Seagrasses are a type of submerged aquatic vegetation. They have evolved from terrestrial plants and have become specialized to live in the marine environment. Like terrestrial plants, seagrasses have leaves, roots, flowers and seeds, and manufacture their own food via photosynthesis.
However, unlike land based grass they do not have strong, supportive stems and trunks required to overcome the force of gravity on land. Instead, seagrass blades are supported by the buoyancy of water, remaining flexible when exposed to waves and currents.
A single acre of seagrass can produce over 10 tons of leaves per year. This vast biomass provides food, habitat, and nursery areas for a myriad of adult and juvenile vertebrates and invertebrates. Further, a single acre of seagrass may support as many as 40,000 fish, and 50 million small invertebrates.
Because seagrasses support such high biodiversity, and because of their sensitivity to changes in water quality, they have become recognized as important indicator species that reflect the overall health of coastal ecosystems.
The seagrass ecosystem
As habitat, seagrasses offer food, shelter, and essential nursery areas to commercial and recreational fishery species, and to the countless invertebrates that are produced within, or migrate to seagrasses.
The complexity of seagrass habitat is increased when several species of seagrasses grow together, their leaves concealing juvenile fish, smaller finfish, and invertebrates such as crustaceans, echinoderms, and other groups. Juvenile stages of many fish species spend their early days in the relative safety and protection of seagrasses.
Threats to the seagrass habitat
Seagrasses are subject to a number of stresses such as storms, excessive grazing, disease, and pollution. What effect these stresses have on seagrasses is dependent on both the nature and severity of the particular environmental challenge.
Generally, if only leaves and above-ground vegetation are impacted, seagrasses are generally able to recover from damage within a few weeks. However, when damage is done to roots the plants may never be able to recover .
Get involved with Seagrass monitoring by joining an eco dive with Blue Guru Diving. By doing this you will also be contributing to diving and marine eucation of the local youth. The key to a sustainable future for these tropical marine habitats.