There is a cyclical fluctuation in DO levels over the course of our water quality monitoring season, which runs from the first Monday in April to the last Monday in October.  During the spring the DO levels are generally high and as the air and water temperatures increase the DO levels can drop to 1.0 or below in August.  When September comes with cooler nights and increased rainfall, the readings increase again.  This is an established pattern, but if the DO levels begin to fall too quickly, or do not rebound in the fall, it could be an indicator that the water quality has become impaired.  It will be interesting to see this year if the levels are a little lower than usual, due to the warm temperatures all winter.

Nitrogen is a necessary nutrient in a productive ecosystem, but too much nitrogen fuels the excessive growth of planktonic algae.  The dense algal blooms cloud the water and shade the bottom.  When the algae die and settle to the bottom, they are decayed by bacteria, a process that uses up available oxygen.  This can contribute to low oxygen levels in the water, which will then affect the marine life.  Excess nitrogen is a problem Sound wide, and is a significant water quality impairment.

Friends of the Bay began recording pH levels in 2008.  Ocean acidification is becoming an increasing and serious problem.  Ocean acidification is caused by the increased amount of carbon dioxide being absorbed by the world’s oceans.  According to the Natural Resources Defense Council “The new chemical composition of our oceans is expected to harm a wide range of ocean life — particularly creatures with shells. The resulting disruption to the ocean ecosystem could have a widespread ripple effect and further deplete already struggling fisheries worldwide.

Increased acidity reduces carbonate — the mineral used to form the shells and skeletons of many shellfish and corals. The effect is similar to osteoporosis, slowing growth and making shells weaker. If pH levels drop enough, the shells will literally dissolve.”  This could have a grave impact on our shellfishing industry.  Continued monitoring by Friends of the Bay will track impacts to the Oyster Bay/Cold Spring Harbor estuary.

Coliform bacteria levels are used as an indicator of possible presence of human pathogens within the aquatic environment.  High levels of coliform bacteria can cause the closure of shellfish beds and swimming beaches due to health concerns.

The ospreys are returning to their nests in the harbor areas.  They have been sighted in Cold Spring Harbor, Mill Neck Creek, and at Beaver Dam.  The winter ducks seem to be moving out quickly, perhaps due to the unseasonably warm weather.  We are looking forward to seeing terns and egrets in the next couple of weeks as they return to their summer home.


Friends of the Bay’s mission is to preserve, protect and restore the ecological integrity and productivity of the Oyster Bay/Cold Spring Harbor estuary and the surrounding watershed.