Reactive Nitrogen Dynamics in the Mangroves of India

This chapter reviews the reactive nitrogen dynamics in Indian mangroves’ ecosystems. The available literature reveals that in the Indian mangroves the dissolved inorganic nitrogen (DIN) varies seasonally with higher values during the monsoon season. This is due to higher terrestrial runoff with increased N leaching coupled with decreased productivity. Mangrove litter is the major contributor to DIN pool along with inputs from aquaculture farms, industries, and domestic waste. Isotopic studies conducted in the sediment and water column reveal similar results pointing out the increasing anthropogenic contribution of reactive nitrogen species in the mangrove environment. Denitrification processes prevail in the mangrove sediments and may pose a threat by increased production of greenhouse gases. Nitrous oxide flux in studied Indian mangroves range from 4.4 to 208 μg m −2 h −1 and is dominant in regions with higher terrestrial sources and agricultural runoff.