Award: OPP-1643618

Phytoplankton in Antarctic coastal waters grow more rapidly relative to waters farther offshore. This growth is limited by the availability of light for photosynthesis and the supply of the micronutrient dissolved iron. Earlier studies suggest that satellite‐based estimates of phytoplankton growth are related to the melting of nearby floating portions (called ice shelves) of the Antarctic ice sheet. In our study, a computer model, which includes melting of ice shelves, is used to examine the different sources of dissolved iron that supply the well‐lit summer surface waters around Antarctica. Dissolved iron is available in the floating ice shelves, and the direct supply of this iron to coastal waters by melting of the bottom of the ice shelf is important for enhancing biological production. However, melting creates less dense water at the ice shelf base that rises and brings deep waters that contain dissolved iron towards the surface in front of the ice shelf. The model shows that this input provides a larger source of dissolved iron to the open surface waters in many coastal regions than does direct supply from the ice shelf meltwater. This implies that phytoplankton growth may be vulnerable to changes in ice shelf basal melt. This work supported the training of PhD students and results have been widely disseminated at international conferences. Last Modified: 04/27/2021 Submitted by: Kevin R Arrigo