Low Oxygen, No Problem for Polychaetes

Of course, polychaetes can tolerate low dissolved oxygen levels. After all, they can live in oxygen-depleted areas in the mud and sand of the tidal flats. These marine-based worms, according to Living Treasures: The Plants and Animals of Long Island Sound, “work the sediments, bringing nutrients to the mud or sand surface layer and allowing oxygen to penetrate deeper in the mud or sand. They feed on decaying matter, alga and bacteria, and they themselves are prey for larger animals, such as crabs.” They do breathe in oxygen through their skin or gills.

Facts about Polychaetes

• Polychaetes, or bristle worms, are marine annelids, worms that have segmented, ringlike bodies. They are related to earthworms.
• Chaeta is derived from the Greek word chaite, meaning growth of hair or flowing locks. So polychaete means many hairs or many bristles, a reference to the bristles on the worms’ ringlike bodies.
• According to ScienceDirect, there are more than 15,000 described species of polychaetes. Marine Animals of Southern New England and New York, a guide to animals in Long Island Sound, identifies more than 80 species in the Sound. It’s not a comprehensive list, however. The guide did not include rare species.
• Polychaetes can tolerate levels of dissolved oxygen of 1 mg per liter of water, according to the Chesapeake Bay Program. In Long Island Sound, anoxic conditions, in which the environment has extremely little or no oxygen, begin at levels of less than 1 mg/L
• In 1994, the Connecticut Department of Energy and Environmental Protection conducted research to investigate the lowest levels of dissolved oxygen that 16 common fish in Long Island Sound can tolerate. The fish that tolerated the most deoxygenated waters were butterfish with a tolerance of dissolved oxygen levels of <1.3 mg per liter of water followed by Atlantic herring with DO levels of 1.4 mg per liter.

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