In calm conditions, Posidonia oceanica can develop near average sea level. Maximum depth depends on water transparency (0 up to more than 40 m). Light is one of the most important parameters for the distribution and density of the plant.

Posidonia oceanica dislikes low salinity, which can explain its absence from lagoons and river mouths. However, it can relatively resist high salinity levels.

The plant can develop in a temperature range between 10 and 30 degrees and dislikes too intense hydro dynamism. Storms tear off shoots, some of which will constitute cuttings. They also can erode the “mate”, either directly or by leaching the sediment, which weakens the meadows (indirect impact).

It plays a very important role in sedimentary dynamics. Through its rhizomes, it is fixed to the substrate and keeps the sediment immobile. In addition, it plays a very important role in the beach-dune dynamic, since the Posidonia meadows are a sediment reservoir that feed the beaches and dunes.