Massive Southern Ocean phytoplankton bloom fed by iron of possible hydrothermal origin

• Published in: Nature Communications
• Main Authors: Schine, Casey M. S., Alderkamp, Anne-Carlijn, van Dijken, Gert, Gerringa, Loes J. A., Sergi, Sara, Laan, Patrick, van Haren, Hans, van de Poll, Willem H., Arrigo, Kevin R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2021
• Subjects: General Physics and Astronomy; General Biochemistry, Genetics and Molecular Biology; General Chemistry; Antarctic; Australian Antarctic Ridge; Pacific; Southern Ocean; The Antarctic; Antarc*
• Online Access: http://dx.doi.org/10.1038/s41467-021-21339-5; http://www.nature.com/articles/s41467-021-21339-5.pdf; http://www.nature.com/articles/s41467-021-21339-5

Abstract Primary production in the Southern Ocean (SO) is limited by iron availability. Hydrothermal vents have been identified as a potentially important source of iron to SO surface waters. Here we identify a recurring phytoplankton bloom in the high-nutrient, low-chlorophyll waters of the Antarctic Circumpolar Current in the Pacific sector of the SO, that we argue is fed by iron of hydrothermal origin. In January 2014 the bloom covered an area of ~266,000 km 2 with depth-integrated chlorophyll a > 300 mg m −2 , primary production rates >1 g C m −2 d −1 , and a mean CO 2 flux of −0.38 g C m −2 d −1 . The elevated iron supporting this bloom is likely of hydrothermal origin based on the recurrent position of the bloom relative to two active hydrothermal vent fields along the Australian Antarctic Ridge and the association of the elevated iron with a distinct water mass characteristic of a nonbuoyant hydrothermal vent plume.