Thread by @Ant_Partnership

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Each spring in the Southern Ocean, sometimes seen from space by @NASA satellites, swirling blooms of solar-powered phytoplankton turn CO2 into food for everything else. While we know the blooms are critical to the biological carbon pump, what triggers them is up for debate.

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In #ASLO_Letters, researchers from @IMASUTAS, @ClimateExtremes, @CSIRO & @Ant_Partnership use chlorophyll, phytoplankton carbon & nitrate to understand the best indicator for the timing of blooms - the first study to look at all 3 at once.
➡️ doi.org/10.1002/lol2.1… @aslo_org

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They use data from 7114 profiles from 56 BGC-Argo floats circling #Antarctica to measure the biogeochemistry of the Southern Ocean south of 60°S, like this by @SOCCOMProject. See how the @bgc_argo float rights itself in the water, ready to start a mission of at least 3 years.

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🤖 These drifting robotic BGC-Argo floats are used to track bloom timing by measuring dissolved nitrate (plant fertiliser), phytoplankton carbon (growth rate) and chlorophyll (light-absorbing pigment), year-round to 2000m depth, under ice and even in the winter dark.

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Comparing these 3 shows that phytoplankton make more chlorophyll to adjust to high-latitude low-light conditions, before absorbing more carbon and nitrate at the start of the bloom. When it comes to figuring out the 'bloom trigger', it’s important to use the right indicators.

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Stay in touch with our research on the role of #Antarctica and the @_SouthernOcean in the global #climate system - please sign up to our mailing list at aappartnership.org.au/contact-us/

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