They occupy hard-bottom subtracts (rocks) and are among the most productive ecosystems on Earth, host an extremely high biodiversity (>100,000 individuals and >200 species per square meter) and provide important ecosystem services. Seagrasses meadows are marine plants that form underwater "grass fields" typically growing half a meter tall from the bottom, and thrives on soft sediments in shallow bays and estuaries. Seagrass are important food sources for animal grazers and host a high biodiversity, including large variety offish and shellfish species.