Iron deposition and climate change impacts on Pacific Ocean biogeochemistry

Tuna swim near the ocean surface. Credit: NOAA

Projections of future nutrient limitation and primary production have implications for fisheries management. The authors used GFDL’s Earth system model, ESM4.1, to explore climate-driven changes in the deposition of dust and iron from the atmosphere to the ocean under a range of climate change scenarios, in an attempt to understand where the “fish food” is going to be and why.

These simulations employed a dynamic approach for iron deposition, reflecting changing atmospheric dust loads, and factoring in wind and precipitation, which affect dust and iron transfer from the atmosphere to the ocean. Under increasing climate change scenarios, ESM4.1 projects drier soil conditions, as well as more dust in the atmosphere and precipitation over the Pacific Ocean toward the end of the 21st century. Elevated levels of future iron delivery to the ocean reduce iron limitation of phytoplankton growth in the central Pacific.