Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone
he high nutrient–low chlorophyll condition of the Southern Ocean is generally thought to be caused by the low bioavailability of micronutrients, particularly iron, which plays an integral role in phytoplankton photosynthesis. Nevertheless, the Southern Ocean experiences seasonal blooms that generall...
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ftimr:oai:imr.brage.unit.no:11250/3087003 2023-10-01T03:50:40+02:00 Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone Singh, Asmita Fietz, Susanne Thomalla, Sandy J. Sanchez, Nicolas Ardelan, Murat V. Moreau, Sebastian Kauko, Hanna Maria Fransson, Agneta Chierici, Melissa Samanta, Saumik Mtshali, Thato N. Roychoudhury, Alakendra N. Ryan-Keogh, Thomas J. 2023 application/pdf https://hdl.handle.net/11250/3087003 https://doi.org/10.5194/bg-20-3073-2023 eng eng Biogeosciences. 2023, 20 3073-3091. urn:issn:1726-4170 https://hdl.handle.net/11250/3087003 https://doi.org/10.5194/bg-20-3073-2023 cristin:2169595 3073-3091 20 Biogeosciences Peer reviewed Journal article 2023 ftimr https://doi.org/10.5194/bg-20-3073-2023 2023-09-06T22:47:13Z he high nutrient–low chlorophyll condition of the Southern Ocean is generally thought to be caused by the low bioavailability of micronutrients, particularly iron, which plays an integral role in phytoplankton photosynthesis. Nevertheless, the Southern Ocean experiences seasonal blooms that generally initiate in austral spring, peak in summer, and extend into autumn. This seasonal increase in primary productivity is typically linked to the seasonal characteristics of nutrient and light supply. To better understand the potential limitations on productivity in the Antarctic sea-ice zone (SIZ), the photophysiological response of phytoplankton to iron addition (2.0 nM FeCl3) was investigated during autumn along the Antarctic coast off Dronning Maud Land. Five short-term (24 h) incubation experiments were conducted around Astrid Ridge (68∘ S) and along a 6∘ E transect, where an autumn bloom was identified in the region of the western SIZ. Surface iron concentrations ranged from 0.27 to 1.39 nM around Astrid Ridge, and 0.56 to 0.63 nM along the 6∘ E transect. Contrary to expectation, the photophysiological response of phytoplankton to iron addition, measured through the photosynthetic efficiency and the absorption cross-section for photosystem II, showed no significant responses. It is thus proposed that since the autumn phytoplankton in the SIZ exhibited a lack of an iron limitation at the time of sampling, the ambient iron concentrations may have been sufficient to fulfil the cellular requirements. This provides new insights into extended iron replete post-bloom conditions in the typically assumed iron deficient high nutrient–low chlorophyll Southern Ocean Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone publishedVersion Article in Journal/Newspaper Antarc* Antarctic Dronning Maud Land Sea ice Southern Ocean Institute for Marine Research: Brage IMR Antarctic Astrid Ridge ENVELOPE(12.000,12.000,-68.000,-68.000) Austral Dronning Maud Land Southern Ocean The Antarctic Biogeosciences 20 14 3073 3091 |
institution |
Open Polar |
collection |
Institute for Marine Research: Brage IMR |
op_collection_id |
ftimr |
language |
English |
description |
he high nutrient–low chlorophyll condition of the Southern Ocean is generally thought to be caused by the low bioavailability of micronutrients, particularly iron, which plays an integral role in phytoplankton photosynthesis. Nevertheless, the Southern Ocean experiences seasonal blooms that generally initiate in austral spring, peak in summer, and extend into autumn. This seasonal increase in primary productivity is typically linked to the seasonal characteristics of nutrient and light supply. To better understand the potential limitations on productivity in the Antarctic sea-ice zone (SIZ), the photophysiological response of phytoplankton to iron addition (2.0 nM FeCl3) was investigated during autumn along the Antarctic coast off Dronning Maud Land. Five short-term (24 h) incubation experiments were conducted around Astrid Ridge (68∘ S) and along a 6∘ E transect, where an autumn bloom was identified in the region of the western SIZ. Surface iron concentrations ranged from 0.27 to 1.39 nM around Astrid Ridge, and 0.56 to 0.63 nM along the 6∘ E transect. Contrary to expectation, the photophysiological response of phytoplankton to iron addition, measured through the photosynthetic efficiency and the absorption cross-section for photosystem II, showed no significant responses. It is thus proposed that since the autumn phytoplankton in the SIZ exhibited a lack of an iron limitation at the time of sampling, the ambient iron concentrations may have been sufficient to fulfil the cellular requirements. This provides new insights into extended iron replete post-bloom conditions in the typically assumed iron deficient high nutrient–low chlorophyll Southern Ocean Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone publishedVersion |
format |
Article in Journal/Newspaper |
author |
Singh, Asmita Fietz, Susanne Thomalla, Sandy J. Sanchez, Nicolas Ardelan, Murat V. Moreau, Sebastian Kauko, Hanna Maria Fransson, Agneta Chierici, Melissa Samanta, Saumik Mtshali, Thato N. Roychoudhury, Alakendra N. Ryan-Keogh, Thomas J. |
spellingShingle |
Singh, Asmita Fietz, Susanne Thomalla, Sandy J. Sanchez, Nicolas Ardelan, Murat V. Moreau, Sebastian Kauko, Hanna Maria Fransson, Agneta Chierici, Melissa Samanta, Saumik Mtshali, Thato N. Roychoudhury, Alakendra N. Ryan-Keogh, Thomas J. Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone |
author_facet |
Singh, Asmita Fietz, Susanne Thomalla, Sandy J. Sanchez, Nicolas Ardelan, Murat V. Moreau, Sebastian Kauko, Hanna Maria Fransson, Agneta Chierici, Melissa Samanta, Saumik Mtshali, Thato N. Roychoudhury, Alakendra N. Ryan-Keogh, Thomas J. |
author_sort |
Singh, Asmita |
title |
Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone |
title_short |
Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone |
title_full |
Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone |
title_fullStr |
Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone |
title_full_unstemmed |
Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone |
title_sort |
absence of photophysiological response to iron addition in autumn phytoplankton in the antarctic sea-ice zone |
publishDate |
2023 |
url |
https://hdl.handle.net/11250/3087003 https://doi.org/10.5194/bg-20-3073-2023 |
long_lat |
ENVELOPE(12.000,12.000,-68.000,-68.000) |
geographic |
Antarctic Astrid Ridge Austral Dronning Maud Land Southern Ocean The Antarctic |
geographic_facet |
Antarctic Astrid Ridge Austral Dronning Maud Land Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Dronning Maud Land Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Dronning Maud Land Sea ice Southern Ocean |
op_source |
3073-3091 20 Biogeosciences |
op_relation |
Biogeosciences. 2023, 20 3073-3091. urn:issn:1726-4170 https://hdl.handle.net/11250/3087003 https://doi.org/10.5194/bg-20-3073-2023 cristin:2169595 |
op_doi |
https://doi.org/10.5194/bg-20-3073-2023 |
container_title |
Biogeosciences |
container_volume |
20 |
container_issue |
14 |
container_start_page |
3073 |
op_container_end_page |
3091 |
_version_ |
1778526024938553344 |