2.1 The partition of marine environment

The marine environment can be classified into two macro domains: the benthic domain, composed of the seabed and benthic organisms, and the pelagic domain composed of the overlying water column.

The coast is the boundary between the sea and the land, and is partially submerged by the water. It can be high and rocky or low and sandy but it is always formed by different areas (FIG.1_SES2.1):

Fig1_SES2.1 Costal components. Fondazione Cetacea

– littoral zone: the area emerges wet by the waves only when the sea is rough;
– intertidal zone: the area affected by the tide (VIDEO 1_SES2.1). It’s compose by:
a. high tide zone, relatively dry
b. middle tide zone, covered by high tide and exposed by low tide
c. low tide zone, usually wet
– infralitoral: submerged area from the low tide limit to the depth where the light cannot reach.
– circalittoral: submerged area where darkness starts from a deep of 200 meters.

Intertidal Zonation Explained. By Derek Bodreau, https://www.youtube.com/watch?v=Ofyn9aXw8sM

In each zone it is possible to find a characteristic marine organisms adapted to the particular environmental conditions.
For example, in the rocky littoral zone, it’s easy find as animal life sea snails that feed on algae and move according to the movements of the sea or barnacles (FIG.2_SES2.1) that attacked to the rock, conserve sea water to survive during the tide dry period.

Fig2_SES2.1 Amphibalanus improvisus.
By Andrew Butko, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2839441