Photophysiological responses of bottom sea-ice algae to fjord dynamics and rapid freshening
Sea ice algae have a broad salinity tolerance but can experience stress during rapid decreases in salinity that occur with seasonal ice melt and during ice sample melt. This study investigated the impact of salinity on the photophysiological responses of bottom-ice algal communities from two Svalbar...
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crfrontiers:10.3389/fmars.2023.1221639 2024-05-19T07:40:49+00:00 Photophysiological responses of bottom sea-ice algae to fjord dynamics and rapid freshening Forgereau, Zoé L. Lange, Benjamin A. Gradinger, Rolf Assmy, Philipp Osanen, Janina E. García, Laura M. Søreide, Janne E. Granskog, Mats A. Leu, Eva Campbell, Karley 2023 http://dx.doi.org/10.3389/fmars.2023.1221639 https://www.frontiersin.org/articles/10.3389/fmars.2023.1221639/full unknown Frontiers Media SA https://creativecommons.org/licenses/by/4.0/ Frontiers in Marine Science volume 10 ISSN 2296-7745 journal-article 2023 crfrontiers https://doi.org/10.3389/fmars.2023.1221639 2024-05-01T06:49:58Z Sea ice algae have a broad salinity tolerance but can experience stress during rapid decreases in salinity that occur with seasonal ice melt and during ice sample melt. This study investigated the impact of salinity on the photophysiological responses of bottom-ice algal communities from two Svalbard fjords (Tempelfjorden and Van Mijenfjorden). To further investigate the impact of salinity alone, and particularly to rapid freshening, the responses of a lab-cultured ice algal community from Van Mijenfjorden were assessed. Photophysiological responses were mainly determined via 14 C-based incubations which provided photosynthesis-irradiance curves. Main findings showed that i) the bottom-ice algal community in Tempelfjorden was characterized by lower photosynthetic efficiency and chlorophyll a biomass than the Van Mijenfjorden communities, and ii) a lab-cultured ice algal community from Van Mijenfjorden dominated by pennate diatoms had significantly lower photosynthetic efficiency, maximum photosynthesis and photoacclimation index after a decrease in salinity from 33 to 10. The lower photosynthetic efficiency and chlorophyll a biomass at Tempelfjorden may be attributed to the almost two-fold lower bulk-ice salinity in Tempelfjorden compared to Van Mijenfjorden, which was likely associated with freshwater inputs from the tidewater glacier Tunabreen during sea ice formation. Other factors such as under-ice light intensities, brine volume fraction and brine nutrient concentrations likely also contributed to variability in ice algal response. Furthermore, experimental results indicated that the cultured Van Mijenfjorden community was negatively impacted by a rapid (within 4 to 24 h) reduction in salinity from 33 to 10. We further documented a significant start of recovery of these algae after 168 h. From this work, we surmise that decreases in surface water salinity, for example arising from the intensifying freshening of fjord waters, may only cause temporary changes in ice algal photoacclimation state and thus in ... Article in Journal/Newspaper glacier ice algae Sea ice Svalbard Tempelfjord* Tempelfjorden Tidewater Van Mijenfjorden Frontiers (Publisher) Frontiers in Marine Science 10 |
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Frontiers (Publisher) |
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description |
Sea ice algae have a broad salinity tolerance but can experience stress during rapid decreases in salinity that occur with seasonal ice melt and during ice sample melt. This study investigated the impact of salinity on the photophysiological responses of bottom-ice algal communities from two Svalbard fjords (Tempelfjorden and Van Mijenfjorden). To further investigate the impact of salinity alone, and particularly to rapid freshening, the responses of a lab-cultured ice algal community from Van Mijenfjorden were assessed. Photophysiological responses were mainly determined via 14 C-based incubations which provided photosynthesis-irradiance curves. Main findings showed that i) the bottom-ice algal community in Tempelfjorden was characterized by lower photosynthetic efficiency and chlorophyll a biomass than the Van Mijenfjorden communities, and ii) a lab-cultured ice algal community from Van Mijenfjorden dominated by pennate diatoms had significantly lower photosynthetic efficiency, maximum photosynthesis and photoacclimation index after a decrease in salinity from 33 to 10. The lower photosynthetic efficiency and chlorophyll a biomass at Tempelfjorden may be attributed to the almost two-fold lower bulk-ice salinity in Tempelfjorden compared to Van Mijenfjorden, which was likely associated with freshwater inputs from the tidewater glacier Tunabreen during sea ice formation. Other factors such as under-ice light intensities, brine volume fraction and brine nutrient concentrations likely also contributed to variability in ice algal response. Furthermore, experimental results indicated that the cultured Van Mijenfjorden community was negatively impacted by a rapid (within 4 to 24 h) reduction in salinity from 33 to 10. We further documented a significant start of recovery of these algae after 168 h. From this work, we surmise that decreases in surface water salinity, for example arising from the intensifying freshening of fjord waters, may only cause temporary changes in ice algal photoacclimation state and thus in ... |
format |
Article in Journal/Newspaper |
author |
Forgereau, Zoé L. Lange, Benjamin A. Gradinger, Rolf Assmy, Philipp Osanen, Janina E. García, Laura M. Søreide, Janne E. Granskog, Mats A. Leu, Eva Campbell, Karley |
spellingShingle |
Forgereau, Zoé L. Lange, Benjamin A. Gradinger, Rolf Assmy, Philipp Osanen, Janina E. García, Laura M. Søreide, Janne E. Granskog, Mats A. Leu, Eva Campbell, Karley Photophysiological responses of bottom sea-ice algae to fjord dynamics and rapid freshening |
author_facet |
Forgereau, Zoé L. Lange, Benjamin A. Gradinger, Rolf Assmy, Philipp Osanen, Janina E. García, Laura M. Søreide, Janne E. Granskog, Mats A. Leu, Eva Campbell, Karley |
author_sort |
Forgereau, Zoé L. |
title |
Photophysiological responses of bottom sea-ice algae to fjord dynamics and rapid freshening |
title_short |
Photophysiological responses of bottom sea-ice algae to fjord dynamics and rapid freshening |
title_full |
Photophysiological responses of bottom sea-ice algae to fjord dynamics and rapid freshening |
title_fullStr |
Photophysiological responses of bottom sea-ice algae to fjord dynamics and rapid freshening |
title_full_unstemmed |
Photophysiological responses of bottom sea-ice algae to fjord dynamics and rapid freshening |
title_sort |
photophysiological responses of bottom sea-ice algae to fjord dynamics and rapid freshening |
publisher |
Frontiers Media SA |
publishDate |
2023 |
url |
http://dx.doi.org/10.3389/fmars.2023.1221639 https://www.frontiersin.org/articles/10.3389/fmars.2023.1221639/full |
genre |
glacier ice algae Sea ice Svalbard Tempelfjord* Tempelfjorden Tidewater Van Mijenfjorden |
genre_facet |
glacier ice algae Sea ice Svalbard Tempelfjord* Tempelfjorden Tidewater Van Mijenfjorden |
op_source |
Frontiers in Marine Science volume 10 ISSN 2296-7745 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3389/fmars.2023.1221639 |
container_title |
Frontiers in Marine Science |
container_volume |
10 |
_version_ |
1799480400998825984 |