The coastal-marine area is divided into zones where environment conditions (light, wetness, salinity, hydrodynamism, nutrients and typology of substratum) are relatively homogenous in one zone but different from adjacent zones by environmental discontinuities.
The terrestrial part is called the adlittoral region and is followed by four other zones: supralittoral, mediolittoral, infralittoral, circalittoral.
The four zones can then be subdivided as follows:
◦ Rocky Shore
◦ Sandy Shore
◦ Posidonia banquettes
◦ Upper Mediolittoral Zone of Rock Shores
◦ Middle and Lower Mediolittoral Zone of Rock Shores
- Vermettid/Coralline Algal ‘Trottoir’ (or ‘Rim’)
◦ Soft Substratum Shores
◦ Hard Bottom Assemblages
- Cystoseira Communities
◦ Soft Bottom Assemblages
- Seagrass meadows
- Posidonia ‘Barrier Reefs’
◦ Coralline Communities
◦ Maerl Communities
This zone is subdivided into hard and soft substrata. The soft substratum is either of the slow-drying form, with the most common type being Posidonia banquettes, or the rapidly drying form, consisting of sand and burrowing animals. The supralittoral zone is characterised by organisms that require some wetting with seawater but not immersion.
Rocky shores are formed as a result of the erosion of bedrock, which is brought about by the pounding of sea waves. Harsh conditions of wave action combined with weather conditions make this a hostile environment for the survival of most living organisms.
Sandy shore habitats form by way of the deposition of sand and fine sediments as a result of erosion of bedrock. This habitat type is mainly dominated by burrowing animals such as Sandhoppers (Scientific: Talitrus saltator; Maltese: Bergħud tar-Ramel), amphipods, beetles and woodlice. The highest point reached by waves, forming a visible sub-zone on most sandy shores, collects stranded material, which provides a cool moist environment for small invertebrates, both terrestrial and marine (flies, beetles, centipedes, spiders, isopods, amphipods and gastropods).
In the Mediterranean, as well as on the sandy shores in the Maltese Islands, banks of seagrass leaves (Scientific: Posidonia oceanica; Maltese: Alka) and seaweed debris are deposited by wave action. These Posidonia banquettes support an interesting community of terrestrial and marine species including amphipods, snails, spiders, beetles, flies and others.