Economic Seaweeds of India

The two chief types of plants occurring in the marine environment are the algae and sea grasses. These are capable of synthesizing the complex organic substances from the simple inorganic compounds present in sea water. Sea grasses are the seed producing plants which fall into the botanical division of Spermatophyta, whereas marine algae are the primitive group of plants with no true roots, stems and leaves as observed in higher plants and these come under the division Thallophyta. This division also includes certain fungi and bacteria, the latter especially forming an important group in the organic productivity of the sea. Among the algae in the marine habitats, the microscopic and free floating or swimming forms are known as Phytoplankton. The other macroscopic or attached ones, which often grow in the intertidal and subtidal environments, are commonly referred to as Seaweeds. Most of these marine algae or seaweeds are beautifully coloured and attached to rocks or grow on other plants as epiphytes. A few of them are buried inside the sand and sometimes occur as loose lying communities. Depending upon the type of pigment present in them and other morphological and anatomical characters, macroscopic algae are subdivided into the following four classes: 1.Green Algae (Chlorophyceae) 2. Brown Algae (Phaeophyceae) 3. Red Algae (Rhodophyceae) 4. Blue-green Algae (Myxophyceae) Algae belonging to the first three classes are treated here in detail since they constitute the vast majority of seaweeds of economic importance. Among the blue-green algae, some freshwater species of Nostoc are used as food gelly and many others are capable of fixing nitrogen and maintaining the fertility of the soil. Some information available on the marine flowering plants or sea grasses has also been included in this bulletin