Mesoscale oceanographic meanders influence protist community function and structure in the southern Indian Ocean

Sturm, D, de Vries, J, Balch, WM, Wheeler, G and Brownlee, C 2023 Mesoscale oceanographic meanders influence protist community function and structure in the southern Indian Ocean. Environmental Microbiology.

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The interface between the nutrient-rich Southern Ocean and oligotrophic Indian Ocean creates unique environmental conditions that can strongly influence biological processes. We investigated protist communities across a mesoscale meander of the Subtropical Front within the Southern Indian Ocean. 18S V9 rDNA metabarcoding suggests a diverse protist community in which the dinoflagellates and parasitic Syndiniales were abundant. Diversity was highest in frontal waters of the mesoscale meander, with differences in community structure inside and outside the meander. While the overall community was dominated by mixotrophic taxa, the frontal boundary of the meander had increased abundances of heterotrophic taxa, with potential implications for net atmospheric CO2 drawdown. Pulse amplitude modulated (PAM) fluorimetry revealed significant differences in the photophysiology of phytoplankton communities inside and outside the meander. By using single-cell PAM microscopy, we identified physiological differences between dinoflagellate and coccolithophore taxa, which may have contributed to changes in photophysiology observed at community level. Overall, our results demonstrate that frontal areas have a strong impact on the composition of protist communities in the Southern Ocean with important implications for understanding biological processes in this region.

Item Type: Publication - Article
Additional Keywords: protist community function, Indian Ocean, mesoscale meander, 18S V9 rDNA metabarcoding, pulse amplitude modulated (PAM) fluorimetry, phytoplankton
Subjects: Ecology and Environment
Marine Sciences
Divisions: Marine Biological Association of the UK > Other (MBA)
Depositing User: Ms Kristina Hixon
Date made live: 29 Sep 2023 10:14
Last Modified: 09 Feb 2024 16:56

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