Image of the Month: August 2021

Moorings are autonomous long-term observation stations that continuously collect measurements at key positions of the global ocean circulation. They help to identify and understand natural fluctuations in the ocean as well as changes caused by climate change. Since 1997, GEOMAR has been operating several moorings in the Labrador Sea, the marginal sea between Canada and Greenland, to continuously measure the deep western boundary current and deep water formation as part of the Atlantic overturning circulation. The basic equipment of a mooring consists of an anchor weight on the seabed with an acoustic releaser and a long wire held upright by buoyancy elements in the water column. The scientists attach various measuring devices to the wire like a string of pearls. When the measuring period of a mooring is over, the wire is separated from the anchor by accustic signals, and the buoyancy elements bring the wire and instruments back to the surface. On board, the data from the measuring instruments are read out. Equipped with replaced wear parts and charged batteries, the mooring is then deployed again.

Photo: Patricia Handmann / GEOMAR

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