The interstitial subsoil fauna on the beach of Sarso Island, Red Sea

There is little precipitation in the Red Sea area and therefore little influence of freshwater on the beach. Moreover, the sandy beach of Sarso Island (Farasan Archipelago) is bordered landwards and underneath by solid limestone, preventing subsoil fresh water, if there is any, from penetrating into the beach region.

The salinity of the interstitial water from Sarso beach lies a little above the salinity of the adjacent sea. The microfauna of Sarso beach is composed to a rather big proportion of such species that are known to be characteristical littoral subsoil water species, partially of world wide distribution. The ecological analysis of this fauna, i.e. the freeliving Nematodes, reveals the presence of two distinct associations: 1. the association of the low level subsoil region, close to the sea, with clear interstitial water, subject to regular exchange with the water of the adjcent sea. 2. the association of the high level subsoil region, 4-10 meter distant from the sea, with brownish water.