Photophysiological response of 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...
Main Authors: | , , , , , , , , , , , , |
---|---|
Format: | Text |
Language: | English |
Published: |
2023
|
Subjects: | |
Online Access: | https://doi.org/10.5194/bg-2022-245 https://bg.copernicus.org/preprints/bg-2022-245/ |
id |
ftcopernicus:oai:publications.copernicus.org:bgd108492 |
---|---|
record_format |
openpolar |
spelling |
ftcopernicus:oai:publications.copernicus.org:bgd108492 2023-05-15T13:38:41+02:00 Photophysiological response of autumn phytoplankton in the Antarctic Sea-Ice Zone Singh, Asmita Fietz, Susanne Thomalla, Sandy J. Sanchez, Nicolas Ardelan, Murat V. Moreau, Sébastien Kauko, Hanna M. Fransson, Agneta Chierici, Melissa Samanta, Saumik Mtshali, Thato N. Roychoudhury, Alakendra N. Ryan-Keogh, Thomas J. 2023-01-06 application/pdf https://doi.org/10.5194/bg-2022-245 https://bg.copernicus.org/preprints/bg-2022-245/ eng eng doi:10.5194/bg-2022-245 https://bg.copernicus.org/preprints/bg-2022-245/ eISSN: 1726-4189 Text 2023 ftcopernicus https://doi.org/10.5194/bg-2022-245 2023-01-09T17:22:42Z 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 constraints on productivity in the Antarctic Sea-Ice Zone (SIZ), the photophysiological response of phytoplankton to iron addition was investigated during autumn along the Antarctic coast off Dronning Maud Land. Five short-term (24 hr) 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. 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. This confirms that phytoplankton were not iron-limited at the time and that ambient iron concentrations were 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. Text Antarc* Antarctic Dronning Maud Land Sea ice Southern Ocean Copernicus Publications: E-Journals Antarctic Astrid Ridge ENVELOPE(12.000,12.000,-68.000,-68.000) Austral Dronning Maud Land Southern Ocean The Antarctic |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
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 constraints on productivity in the Antarctic Sea-Ice Zone (SIZ), the photophysiological response of phytoplankton to iron addition was investigated during autumn along the Antarctic coast off Dronning Maud Land. Five short-term (24 hr) 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. 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. This confirms that phytoplankton were not iron-limited at the time and that ambient iron concentrations were 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 |
Text |
author |
Singh, Asmita Fietz, Susanne Thomalla, Sandy J. Sanchez, Nicolas Ardelan, Murat V. Moreau, Sébastien Kauko, Hanna M. 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, Sébastien Kauko, Hanna M. Fransson, Agneta Chierici, Melissa Samanta, Saumik Mtshali, Thato N. Roychoudhury, Alakendra N. Ryan-Keogh, Thomas J. Photophysiological response of autumn phytoplankton in the Antarctic Sea-Ice Zone |
author_facet |
Singh, Asmita Fietz, Susanne Thomalla, Sandy J. Sanchez, Nicolas Ardelan, Murat V. Moreau, Sébastien Kauko, Hanna M. Fransson, Agneta Chierici, Melissa Samanta, Saumik Mtshali, Thato N. Roychoudhury, Alakendra N. Ryan-Keogh, Thomas J. |
author_sort |
Singh, Asmita |
title |
Photophysiological response of autumn phytoplankton in the Antarctic Sea-Ice Zone |
title_short |
Photophysiological response of autumn phytoplankton in the Antarctic Sea-Ice Zone |
title_full |
Photophysiological response of autumn phytoplankton in the Antarctic Sea-Ice Zone |
title_fullStr |
Photophysiological response of autumn phytoplankton in the Antarctic Sea-Ice Zone |
title_full_unstemmed |
Photophysiological response of autumn phytoplankton in the Antarctic Sea-Ice Zone |
title_sort |
photophysiological response of autumn phytoplankton in the antarctic sea-ice zone |
publishDate |
2023 |
url |
https://doi.org/10.5194/bg-2022-245 https://bg.copernicus.org/preprints/bg-2022-245/ |
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 |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-2022-245 https://bg.copernicus.org/preprints/bg-2022-245/ |
op_doi |
https://doi.org/10.5194/bg-2022-245 |
_version_ |
1766109760439975936 |