They are typically protected from the full force of wave action by barrier islands or coral reefs. All seagrasses have horizontal stems and regular roots. Seagrasses have a thick cuticle and by themselves are not very nutritious. The organisms that do graze on seagrasses are probably getting most nutrients from the epiphytic growth. When seagrasses die, the detrital matter and decomposing bacteria do provide nutrition.
Most seagrasses are euryhaline, meaning they can take a wide variety of salinities.
In the division Anthophyta there are 3 families. It is found throughout the tropics. This is the prefered food of turtles. Enhalus - can grow into the intertidal zone with Zostera spp. Usually they are subtidal.