Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone
The 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 general...
Published in: | Biogeosciences |
---|---|
Main Authors: | , , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications
2023
|
Subjects: | |
Online Access: | https://doi.org/10.5194/bg-20-3073-2023 https://doaj.org/article/35f5ef9338d84dc691bc729c17e484fb |
id |
ftdoajarticles:oai:doaj.org/article:35f5ef9338d84dc691bc729c17e484fb |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:35f5ef9338d84dc691bc729c17e484fb 2023-08-27T04:04:53+02:00 Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone A. Singh S. Fietz S. J. Thomalla N. Sanchez M. V. Ardelan S. Moreau H. M. Kauko A. Fransson M. Chierici S. Samanta T. N. Mtshali A. N. Roychoudhury T. J. Ryan-Keogh 2023-07-01T00:00:00Z https://doi.org/10.5194/bg-20-3073-2023 https://doaj.org/article/35f5ef9338d84dc691bc729c17e484fb EN eng Copernicus Publications https://bg.copernicus.org/articles/20/3073/2023/bg-20-3073-2023.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-20-3073-2023 1726-4170 1726-4189 https://doaj.org/article/35f5ef9338d84dc691bc729c17e484fb Biogeosciences, Vol 20, Pp 3073-3091 (2023) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2023 ftdoajarticles https://doi.org/10.5194/bg-20-3073-2023 2023-08-06T00:48:50Z The 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 FeCl 3 ) 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. Article in Journal/Newspaper Antarc* Antarctic Dronning Maud Land Sea ice Southern Ocean Directory of Open Access Journals: DOAJ Articles 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 |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
spellingShingle |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 A. Singh S. Fietz S. J. Thomalla N. Sanchez M. V. Ardelan S. Moreau H. M. Kauko A. Fransson M. Chierici S. Samanta T. N. Mtshali A. N. Roychoudhury T. J. Ryan-Keogh Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
The 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 FeCl 3 ) 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. |
format |
Article in Journal/Newspaper |
author |
A. Singh S. Fietz S. J. Thomalla N. Sanchez M. V. Ardelan S. Moreau H. M. Kauko A. Fransson M. Chierici S. Samanta T. N. Mtshali A. N. Roychoudhury T. J. Ryan-Keogh |
author_facet |
A. Singh S. Fietz S. J. Thomalla N. Sanchez M. V. Ardelan S. Moreau H. M. Kauko A. Fransson M. Chierici S. Samanta T. N. Mtshali A. N. Roychoudhury T. J. Ryan-Keogh |
author_sort |
A. Singh |
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 |
publisher |
Copernicus Publications |
publishDate |
2023 |
url |
https://doi.org/10.5194/bg-20-3073-2023 https://doaj.org/article/35f5ef9338d84dc691bc729c17e484fb |
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 |
Biogeosciences, Vol 20, Pp 3073-3091 (2023) |
op_relation |
https://bg.copernicus.org/articles/20/3073/2023/bg-20-3073-2023.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-20-3073-2023 1726-4170 1726-4189 https://doaj.org/article/35f5ef9338d84dc691bc729c17e484fb |
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_ |
1775354241582366720 |