Seagrass is the only marine plant that produces flowers for reproduction. This is because they evolved from a group of terrestrial plants which adapted back to marine conditions about 100 million years ago after first migrating to land roughly 200 million years ago. And how are these flowers pollinated without underwater birds and bees?! it is the waves and water currents which carry seagrass pollen from one flower to another.
Seagrass is an important habitat for juvenile fishes before they grow up and swim out to the coral reef. Seagrass also filters water and produces oxygen. When I snorkel I often watch the small bubbles on the seagrass blades, which disperse into the water allowing fish to breath. Finally, seagrasses have true roots to anchor them to the ground and also hold the sediment to the ocean floor. Thus, without seagrass the clear and beautiful turquoise blue water of tropical oceans would be much darker and more murky from floating sediment.
With the help of my office teammates we recently completed surveys of all of the seagrass beds in Odiongan. Now just 16 more municipalities to go until the province of Romblon has a complete set of data for monitoring change in seagrass beds over time.
Having finished our first series of assessments, we are all experts in seagrass and mangrove species identification. This is a much more challenging task in the Philippines versus Key Largo, Florida: The Philippines has over 40 species of mangroves and about 16 species of seagrass compared to the 3 species of mangroves and 7 species of seagrass common to the Caribbean Sea.
Reference for more info: http://bioscience.oxfordjournals.org/content/62/1/56.full