Sea ice thermohaline dynamics and biogeochemistry in the Arctic Ocean: Empirical and model results

Duarte, Pedro; Meyer, Amélie; Olsen, Lasse Mork; Kauko, Hanna M.; Assmy, Philipp; Rösel, Anja; Itkin, Polona; Hudson, Stephen R.; Granskog, Mats A.; Gerland, Sebastian; Sundfjord, Arild; Steen, Harald B.; Hop, Haakon; Cohen, Lior; Peterson, Algot Kristoffer; Jeffery, Nicole; Elliott, Scott; Hunke, Elizabeth; Turner, Adrian K.

doi:10.1002/2016jg003660

Cited by 25 publications

(63 citation statements)

References 75 publications

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“…Unlike the ice algae, phytoplankton is being vertically mixed through the water column, reducing the probability of photoinhibition and increasing nutrient replenishment. Silicate limitation was possibly one important factor restricting growth in the thin ice, as indicated by biogeochemical modeling [ Duarte et al ., ]. Furthermore, in this particular case the water column bloom was dominated by Phaeocystis pouchetii which is a very plastic species with regard to photoacclimation, suggesting that it can acclimate to the alternating light field provided by the heterogenous ice cover [ Assmy et al ., ].…”

Section: Discussionmentioning

confidence: 99%

Windows in Arctic sea ice: Light transmission and ice algae in a refrozen lead

et al. 2017

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The Arctic Ocean is rapidly changing from thicker multiyear to thinner first‐year ice cover, with significant consequences for radiative transfer through the ice pack and light availability for algal growth. A thinner, more dynamic ice cover will possibly result in more frequent leads, covered by newly formed ice with little snow cover. We studied a refrozen lead (≤0.27 m ice) in drifting pack ice north of Svalbard (80.5–81.8°N) in May–June 2015 during the Norwegian young sea ICE expedition (N‐ICE2015). We measured downwelling incident and ice‐transmitted spectral irradiance, and colored dissolved organic matter (CDOM), particle absorption, ultraviolet (UV)‐protecting mycosporine‐like amino acids (MAAs), and chlorophyll a (Chl a) in melted sea ice samples. We found occasionally very high MAA concentrations (up to 39 mg m−3, mean 4.5 ± 7.8 mg m−3) and MAA to Chl a ratios (up to 6.3, mean 1.2 ± 1.3). Disagreement in modeled and observed transmittance in the UV range let us conclude that MAA signatures in CDOM absorption spectra may be artifacts due to osmotic shock during ice melting. Although observed PAR (photosynthetically active radiation) transmittance through the thin ice was significantly higher than that of the adjacent thicker ice with deep snow cover, ice algal standing stocks were low (≤2.31 mg Chl a m−2) and similar to the adjacent ice. Ice algal accumulation in the lead was possibly delayed by the low inoculum and the time needed for photoacclimation to the high‐light environment. However, leads are important for phytoplankton growth by acting like windows into the water column.

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Section: Discussionmentioning

confidence: 99%

Windows in Arctic sea ice: Light transmission and ice algae in a refrozen lead

et al. 2017

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“…The collected time series on sea‐ice physics and biogeochemistry further provided an opportunity to evaluate a state of the art sea‐ice numerical model (Duarte et al, ), showing that physics can be well reproduced given the forcing is realistic, and also giving insights into ice algae dynamics in different types of sea ice. A unique time series quantified the factors that affect surface water CO 2 , showing the importance of transient storm events and ice dynamics for ocean‐atmosphere CO 2 exchange in ice‐covered waters (Fransson et al, ).…”

Section: Overview Of Conditions During Experiments and Main Findingsmentioning

confidence: 99%

Atmosphere‐Ice‐Ocean‐Ecosystem Processes in a Thinner Arctic Sea Ice Regime: The Norwegian Young Sea ICE (N‐ICE2015) Expedition

et al. 2018

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Arctic sea ice has been in rapid decline the last decade and the Norwegian young sea ICE (N‐ICE2015) expedition sought to investigate key processes in a thin Arctic sea ice regime, with emphasis on atmosphere‐snow‐ice‐ocean dynamics and sea ice associated ecosystem. The main findings from a half‐year long campaign are collected into this special section spanning the Journal of Geophysical Research: Atmospheres, Journal of Geophysical Research: Oceans, and Journal of Geophysical Research: Biogeosciences and provide a basis for a better understanding of processes in a thin sea ice regime in the high Arctic. All data from the campaign are made freely available to the research community.

