Incorporated platelet ice layers provide refuge for sea-ice algae in the Kong Hakon VII Hav
Lenss, M.; Moreau, S.; Chierici, M.; Claeys, P.; Fransson, A.; Gerland, S.; Itkin, P.; Osanen, J.E.; Rozanska-Pluta, M.; Salganik, E.; Wiktor, J.; Campbell, K. (2025). Incorporated platelet ice layers provide refuge for sea-ice algae in the Kong Hakon VII Hav. Mar. Ecol. Prog. Ser. 774: 143-164. https://dx.doi.org/10.3354/meps14979
In: Marine Ecology Progress Series. Inter-Research: Oldendorf/Luhe. ISSN 0171-8630; e-ISSN 1616-1599, more
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| Author keywords |
Platelet ice;Sea-ice algae;Southern Ocean;Nutrients;Berkeleya adeliensis;terra-nova bay;weddell sea;mcmurdo sound;ross sea;phytoplankton growth;stable-isotopes;organic-matter;chlorophyll-a;dynamics;landfast |
| Authors | | Top |
- Lenss, M.
- Moreau, S.
- Chierici, M.
- Claeys, P., more
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- Fransson, A.
- Gerland, S.
- Itkin, P.
- Osanen, J.E.
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- Rozanska-Pluta, M.
- Salganik, E.
- Wiktor, J.
- Campbell, K.
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| Abstract |
In this study, we document layers of incorporated platelet ice up to 0.81 m thick in broken-out landfast ice for the first time in the Kong Hakon VII Hav, Southern Ocean. Sampling occurred in January 2022, when sea ice was highly porous (average brine volume > 10%) and actively melting. Chlorophyll a (chl a) concentrations were significantly higher (Mann-Whitney U-test, U = 154, p = 0.072) in bottom-incorporated platelet ice layers in comparison to neighboring layers of other textures. The maximum chl a concentration (191.80 mu g l(-1)) was observed in bottom-incorporated platelet ice and dominated by the pennate diatom Berkeleya adeliensis. Due to biological uptake, mean (+/- SD) bulk concentrations of nitrate (0.48 +/- 0.26 mu mol l(-1)) and phosphate (0.15 +/- 0.2 mu mol l(-1)) were low for summertime sea ice in the Southern Ocean, but biological enrichment of nitrite was observed throughout the ice column. Sea-ice texture was likely a relevant driver of the biological and biogeochemical properties observed in this study due to its impact on habitable pore space and brine-scale nutrient dynamics; however, specifically differentiating between effects due to depth versus those due to texture was beyond the scope of this study. The ice floes sampled here were some of the last to melt in the summer, suggesting that bottom-incorporated platelet ice layers may serve as a final refugium for sea-ice algae before the seasonal minimum in sea-ice extent. This refugium effect could become increasingly important under future warming scenarios, in which summertime conditions are expected to occur earlier and/or persist longer. |
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