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The Producers which fuel Beach food weds include Phytoplankton, microscopic benthic algae and large detached plants such as Kelp, Sargassum seaweed, Sea grasses and Mangrove seeds. Rip currents provide cells of recirculating seawater therefore nutrients. These favour proliferation of diatoms amongst the sand grains. A phytoplankton Chaetoceros armatum that blooms in the ocean under certain conditions becomes deposited on the beach as a familiar green scum.
Diatoms betweens sand grains provide the chief food for bi valves and other filter feeders. Surf and off shore Phytoplankton produce organic matter by photosynthesis. When they wash ashore and are buries in the surface layers of sand these cells are consumes by copepods, nematodes, flatworms and other sand grain fauna. The cells are also broken down by bacteria and Protozoans, which in turn are eaten by sand microbes including water bears and small nematodes.
The fine organic particles released by dead plant and animal cells called detritus are retained near the surface on our wide dissipative beaches. This serves to enrich and widen the food web. The most important of food on many beaches are the stranded clumps of seaweed and sea grasses that get washed ashore. They are rapidly attacked by amphipods after nightfall and are the major food source for the larvae of kelp flies. Amphipods can be seen jumping around clumps of seaweed at night. Scavengers such as Isopods and Ghost Crabs quickly zone in on animals such as dead fish. Sea Jellies, Blue bottles, Blue suns, By the wind sailors, Sea lizards and Purple bubble snails.
Fine organic matter released and trapped by surface sand grains are sieved and filter by the sand bubbler crab whose bubble like castings can be seen characteristically on the low tide strand particularly in the early morning. Both amphipods and isopods become in turn food for beach foraging shore birds such as sandpipers and oyster catchers.
Pipis however can be negatively effected by accumulation of stranded Sea Weed. It prevents their food hopping tide chasing migration as well as their burrowing and feeding patterns. Seaweed that accumulates in the surf zone can be a rich source for amphipods, which in turn attract small predatory fish, which feed on them and inturn shelter amongst the seaweed to escape predatory sea birds.
The beach food web establishes a regime of circulating organic matter, nitrates, phosphates, minerals and through continuous decomposition by bacteria the generation of carbon dioxide. This provides a ready made source of plant food to help jump start the plant pioneers (Spinifex) into initiating the establishment of dunes, the outer skin that protects the inner integrity of all our coastal environments.
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