Marine Biology

6.Oxygen

Oxygen

Oxygen is never limiting in the water bathing the beach, because the turbulence of wave action ensures constant saturation. The water held in the beach or sand flat ameliorates changes in temperature and salinity and also contains oxygen, which is available to the organisms. This supply, however, is used up by the respiration of the organisms and must be replenished. This replenishment comes through interchange of the water with the sea above, and is dependent on the fineness of the sediments. Fine sediments have a slow rate of exchange, and coarse sediments have a rapid exchange. In the fine-grained beaches and particularly protected sand flats, water interchange is slow and may result in reduced oxygen supplies.