Eel grass isn’t actual grass or sea weed, it’s angiosperm, which is a flowering plant, and it can live for many years. They grow under water in estuaries and in shallow coastal areas. One of the main functions of eel grass in an ecosystem is to provide food, breeding areas, and protective nurseries for fish, shell fish, crustaceans, and many other animals. Another main function of theirs is to produce decaying plant matter. Bacteria, worms, and crabs feed on this material. Some of the decaying matter is carried offshore many miles where it is fed upon by fish and other animals thousands of feet below the ocean's surface. Classes Magnoliopsida - Dicots Liliopsida - Monocots The flowering plants (also angiosperms or Magnoliophyta) are one of the major groups of modern plants, comprising those that produce seeds in specialized reproductive organs called flowers, where the ovulary or carpel is enclosed. ... In ecology, an ecosystem is a naturally occurring assemblage of organisms (plant, animal and other living organisms—also referred to as a biotic community or biocoenosis) living together with their environment (or biotope), functioning as a unit of sorts. ... Classes Remipedia Cephalocarida Branchiopoda Ostracoda Maxillopoda Malacostraca The crustaceans (Crustacea) are a large group of arthropods (55,000 species), usually treated as a subphylum. ...