Study Links Antarctic Ice Sheet Retreat to Reduced Carbon Uptake in Southern Ocean

Recent research published in Nature Geoscience reveals that the retreat of the West Antarctic Ice Sheet (WAIS) may lead to reduced carbon dioxide absorption in the Southern Ocean. The study found that iron-rich sediments transported by icebergs from West Antarctica during warm periods were highly weathered and not readily bioavailable to marine algae, thereby limiting their growth and the ocean's capacity to sequester carbon dioxide.

Lead author Torben Struve of the University of Oldenburg noted that, typically, an increased supply of iron in the Southern Ocean would stimulate algae growth, enhancing the oceanic uptake of carbon dioxide. However, the team's analysis of sediment cores from the Pacific sector of the Southern Ocean indicated that the iron delivered by icebergs was in a less-soluble form, reducing its availability to algae.

Co-author Gisela Winckler, a geochemist at the Lamont-Doherty Earth Observatory, emphasized that the ocean's ability to absorb carbon isn't fixed. The findings suggest that continued shrinking of the WAIS due to global warming could lead to similar sediment delivery, potentially weakening the Southern Ocean's carbon uptake and creating a feedback loop that may amplify climate change.