Inhibition of marine photosynthesis by ultraviolet radiation: Variable sensitivity of phytoplankton in the Weddell-Scotia Confluence during the austral spring
To assess the potential impacts of ozone depletion on photosynthesis in the Southern Ocean, we need to know more about effects of ultraviolet radiation (UV) on phytoplankton in Antarctic waters, where, in addition to variable stratospheric ozone, temporal and regional differences in vertical mixing...
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Online Access: | http://hdl.handle.net/10222/26450 https://doi.org/10.4319/lo.1998.43.3.0433 |
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ftdalhouse:oai:DalSpace.library.dal.ca:10222/26450 2023-05-15T14:02:34+02:00 Inhibition of marine photosynthesis by ultraviolet radiation: Variable sensitivity of phytoplankton in the Weddell-Scotia Confluence during the austral spring Neale, PJ Cullen, JJ Davis, RF 2013-06-19T17:55:58Z http://hdl.handle.net/10222/26450 https://doi.org/10.4319/lo.1998.43.3.0433 unknown Limnology and Oceanography Neale, PJ, JJ Cullen, and RF Davis. 1998. "Inhibition of marine photosynthesis by ultraviolet radiation: Variable sensitivity of phytoplankton in the Weddell-Scotia Confluence during the austral spring." Limnology and Oceanography 43(3): 433-448. DOI:10.4319/lo.1998.43.3.0433 0024-3590 http://hdl.handle.net/10222/26450 http://dx.doi.org/10.4319/lo.1998.43.3.0433 43 3 433 article 2013 ftdalhouse https://doi.org/10.4319/lo.1998.43.3.0433 2021-12-29T18:08:42Z To assess the potential impacts of ozone depletion on photosynthesis in the Southern Ocean, we need to know more about effects of ultraviolet radiation (UV) on phytoplankton in Antarctic waters, where, in addition to variable stratospheric ozone, temporal and regional differences in vertical mixing might influence photosynthesis and photoacclimation of phytoplankton assemblages. Toward this end, we quantified the responses to UV of Antarctic phytoplankton in the Weddell-Scotia Confluence during the austral spring of 1993. Experimental results on spectral sensitivity of photosynthesis were fit statistically to a model-that incorporated uninhibited photosynthesis as a function of photosynthetically available radiation (PAR), wavelength-dependence of inhibition, and the kinetics of photosynthesis during exposure to UV. In contrast to previous results on UV-induced photoinhibition in a diatom culture at 20 degrees C, natural phytoplankton from open waters of the Antarctic showed no ability to counter UV-induced inhibition of photosynthesis during exposures of 0.5-4 h: the rate of photosynthesis declined exponentially as a function of cumulative exposure, and inhibition was not reversed during incubations for up to 3.5 h under benign conditions. The results suggest that nonlinear exposure-response relationships are necessary for modeling UV-dependent photosynthesis in the surface mixed layer of the springtime Weddell-Scotia Confluence. Consequently, we modified our laboratory-based model of photosynthesis and photoinhibition to describe photoinhibition as a nonlinear function of biologically weighted cumulative exposure to damaging irradiance. The model described similar to 90% of the spectrally dependent experimental variation in photosynthetic rate, and yielded six biological weighting functions (BWFs) for phytoplankton in the Weddell-Scotia Confluence. Assemblages from different stations showed substantial variability in sensitivity to UV. Tolerance of UV was generally highest in assemblages from shallower mixed layers, which presumably had experienced higher irradiance, including W, prior to sampling. The BWFs of assemblages that seemed acclimated to low irradiance showed the highest sensitivity to UV yet seen for Southern Ocean phytoplankton. The pattern of UV sensitivity was consistent with acclimation, but also with selection against less tolerant species. Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Dalhousie University: DalSpace Institutional Repository Antarctic Austral Southern Ocean The Antarctic Weddell Limnology and Oceanography 43 3 433 448 |
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Open Polar |
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Dalhousie University: DalSpace Institutional Repository |
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ftdalhouse |
language |
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description |
