Influence of Sea Water Ingression on Carbon Sequestration in Soils Under Coastal Agro-ecosystems of Eastern India

Coastal agro-ecosystem covers a good part of Earth’s land cover, and the recent global warming-related sea-level rise may further extend its coverage. We assessed the ability of such agro-ecosystem for stocking organic C. To reveal the reasons thereof, soils were collected from three ecologies along east coast of India. It was observed that soils that experienced occasional visits by sea water were a better niche for organic C. Formation of bigger-sized soil aggregates that occlude organic C and protect it from microbial oxidation, migration of organic C towards relatively recalcitrant pools by attachment of its de-protonated –COO groups onto soil mineral surfaces, besides subdued microbial activity due to salinity, contributed longer persistence to organic C and thus its enrichment in coastal soils. Results suggested that occasional visits of salt-laden sea water to coastal agro-ecosystem might curb C loss from soils and thus CO2 loading in the atmosphere and hence the phenomenon of global warming.