Grayce P. Storey
Human beings depend upon oxygen to sustain life and marine animals depend on oxygen also. These animals use the oxygen dissolved in the water they live in. When the amount of dissolved oxygen in the water falls below a certain level the animals will acquire a condition call hypoxia.
Most animals in an oxygen depleted area will suffer stress and eventually suffocate. Some mobile animals may leave the area while the less mobile remaining will be trapped and die if the circumstances are prolonged.
It is believed that in the Long Island Sound the problem is intensified by excess nutrients entering the Sound via sewage treatment plants, runoff, and the atmosphere. In 1987 the Long Island Sound’s studies determined that hypoxia is more of a problem in the western half of the Sound. In 1988 the hypoxia conditions were slightly less severe while west of Bridgeport and Port Jefferson showed evidence of oxygen being below acceptable levels.
Microscopic plants (phytoplankton) growth is stimulated by the nutrients nitrogen and phosphorus in order to live. If there is an excess supply of nutrients phytoplankton grows in large quantities.
They produce oxygen during the day and at night they require oxygen for respiration especially when the phy to plankton dies it sinks and uses up still more oxygen from the water.
Hypoxia can occur naturally, especially in summer. This occurs when the sun warms the surface of the water forming a lighter layer that the water below. “This stratification reduces mixing between surface and bottom waters, so oxygen added to the upper part of the water column, through interface with the atmosphere and the photo synthesis of marine plants, is largely prevented from replenishing the oxygen in deeper waters.”
Computer models are being developed to betted understand the cause of hypoxia.
Hypoxia plays a role in animal reproduction. Studies indicate that the population of some animals (lobsters, window pane flounder) was affected by the presence of hypoxia.