A perspective on the Silicate silicon estimation of a wetland ecosystem
Divya S Rajan
Estuarine and wetland habitats have a naturally high level of productivity that in some cases, enhanced by anthropogenic supply of nutrients carried by rivers. Excessive nutrients leads to harmful or noxious algal blooms, shifts in food chains, increased sedimentation of organic particles and ultimately depletion of dissolved oxygen particularly in bottom waters. Ashtamudi lake as a backwater resource is one of the richest source of fishery resources. In the present investigation a knowledge on the silicate content of the upper and lower zones of the Chavara south region of Ashtamudi lake was undertaken. The silicate of surface water ranged from 0 to 5600 μg SiO4.Si/l and the bottom water from 0 to 7700 μg SiO4.Si/l in 2008- 2009. The silicate of surface water ranged from 0 to 6300 μgSiO4.Si/l and the silicate of bottom water from 0 to 5600 μgSiO4.Si/l in 2009-2010.High silicate content may be due to heavy discharge of sewages and fresh water delivered from land drainage carrying silicate leach out from rocks. The increased supply of silicate silicon may be due to the exchange of silicon resulting from a direct reaction between the sediment and the overlying weathering of suspended materials. In this context the nutrient enrichment related adverse effects have to be addressed. All these point to the necessity of formulating suitable conservatory measures ensuring proper operation and maintenance of water quality standards. Sustainable management of this resource has become vital for prevention of over exploitation.