Iron Limitation Drives the Globally Extreme Fluorescence/Chlorophyll Ratios of the Southern Ocean
Abstract The ratio between fluorescence (F) and chlorophyll‐a (Chl)—where fluorescence is measured with a saturating fluorometer—is variable in the world's oceans, with the highest ratios and highest variability observed in the Southern Ocean. While species composition and Chl packaging per cel...
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| Format: | Article |
| Language: | English |
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Wiley
2022-06-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2021GL097616 |
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| author | Christina Schallenberg Robert F. Strzepek Sophie Bestley Bozena Wojtasiewicz Thomas W. Trull |
| author_facet | Christina Schallenberg Robert F. Strzepek Sophie Bestley Bozena Wojtasiewicz Thomas W. Trull |
| author_sort | Christina Schallenberg |
| collection | DOAJ |
| description | Abstract The ratio between fluorescence (F) and chlorophyll‐a (Chl)—where fluorescence is measured with a saturating fluorometer—is variable in the world's oceans, with the highest ratios and highest variability observed in the Southern Ocean. While species composition and Chl packaging per cell are strong drivers for the observed variability, additional factors, including iron limitation, have to this date not specifically been evaluated. Radiometers on biogeochemical (BGC)‐Argo floats allow for an independent estimate of Chl concentration that is based on the light attenuation coefficient, Kd. Making use of 4,000 radiometry profiles from BGC‐Argo floats in the Southern Ocean, we estimate Chl based on Kd and investigate the variability in F/Chl. Our analysis reveals a positive correlation between F/Chl and a proxy for iron limitation based on non‐photochemical quenching dynamics. The strong influence of iron limitation on F/Chl is further corroborated by data from Southern Ocean phytoplankton cultures. |
| format | Article |
| id | doaj-art-7f0bf97391b0442a84dfa1e21370b48f |
| institution | Kabale University |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2022-06-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-7f0bf97391b0442a84dfa1e21370b48f2025-01-22T14:38:16ZengWileyGeophysical Research Letters0094-82761944-80072022-06-014912n/an/a10.1029/2021GL097616Iron Limitation Drives the Globally Extreme Fluorescence/Chlorophyll Ratios of the Southern OceanChristina Schallenberg0Robert F. Strzepek1Sophie Bestley2Bozena Wojtasiewicz3Thomas W. Trull4Institute for Marine and Antarctic Studies University of Tasmania Hobart TAS AustraliaInstitute for Marine and Antarctic Studies University of Tasmania Hobart TAS AustraliaInstitute for Marine and Antarctic Studies University of Tasmania Hobart TAS AustraliaAustralian Antarctic Program Partnership Hobart TAS AustraliaOceans and Atmosphere CSIRO Hobart TAS AustraliaAbstract The ratio between fluorescence (F) and chlorophyll‐a (Chl)—where fluorescence is measured with a saturating fluorometer—is variable in the world's oceans, with the highest ratios and highest variability observed in the Southern Ocean. While species composition and Chl packaging per cell are strong drivers for the observed variability, additional factors, including iron limitation, have to this date not specifically been evaluated. Radiometers on biogeochemical (BGC)‐Argo floats allow for an independent estimate of Chl concentration that is based on the light attenuation coefficient, Kd. Making use of 4,000 radiometry profiles from BGC‐Argo floats in the Southern Ocean, we estimate Chl based on Kd and investigate the variability in F/Chl. Our analysis reveals a positive correlation between F/Chl and a proxy for iron limitation based on non‐photochemical quenching dynamics. The strong influence of iron limitation on F/Chl is further corroborated by data from Southern Ocean phytoplankton cultures.https://doi.org/10.1029/2021GL097616phytoplankton fluorescenceBGC‐ArgochlorophyllfluorometerSouthern Oceaniron limitation |
| spellingShingle | Christina Schallenberg Robert F. Strzepek Sophie Bestley Bozena Wojtasiewicz Thomas W. Trull Iron Limitation Drives the Globally Extreme Fluorescence/Chlorophyll Ratios of the Southern Ocean Geophysical Research Letters phytoplankton fluorescence BGC‐Argo chlorophyll fluorometer Southern Ocean iron limitation |
| title | Iron Limitation Drives the Globally Extreme Fluorescence/Chlorophyll Ratios of the Southern Ocean |
| title_full | Iron Limitation Drives the Globally Extreme Fluorescence/Chlorophyll Ratios of the Southern Ocean |
| title_fullStr | Iron Limitation Drives the Globally Extreme Fluorescence/Chlorophyll Ratios of the Southern Ocean |
| title_full_unstemmed | Iron Limitation Drives the Globally Extreme Fluorescence/Chlorophyll Ratios of the Southern Ocean |
| title_short | Iron Limitation Drives the Globally Extreme Fluorescence/Chlorophyll Ratios of the Southern Ocean |
| title_sort | iron limitation drives the globally extreme fluorescence chlorophyll ratios of the southern ocean |
| topic | phytoplankton fluorescence BGC‐Argo chlorophyll fluorometer Southern Ocean iron limitation |
| url | https://doi.org/10.1029/2021GL097616 |
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