Spatial distribution of pteropods from North Andaman Sea: Insights into aragonite supply and deposition in low saline, delta shelf regimes

Pteropods are important components of the marine zooplankton. Not only are they crucial parts of the pelagic ecosystem but are also key contributors to the global carbon budget. Their shells sink to the ocean floor contributing to the inorganic carbon supply to the ocean floor. Being aragonitic, they easily dissolve in oceans receiving fresh water. They also dissolve as they sink beyond the Aragonite Saturation Zone, that is, within the top 500 m of the water column, releasing the trapped CO2 into the surrounding waters. Their taxonomic and quantitative distribution on the modern ocean floor can help strengthen estimates of inorganic carbon supply in shallow oceans, which are also susceptible to climate-induced dissolution. The present study, for the first time, reports 18 pteropod taxa, their abundances and spatial distribution from the surface sediments of the Ayeyarwady Delta Shelf in the North Andaman Sea, characterised by a very high influx of riverine water and sediments.