Marine Biology

Supratidal fringe zone

 Suprtidal Fringe zone

This upper intertidal zone, also called wave splash or spray zone, is the area lying above the highest high-tide mark that gets moisture only by the ocean spray of crashing waves. This area is a transitional area lying between land and sea and is a harsh and inhospitable area where only a very few specialised organisms can inhabit. The organisms living in this zone include a few terrestrial animals that can tolerate salt spray and occasional immersion and also some marine organisms which can resist exposure and dessication. E.g. gastropod snails (Littorina neritoides), encrusting black lichen (Verrucaria sp., Calothrix sp., and Xanthoria parietina), crabs (Ocypode spp.,), sea-slater isopod (Ligia oceanica), acorn barnacle (Semibalanus balanoides) and occasionally flowering plants.

The periwinkle snail (Littorina littorea) feeds on these algae in the upper intertidal zone. The snails scrape the algae off the rocks with their rasping teeth, called a radula. The scavenging sea-slater, Ligia oceanica is a nocturnal one and takes shelter in damp cracks and crevices during day time.