Calcification increases carbon supply, photosynthesis, and growth in a globally distributed coccolithophore
Year: 2024
Type: article
Abstract: Coccolithophores fix organic carbon and produce calcite plates (coccoliths) that ballast organic matter and facilitate carbon export. Photosynthesis consumes carbon dioxide, while calcification produces it, raising questions about whether coccolithophores are a net sink or source of carbon. We characterized the physiology of calcified and noncalcified (“naked”) phenotypes of Emiliania huxleyi (CCMP374) and investigated the relationship between calcification and photosynthesis across a gradient of light (25–2000 μ mol photons m −2 s −1 ) spanning the euphotic zone. Growth and photophysiological parameters increased with light until reaching a mid‐light (150 μ mol photons m −2 s −1 ) maximum for both phenotypes. Calcified cells were characterized by enhanced photophysiology and less photoinhibition. Further, enhanced bicarbonate transport in calcified cells led to higher rates of particulate organic carbon fixation and growth compared to naked cells at mid‐light to high light (150–2000 μ mol photons m −2 s −1 ). Coccolith production was similarly high at mid and high light, but the rate of coccolith shedding was >3‐fold lower at high‐light (1.2 vs. 0.35 coccoliths cell −1 h −1 ). The cellular mechanims(s) of this differential shedding remain unknown and underly light‐related controls on coccosphere maintenance. Our data suggest coccoliths shade cells at high light and that enhanced bicarbonate transport associated with calcification increases internal carbon supplies available for organic carbon fixation.
Source: Limnology and Oceanography
DOI: 10.1002/lno.12656
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Life below water
Open Access status: hybrid
Estimated APC paid: $3,360
Awards: GCR: Collaborative Research: The Convergent Impact of Marine Viruses, Minerals, and Microscale Physics on Phytoplankton Carbon Sequestration, G510336836, Light-dependent regulation of coccolithophore host-virus interactions: mechanistic insights and implications for structuring infection in the surface ocean, GCR: Collaborative Research: The Convergent Impact of Marine Viruses, Minerals, and Microscale Physics on Phytoplankton Carbon Sequestration
OpenAlex ID: W4401719768