Global models underestimate the contribution of Antarctic macroalgae to global carbon fixation due to limited coastal surveys at high southern latitudes. This study reports diverse and abundant macroalgal assemblages in the Ross Sea (71.5°-74.5° S), including extensive populations at depths exceeding 70 m and crustose coralline algae as deep as 125 m. Estimates using light modeling and photosynthetic rates suggest Antarctic macroalgae may contribute 0.9-2.8% of global macroalgal carbon fixation, significantly higher than previously thought. Climate change, particularly sea ice changes, is likely to impact Southern Ocean carbon fixation and sequestration.

Leigh W. Tait, Caroline Chin, Wendy Nelson, Steve George, Peter Marriott, Richard L. O'Driscoll, Miles Lamare, Victoria S. Mills, Vonda J. Cummings