Notes on Sea Beach Ecology. Food Sources on Sandy Beaches and Localized Diatom Blooms Bordering Gulf Beaches

Abstract

Food production along sandy beaches is much different from that of rocky beaches. No large algae grow on sand beaches. Small filamentous green algae find footholds upon molluscs, mole crabs, strands of Leptogorgia and logs. Basic food along the sand beach is made up of diatoms, bacteria, unicellular algae and detritus; diatoms are probably the most abundant autotrophic organism; the beach bacteria are largely heterotrophic. All organic materials are returned to the food cycle. Beached animal remains are consumed immediately until their breakdown products ooze away to enrich the sand substrata. The material of logs may not be redistributed until a number of years have passed. Food producing algae are diatoms, green algae, peridinians and blue-greens. Many of them are quite small and must be detected by bacteriological methods. They are probably quite significant.Food production from autotrophic algae appears to be relatively steady compared to drifting materials, which may vary enormously. Various types of food drift in as a result of dinoflagellate blooms, catastrophic cold kills and stranding cetaceans. The river mouth floods bring in material. The artificial jetsam of ships washes up on the beaches. Nutrients and salts are also concentrated on beaches from organic remains.