Salp blooms drive strong increases in passive carbon export in the Southern Ocean

• Published in: Nature Communications
• Main Authors: Décima, Moira, Stukel, Michael R., Nodder, Scott D., Gutiérrez-Rodríguez, Andrés, Selph, Karen E., Dos Santos, Adriana Lopes, Safi, Karl, Kelly, Thomas B., Deans, Fenella, Morales, Sergio E., Baltar, Federico, Latasa, Mikel, Gorbunov, Maxim Y., Pinkerton, Matt
• Other Authors: Asian School of the Environment
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2023
• Subjects: Science::Biological sciences; Southern Ocean; Zooplankton; Marsden; New Zealand
• Online Access: https://hdl.handle.net/10356/169740; https://doi.org/10.1038/s41467-022-35204-6

The Southern Ocean contributes substantially to the global biological carbon pump (BCP). Salps in the Southern Ocean, in particular Salpa thompsoni, are important grazers that produce large, fast-sinking fecal pellets. Here, we quantify the salp bloom impacts on microbial dynamics and the BCP, by contrasting locations differing in salp bloom presence/absence. Salp blooms coincide with phytoplankton dominated by diatoms or prymnesiophytes, depending on water mass characteristics. Their grazing is comparable to microzooplankton during their early bloom, resulting in a decrease of ~1/3 of primary production, and negative phytoplankton rates of change are associated with all salp locations. Particle export in salp waters is always higher, ranging 2- to 8- fold (average 5-fold), compared to non-salp locations, exporting up to 46% of primary production out of the euphotic zone. BCP efficiency increases from 5 to 28% in salp areas, which is among the highest recorded in the global ocean. Published version This study was funded by the Ministry for Business, Innovation and Employment (MBIE) of New Zealand, NIWA core programs Coast and Oceans Food Webs (COES) and Ocean Flows (COOF), the Royal Society of New Zealand Marsden Fast-track award to M.D., and NSF award #OCE-1756610 to M.R.S. and K.E.S.