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Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone

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dc.contributor.author Singh, Asmita
dc.contributor.author Fietz, S
dc.contributor.author Thomalla, Sandy J
dc.contributor.author Sanchez, N
dc.contributor.author Ardelan, MV
dc.contributor.author Moreau, S
dc.contributor.author Kauko, HM
dc.contributor.author Fransson, A
dc.contributor.author Chierici, M
dc.contributor.author Ryan-Keogh, Thomas J
dc.date.accessioned 2023-10-13T12:10:42Z
dc.date.available 2023-10-13T12:10:42Z
dc.date.issued 2023-07
dc.identifier.citation Singh, A., Fietz, S., Thomalla, S.J., Sanchez, N., Ardelan, M., Moreau, S., Kauko, H. & Fransson, A. et al. 2023. Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone. <i>Biogeosciences, 20(14).</i> http://hdl.handle.net/10204/13155 en_ZA
dc.identifier.issn 1726-4170
dc.identifier.issn 1726-4189
dc.identifier.uri https://doi.org/10.5194/bg-20-3073-2023
dc.identifier.uri http://hdl.handle.net/10204/13155
dc.description.abstract 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 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 postbloom conditions in the typically assumed iron deficient high nutrient–low chlorophyll Southern Ocean. en_US
dc.format Fulltext en_US
dc.language.iso en en_US
dc.relation.uri https://bg.copernicus.org/articles/20/3073/2023/ en_US
dc.source Biogeosciences, 20(14) en_US
dc.subject Phytoplankton photosynthesis en_US
dc.subject Photophysiological response en_US
dc.subject Southern Ocean en_US
dc.title Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone en_US
dc.type Article en_US
dc.description.pages 3073-3091 en_US
dc.description.note © Author(s) 2023. This work is distributed under the Creative Commons Attribution 4.0 License. en_US
dc.description.cluster Smart Places en_US
dc.description.impactarea Ocean Systems and Climate en_US
dc.identifier.apacitation Singh, A., Fietz, S., Thomalla, S. J., Sanchez, N., Ardelan, M., Moreau, S., ... Ryan-Keogh, T. J. (2023). Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone. <i>Biogeosciences, 20(14)</i>, http://hdl.handle.net/10204/13155 en_ZA
dc.identifier.chicagocitation Singh, Asmita, S Fietz, Sandy J Thomalla, N Sanchez, MV Ardelan, S Moreau, HM Kauko, A Fransson, M Chierici, and Thomas J Ryan-Keogh "Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone." <i>Biogeosciences, 20(14)</i> (2023) http://hdl.handle.net/10204/13155 en_ZA
dc.identifier.vancouvercitation Singh A, Fietz S, Thomalla SJ, Sanchez N, Ardelan M, Moreau S, et al. Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone. Biogeosciences, 20(14). 2023; http://hdl.handle.net/10204/13155. en_ZA
dc.identifier.ris TY - Article AU - Singh, Asmita AU - Fietz, S AU - Thomalla, Sandy J AU - Sanchez, N AU - Ardelan, MV AU - Moreau, S AU - Kauko, HM AU - Fransson, A AU - Chierici, M AU - Ryan-Keogh, Thomas J AB - 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 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 postbloom conditions in the typically assumed iron deficient high nutrient–low chlorophyll Southern Ocean. DA - 2023-07 DB - ResearchSpace DP - CSIR J1 - Biogeosciences, 20(14) KW - Phytoplankton photosynthesis KW - Photophysiological response KW - Southern Ocean LK - https://researchspace.csir.co.za PY - 2023 SM - 1726-4170 SM - 1726-4189 T1 - Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone TI - Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone UR - http://hdl.handle.net/10204/13155 ER - en_ZA
dc.identifier.worklist 26990 en_US


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