It is obvious that the first life originated in water. Therefore, water bodies support a vast community of plant and animal. Many aquatic plants become troublesome for aquatic animals and human as well such as the aquatic weeds like water hyacinth, Salvinia, Hydrilla, Lemna, Pistia, Wolffia
In addition to higher plants, the lower plants (especially blue-green algae and green algae) have much future prospects, as far as production of biomass (see Enzyme Technology
), conversion of aquatic biomass into biogas / hydrocarbon and abatement of pollution (in sewage oxidation) are concerned.
a member of Pteridophyta, is commonly known as water fern. It grows luxuriantly in stagnant water, for example ponds, pools and lakes. S. molesta
is the world's worst weed known so far. As a serious menace it is known only from Africa, Sri Lanka and India. In India, it predominates in Kerala, Kashmir and North-East states. In Kashmir it is represented by S. natans
and in North-East states by S. cucculata.
In Kashmir, beauty of Dal Lake is gradually fading due to rapid growth of this weed. Recently biogas production from Salvinia
was suggested (see Biogas production from Salvinia
Water Hyacinth (Eicchornia crassipes)
Water hyacinth is the most noxious weed of the world. It grows abundantly in tropical regions in non-saline water in ponds, pools, lakes, reservoirs, rivers and even in paddy field. It is believed that water hyacinth occupies about 2,00,000 acres land in Bihar and 30,000 acres in West Bengal. It grows luxuriantly at temperature 28-30°C. It rapidly multiplies on domestic sewage. Generally the huge amount of biomass is of no use. Nowadays, cultivation of water hyacinth on sewage for minimizing pollution has been suggested. Use of water hyacinth in biogas production is discussed (see Biogas production from Water Hyacinth