Characterization of phytoplankton productivity and bio-optical variability in a polar marine ecosystem
Knowledge of Southern Ocean carbon cycling is limited by a paucity of phytoplankton primary productivity (PP) and spectral absorption data in this globally-important region. We measured 13C-based PP in the Indian sector of Southern Ocean (ISSO) during austral summer 2017, examining its link with spe...
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ftunivtsydney:oai:opus.lib.uts.edu.au:10453/153444 2023-05-15T18:24:56+02:00 Characterization of phytoplankton productivity and bio-optical variability in a polar marine ecosystem Kerkar, AU Tripathy, SC Hughes, DJ Sabu, P Pandi, SR Sarkar, A Tiwari, M 2022-01-22T23:27:50Z application/pdf http://hdl.handle.net/10453/153444 English eng PERGAMON-ELSEVIER SCIENCE LTD Progress in Oceanography 10.1016/j.pocean.2021.102573 Progress in Oceanography, 2021, 195 0079-6611 1873-4472 http://hdl.handle.net/10453/153444 info:eu-repo/semantics/closedAccess 0403 Geology 0405 Oceanography Oceanography Journal Article 2022 ftunivtsydney 2022-03-13T13:53:04Z Knowledge of Southern Ocean carbon cycling is limited by a paucity of phytoplankton primary productivity (PP) and spectral absorption data in this globally-important region. We measured 13C-based PP in the Indian sector of Southern Ocean (ISSO) during austral summer 2017, examining its link with spectral absorption coefficients and phytoplankton size structure derived from an absorption-based global model. Phytoplankton productivity was assessed at both coastal (60°S-69°S) and frontal stations (40°S-60°S), characterized by silicate- replete and -deplete water masses, respectively (indicated by measured nutrient ratios) to capture a range of phytoplankton growth conditions. Bio-optical relationships were used as indicators of phytoplankton community size structure and to assess the extent of cellular pigment packaging - a phenomenon reported previously for phytoplankton in this region. Blue-Red (B/R) ratios of phytoplankton absorption (aph) spectra indicated that microphytoplankton (more prone to “package effects”) were the dominant size class at most sites sampled. Overall, PP was better explained by aph (R2 = 0.85) than total chlorophyll-a (R2 = 0.64) in surface waters. The a*ph (675)-chlorophyll-a relationship explained package effects more effectively in frontal regions (R2 = 0.63) than stations further south (R2 = 0.30). The global absorption-based model captured smaller (pico, nano) phytoplankton size classes but failed to identify larger microphytoplankton, underscoring the need for region-specific algorithm modifications. Our findings improve existing understanding of spatio-temporal trends in PP and bio-optical variability within the Indian Sector of the Southern Ocean (ISSO) – knowledge that is essential to improve capacity to retrieve PP from satellite-based models in this region. Article in Journal/Newspaper Southern Ocean University of Technology Sydney: OPUS - Open Publications of UTS Scholars Austral Indian Southern Ocean |
institution |
Open Polar |
collection |
University of Technology Sydney: OPUS - Open Publications of UTS Scholars |
op_collection_id |
ftunivtsydney |
language |
English |
topic |
0403 Geology 0405 Oceanography Oceanography |
spellingShingle |
0403 Geology 0405 Oceanography Oceanography Kerkar, AU Tripathy, SC Hughes, DJ Sabu, P Pandi, SR Sarkar, A Tiwari, M Characterization of phytoplankton productivity and bio-optical variability in a polar marine ecosystem |
topic_facet |
0403 Geology 0405 Oceanography Oceanography |
description |
Knowledge of Southern Ocean carbon cycling is limited by a paucity of phytoplankton primary productivity (PP) and spectral absorption data in this globally-important region. We measured 13C-based PP in the Indian sector of Southern Ocean (ISSO) during austral summer 2017, examining its link with spectral absorption coefficients and phytoplankton size structure derived from an absorption-based global model. Phytoplankton productivity was assessed at both coastal (60°S-69°S) and frontal stations (40°S-60°S), characterized by silicate- replete and -deplete water masses, respectively (indicated by measured nutrient ratios) to capture a range of phytoplankton growth conditions. Bio-optical relationships were used as indicators of phytoplankton community size structure and to assess the extent of cellular pigment packaging - a phenomenon reported previously for phytoplankton in this region. Blue-Red (B/R) ratios of phytoplankton absorption (aph) spectra indicated that microphytoplankton (more prone to “package effects”) were the dominant size class at most sites sampled. Overall, PP was better explained by aph (R2 = 0.85) than total chlorophyll-a (R2 = 0.64) in surface waters. The a*ph (675)-chlorophyll-a relationship explained package effects more effectively in frontal regions (R2 = 0.63) than stations further south (R2 = 0.30). The global absorption-based model captured smaller (pico, nano) phytoplankton size classes but failed to identify larger microphytoplankton, underscoring the need for region-specific algorithm modifications. Our findings improve existing understanding of spatio-temporal trends in PP and bio-optical variability within the Indian Sector of the Southern Ocean (ISSO) – knowledge that is essential to improve capacity to retrieve PP from satellite-based models in this region. |
format |
Article in Journal/Newspaper |
author |
Kerkar, AU Tripathy, SC Hughes, DJ Sabu, P Pandi, SR Sarkar, A Tiwari, M |
author_facet |
Kerkar, AU Tripathy, SC Hughes, DJ Sabu, P Pandi, SR Sarkar, A Tiwari, M |
author_sort |
Kerkar, AU |
title |
Characterization of phytoplankton productivity and bio-optical variability in a polar marine ecosystem |
title_short |
Characterization of phytoplankton productivity and bio-optical variability in a polar marine ecosystem |
title_full |
Characterization of phytoplankton productivity and bio-optical variability in a polar marine ecosystem |
title_fullStr |
Characterization of phytoplankton productivity and bio-optical variability in a polar marine ecosystem |
title_full_unstemmed |
Characterization of phytoplankton productivity and bio-optical variability in a polar marine ecosystem |
title_sort |
characterization of phytoplankton productivity and bio-optical variability in a polar marine ecosystem |
publisher |
PERGAMON-ELSEVIER SCIENCE LTD |
publishDate |
2022 |
url |
http://hdl.handle.net/10453/153444 |
geographic |
Austral Indian Southern Ocean |
geographic_facet |
Austral Indian Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
Progress in Oceanography 10.1016/j.pocean.2021.102573 Progress in Oceanography, 2021, 195 0079-6611 1873-4472 http://hdl.handle.net/10453/153444 |
op_rights |
info:eu-repo/semantics/closedAccess |
_version_ |
1766205966754250752 |