Anthropogenic Iron Deposition Alters the Ecosystem and Carbon Balance of the Indian Ocean Over a Centennial Timescale

Phytoplankton growth in the Indian Ocean is generally limited by macronutrients (nitrogen: N and phosphorus: P) north micronutrient (iron: Fe) south. Increasing atmospheric deposition of dissolved Fe (dFe) into ocean due to human activities can thus lead significant responses from both northern southern ecosystems. Previous modeling studies investigated impacts anthropogenic nutrient on ocean, but their results are uncertain incomplete representations cycling. This study uses a state-of-the-art ecosystem cycling model evaluate transient productivity carbon uptake Ocean, focusing centennial time scale. The includes three major dFe sources represents an internal modulated scavenging, desorption, complexation with multiple, spatially varying ligand classes. Sensitivity simulations show that after century deposition, not uniform competition between phytoplankton community. In particular, diatom, coccolithophore, picoplankton alters balance organic carbonate pumps increasing along 50°S southeastern tropics while decreasing it Arabian Sea. Our reveal important role dynamics controlling sensitivity fluxes under impact over timescale.