Photo above: On board the Onrust, Robert Aller and Magali Gerino collect sediment for the Marine Sciences Research Center’s study of seasonal changes that occur in Long Island Sound. When the scientists can’t get out on the water, members of the Port Jefferson/Bridgeport ferry crews collect samples for them. (Photo by Ian Stupakoff)
From Dipping into Long Island Sound to Study the ‘Blooms’ in the Stony Brook Magazine, Winter 1994
Water samples collected from Long Island Sound by ferries that cross from Port Jefferson to Bridgeport are leading scientists from the Marine Sciences Research Center (MSRC) to a greater understanding of how animals survive dramatic seasonal changes.
MSRC scientists are trying to understand how a large, short-term pulse of organic matter, such as a spring “bloom” of phytoplankton, affects the growth and activity of animals living in the sediments and what chemical changes occur there as a result of oxygen depletion.
Dr. Robert Aller and a team of nine researchers were trying to collect water samples over the course of a year in all types of sea conditions, to pinpoint the time of the bloom. Fred Hall, vice president and general manager of the Bridgeport-Port Jefferson Steamboat Company, offered to let his chief engineers collect the samples as the ferries cross the sound.
In late winter and spring, single-cell marine plants exhibit a burst of growth, rapidly dividing and making new cells. This phytoplankton growth, the spring bloom, is followed by death and decay of the cells, which drift down to the sediment, delivering a large pulse of food for the animals and microbes that live there, but depleting the oxygen.
Less than two weeks following a pulse of organic matter, MSRC scientists found that oxygen penetration into the sediment decreases by approximately 75 percent, penetrating only to a depth of about two millimeters.
Studying the disappearance of oxygen from the system and how it affects organisms under natural conditions may help scientists understand the onset of hypoxia from summer blooms in the nutrient over-enriched western Long Island Sound.
Says Dr. Aller, “We are extremely grateful for the efforts of the ferry company to help understand these natural processes.”