An anchor (from a simple, organised or temporary mooring) can impact the Posidonia oceanica meadow in different ways: (1) At the time of anchoring: breaking of the rhizomes on which it falls or drifts before attaching itself; (2) At depth: the chain in front of the anchor slips on the bottom, under the effect of hydrodynamics and the current, and tears off leaves; (3) During the ascent: the anchor breaks the rhizomes on which it is hooked; in some cases, it can tear off a block of matte. 

The anchoring of a pleasure boat tears off an average of 16 to 34 bundles of Posidonia oceanica (this value is even higher when the rhizomes are detached and the matte is not very consistent).

Marine pollution is a major cause of the destruction of Posidonia oceania.

There are several sources of marine pollution, all of which are man-made:

- Chemicals (such as pesticides, "heavy metals" or components of "anti-fouling" paints) from ships, coastal factories, sewage treatment plants, agriculture... 

- Solid waste (such as plastics) from fishing, industrial or urban activities...

- Atmospheric pollution causing ocean acidification N°3 experience, Satellites images . 

- Excessive organic matter, nitrogen... from coastal aquaculture.

Trawling can cause serious damage to seagrass beds by destroying the plants and increasing turbidity N°2 experience. This can also have a negative impact on fisheries by reducing the fish and shellfish populations living in seagrass beds.

Developments can cause physical shocks and sediment disturbances, changing the composition of the seabed and displacing seagrass beds.    Moreover, urbanization increases turbidity N°2 experience.