Abstract
Sea ice primary production is a key component supplying carbon to higher trophic levels when few other resources are available. In bottom-ice habitats, this production is limited by light availability and nutrient supply from underlying seawater. Reports of low sea ice primary production from Greenland have reinforced the view that landfast ice is regionally unimportant. Here, we document a single early-spring observation of intense algal production in sea ice adjacent to marine terminating glaciers in West Greenland, an environment rarely examined in ice studies. The bloom included abundant pennate diatoms, including Nitzschia frigida, and reached a daily primary production of 146 ± 4.8 mg C m⁻² d⁻¹ and biomass accumulation of 42.4 ± 1.6 mg Chlorophyll a (Chl a) m⁻², exceeding previous Greenland observations. A biomass-specific production of 3.40 mg C mg Chl a⁻¹ d⁻¹ and maximum quantum yield (ΦPSII_max) of 0.44 indicated an active community. Strong silicic acid depletion in the presence of significant nitrate and phosphate concentrations suggested that silicic acid was the primary limiting nutrient within the ice. We propose that inflow-driven fjord circulation likely enhanced nutrient availability beneath the ice, while turbulence-driven fluxes across the ice-ocean interface represent a plausible mechanism for sustaining the observed high sympagic production during this sampling event. Sea ice in fjords with marine-terminating glaciers may therefore support high early-season production under favorable local conditions.
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Ackowledgements
Pedro Duarte participation in this study was supported by the Centre for ice, Cryosphere, Carbon and Climate (iC3) financed by the Research Council of Norway through its Centers of Excellence funding scheme (project number 332635) and by project BREATHE (Bottom sea ice Respiration and nutrient Exchanges Assessed for THE Arctic) funded by the Research Council of Norway (grant no. 325405).
Funding
The project was funded by Aarhus University Research Foundation Project nr. 84537 with additional support from the Danish Council for Independent Research (Project 3103-00253B, “Ice Algae Photon Harvesting at Polar First Light”). We gratefully acknowledge the contributions of the Danish National Research Foundation (DNRF 185) to the Center for Ice-Free Arctic Research (CIFAR), Aarhus University. D.H.S received financial support from the Greenland Climate Research Centre (GCRC), Greenland Institute of Natural Resources and from the Arctic Research Centre of Aarhus University.
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Søgaard, D.H., Rysgaard, S., Vonnahme, T.R. et al. High sea ice algal primary production near marine-terminating glaciers linked to turbulence-driven nutrient fluxes across the ice–ocean interface.
Sci Rep (2026). https://doi.org/10.1038/s41598-026-53846-0
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DOI: https://doi.org/10.1038/s41598-026-53846-0
Keywords
- Sea ice algae
- Turbulent nutrient exchange
- Silicic acid limitation
- Marine-terminating glaciers
- Greenland fjords
- Arctic ecosystems
Source: Ecology - nature.com