To assess the potential impacts of ozone depletion on photosynthesis in the Southern Ocean, we need to know more about effects of ultraviolet radiation (UV) on phytoplankton in Antarctic waters, where, in addition to variable stratospheric ozone, temporal and regional differences in vertical mixing might influence photosynthesis and photoacclimation of phytoplankton assemblages. Toward this end, we quantified the responses to UV of Antarctic phytoplankton in the Weddell-Scotia Confluence during the austral spring of 1993. Experimental results on spectral sensitivity of photosynthesis were fit statistically to a model-that incorporated uninhibited photosynthesis as a function of photosynthetically available radiation (PAR), wavelength-dependence of inhibition, and the kinetics of photosynthesis during exposure to UV. In contrast to previous results on UV-induced photoinhibition in a diatom culture at 20 degrees C, natural phytoplankton from open waters of the Antarctic showed no ability to counter UV-induced inhibition of photosynthesis during exposures of 0.5-4 h: the rate of photosynthesis declined exponentially as a function of cumulative exposure, and inhibition was not reversed during incubations for up to 3.5 h under benign conditions. The results suggest that nonlinear exposure-response relationships are necessary for modeling UV-dependent photosynthesis in the surface mixed layer of the springtime Weddell-Scotia Confluence. Consequently, we modified our laboratory-based model of photosynthesis and photoinhibition to describe photoinhibition as a nonlinear function of biologically weighted cumulative exposure to damaging irradiance. The model described similar to 90% of the spectrally dependent experimental variation in photosynthetic rate, and yielded six biological weighting functions (BWFs) for phytoplankton in the Weddell-Scotia Confluence. Assemblages from different stations showed substantial variability in sensitivity to UV. Tolerance of UV was generally highest in assemblages from shallower mixed layers, which presumably had experienced higher irradiance, including W, prior to sampling. The BWFs of assemblages that seemed acclimated to low irradiance showed the highest sensitivity to UV yet seen for Southern Ocean phytoplankton. The pattern of UV sensitivity was consistent with acclimation, but also with selection against less tolerant species. |
format |
Article in Journal/Newspaper |
author |
Neale, PJ Cullen, JJ Davis, RF |
spellingShingle |
Neale, PJ Cullen, JJ Davis, RF Inhibition of marine photosynthesis by ultraviolet radiation: Variable sensitivity of phytoplankton in the Weddell-Scotia Confluence during the austral spring |
author_facet |
Neale, PJ Cullen, JJ Davis, RF |
author_sort |
Neale, PJ |
title |
Inhibition of marine photosynthesis by ultraviolet radiation: Variable sensitivity of phytoplankton in the Weddell-Scotia Confluence during the austral spring |
title_short |
Inhibition of marine photosynthesis by ultraviolet radiation: Variable sensitivity of phytoplankton in the Weddell-Scotia Confluence during the austral spring |
title_full |
Inhibition of marine photosynthesis by ultraviolet radiation: Variable sensitivity of phytoplankton in the Weddell-Scotia Confluence during the austral spring |
title_fullStr |
Inhibition of marine photosynthesis by ultraviolet radiation: Variable sensitivity of phytoplankton in the Weddell-Scotia Confluence during the austral spring |
title_full_unstemmed |
Inhibition of marine photosynthesis by ultraviolet radiation: Variable sensitivity of phytoplankton in the Weddell-Scotia Confluence during the austral spring |
title_sort |
inhibition of marine photosynthesis by ultraviolet radiation: variable sensitivity of phytoplankton in the weddell-scotia confluence during the austral spring |
publishDate |
2013 |
url |
http://hdl.handle.net/10222/26450 https://doi.org/10.4319/lo.1998.43.3.0433 |
geographic |
Antarctic Austral Southern Ocean The Antarctic Weddell |
geographic_facet |
Antarctic Austral Southern Ocean The Antarctic Weddell |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_relation |
Limnology and Oceanography Neale, PJ, JJ Cullen, and RF Davis. 1998. "Inhibition of marine photosynthesis by ultraviolet radiation: Variable sensitivity of phytoplankton in the Weddell-Scotia Confluence during the austral spring." Limnology and Oceanography 43(3): 433-448. DOI:10.4319/lo.1998.43.3.0433 0024-3590 http://hdl.handle.net/10222/26450 http://dx.doi.org/10.4319/lo.1998.43.3.0433 43 3 433 |
op_doi |
https://doi.org/10.4319/lo.1998.43.3.0433 |
container_title |
Limnology and Oceanography |
container_volume |
43 |
container_issue |
3 |
container_start_page |
433 |
op_container_end_page |
448 |
_version_ |
1766272882447482880 |