Shanmuganandan, Samarajalingam

Department of Geography, Madurai Kamaraj University, Palkalainagar, Madurai-625021, Tamilnadu, India, Tel: +91-452-641022, Fax: +91-452-531056, E-mail: shanmug@eth.net

The temporal and spatial variability of atmospheric transport and deposition of fixed nitrogen to marine systems: a study with reference to Indian Ocean littoral

The iron deposition can alter N₂ fixation rates and hence these studies need to be linked to those of natural and anthropogenic changes in climate and global biogeochemistry. These changes will alter the atmospheric input of aerosols containing iron and other essential trace metals to the ocean, which may cause changes in planktonic productivity and food-web structure, resulting in altered carbon partitioning and biogenic air-sea gas fluxes. The deposition of nitrogen rate is very sensitive to aerosol particle size. Atmospheric reactions significantly alter the nitrogen aerosol size. An in depth study is essential to study the processes and needs to be quantified to understand the regional and global deposition models. There is a variation in the ecological impacts of changes in the deposition of atmospheric fixed nitrogen on euphotic zone. The nature of impacts will be basically different in coastal and open-ocean systems. The present study is an attempt to analyze the temporal and spatial variability of atmospheric transport and deposition of fixed nitrogen in Indian Ocean marine system and also to observe the regional variation in the fixed nitrogen over time and space. The study also probes into the details of anthropogenic-affected changes in climate affecting the biogeochemistry of the Indian Ocean marine ecosystem. The study was based on the secondary data collected from published sources and also from the available case studies in order to identify the major dimensions that possibly explain the temporal and spatial variability of fixed nitrogen in Indian Ocean marine ecosystem. The study observed the anthropogenic pressure in the form of societal emissions of contaminants and nutrients altering the coastal ecology, which in turn resulted into the large-scale impacts on CO₂ uptake, as well as trace gas cycling. Sensitive ecosystems such as coral reefs and intertidal areas are particularly more vulnerable to damages and to those of climate change. In view of the above facts, many nations have set ambitious goals for reducing coastal eutrophication in order to minimize damage to coastal ecosystems.