Perturbed silicon cycle discussed



Silicon is an abundant element in the minerals and rocks of the Earth's crust. Chemical weathering of these rocks and minerals is the natural source of dissolved silicate in water bodies [Wollast and Mackenzie, 1983], where along with N and P, it is an essential nutrient for diatoms. Diatoms form a major part of the aquatic food chain and play a critical role in marine biogeochemical cycles, especially in the sequestration of carbon dioxide from the atmosphere via the “biological pump” [Dugdale et al., 1995]. It now appears that silicate fluxes to rivers and the coastal water bodies are being increasingly perturbed by human activities with severe adverse impacts on the quality and structure of aquatic ecosystems [e.g., Humborg et al., 2000].