Seaweeds or marine algae are well known group of
marine plants, belonging to Cryptogams. These are
large diversified groups with size ranging from single
cell, such as Chlamydomonas to several meters in length
i.e., Macrocystis. The thalli show less morphological and
anatomical differentiation. Algae are classified on the
basis of pigmentation and their morphological
characters. The four classes thus formed are:
Chlorophyta (Green algae), Phaeophyta (Brown algae),
Rhodophyta (Red algae) and Cyanophyta (Blue-green
algae). The algal species belonging to the first three
classes are particularly important as many industrial
products such as agar, alginate, carrageenan can be
extracted from them. They are also traditionally used as
food in many Asian countries and are becoming popular
in the rest of the world. Seagrasses are the most
common of shallow coastal ecosystems, found virtually
in all seas except in the polar seas. They are adapted to
the marine environments and associated with seaweeds
and sea animals. Seagrass are submerged angiospermic
monocotyledonous plants belonging to two families
(Hydrocharitaceae and Potamogetonaceae). As per our
knowledge, there are 12 genera and about 52 species
distributed throughout the world