epipsammon

The community of microscopic species (e.g., diatoms) that attach themselves to grains of sand.

The benthic microflora of marine sands includes bacteria, blue-green bacteria (cyanobacteria), autotrophic flagellates, and diatoms. Those attached to sand grains are generally known as epipsammon (Fig. 4.1).

The community of biota or fauna that live on top of sand.

These groups are 1) the epipsammon, or surface-dwelling, generally motile macrofauna; 2) the endopsammon, or burrowing species that are too large to live in interstitial spaces; and 3) the mesopsammon, or interstitial fauna. The epipsammon is limited to a few groups such as fish or birds which are strong or speedy enough to exploit this turbulent environment.