Sea
grasses are the most productive group of marine plants
in the ocean, forming extensive meadows in shallow,
nutrient-rich environments. There are approximately 60
known species that occur in tropical and sub-tropical
waters worldwide. Sea grasses provide shelter and
habitat for juvenile fish and invertebrates, and
effectively filter near-shore habitats of nutrients,
creating an oxygen rich environment. They are also an
important component of the coral reef by filtering and
buffering the flow of water and trapping sediments
before they reach delicate corals. There are currently
about 7 species available to the hobbyist for culture
in the aquarium today. Most species require deep sand
beds (6" or more) as their root systems are
extensive and demand for organic nutrients high. A few
of the pioneer species, such as Halophila and Halodule,
can be planted in shallower substrates as they are
relatively less demanding when compared to Thalassia.