Widespread changes in Southern Ocean phytoplankton blooms linked to climate drivers

• Published in: Nature Climate Change
• Main Authors: Thomalla, Sandy J, Nicholson, Sarah-Anne, Ryan-Keogh, Thomas J, Smith, Marie E
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2023
• Subjects: Climate change; Southern Ocean; Phytoplankton
• Online Access: http://hdl.handle.net/10204/13687; https://doi.org/10.1038/s41558-023-01768-4

Climate change is expected to elicit widespread alterations to nutrient and light supply, which interact to influence phytoplankton growth and their seasonal cycles. Using 25 years of satellite chlorophyll a data, we show that large regions of the Southern Ocean express significant multi-decadal trends in phenological indices that are typically larger (<50ays decade–1) than previously reported in modelling studies (<10days decade–1). Although regionally dependent, there is an overall tendency for phytoplankton blooms to increase in amplitude, decline in seasonality, initiate later, terminate earlier and have shorter durations, except in the ice, which initiate earlier and have longer durations. Investigating relationships with prominent climate drivers highlights regional sensitivities and complexities of multiple interacting aspects of a changing climate. Seasonal adjustments of this magnitude at the base of the food web can de-synchronize energy transfer to higher trophic levels, threatening ecosystem services and impacting global climate by altering natural CO2 uptake. 975–984 This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. Smart Places Ocean Systems and Climate