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“…They may survive only in the bottom layers (Kottmeier and Sullivan, 1987), where relatively high abundances have been observed in early spring in Arctic landfast ice (Figure 3a). In the ice interior, however, centric diatoms observed in high abundance in young pack ice (Figure 3d) apparently disappear from the ice column over time (Gleitz et al, 1998;Ratkova and Wassmann, 2006;Olsen et al, 2017). Heterotrophic protists are present throughout the year in pack ice (Figure 3f).…”

Section: Seasonal Variationmentioning

confidence: 99%

Microalgal community structure and primary production in Arctic and Antarctic sea ice: A synthesis

Leeuwe

Tedesco

Arrigo

et al. 2018

Elementa: Science of the Anthropocene

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van Leeuwe, MA, et al. 2018 Microalgal community structure and primary production in Arctic and Antarctic sea ice: A synthesis. Elem Sci Anth, 6: 4. DOI: https://doi.org/10.1525/elementa.267 IntroductionSea ice is one of the largest biomes on earth. The area covered by Arctic (15.6 × 10 6 km 2 ) and Antarctic (18.8 × 10 6 km 2 ) sea ice is roughly 4 and 5% of the global ocean surface (361.9 × 10 6 km 2 ) at their respective maximum extents (Meier, 2017;Stammerjohn and Maksym, 2017). Sea ice is a very diverse and potentially very productive habitat, with primary production estimated to amount to 2-24% of total production in sea-ice covered marine areas (Arrigo, 2017). Sea ice is especially productive in spring and summer when, locally, carbon biomass can be ten times higher in the bottom ice than in the seawater, with values greater than 3 mg chlorophyll a) in bottom layers (e.g., Corneau et al., 2013). On some occasions, ice algae may contribute up to 50-60% of total primary production McMinn et al., 2010; Fernandez-Mendez et al., 2015). Sympagic (ice-associated) microalgae (see Horner et al., 1992, for terminology) are REVIEWMicroalgal community structure and primary production in Arctic and Antarctic sea ice: A synthesis Sea ice is one the largest biomes on earth, yet it is poorly described by biogeochemical and climate models. In this paper, published and unpublished data on sympagic (ice-associated) algal biodiversity and productivity have been compiled from more than 300 sea-ice cores and organized into a systematic framework. Significant patterns in microalgal community structure emerged from this framework. Autotrophic flagellates characterize surface communities, interior communities consist of mixed microalgal populations and pennate diatoms dominate bottom communities. There is overlap between landfast and pack-ice communities, which supports the hypothesis that sympagic microalgae originate from the pelagic environment. Distribution in the Arctic is sometimes quite different compared to the Antarctic. This difference may be related to the time of sampling or lack of dedicated studies. Seasonality has a significant impact on species distribution, with a potentially greater role for flagellates and centric diatoms in early spring. The role of sea-ice algae in seeding pelagic blooms remains uncertain. Photosynthesis in sea ice is mainly controlled by environmental factors on a small scale and therefore cannot be linked to specific ice types. Overall, sea-ice communities show a high capacity for photoacclimation but low maximum productivity compared to pelagic phytoplankton. Low carbon assimilation rates probably result from adaptation to extreme conditions of reduced light and temperature in winter. We hypothesize that in the near future, bottom communities will develop earlier in the season and develop more biomass over a shorter period of time as light penetration increases due to the thinning of sea ice. The Arctic is already witnessing changes. The shift forward in time of the algal bloom can resu...

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Sea ice thermohaline dynamics and biogeochemistry in the Arctic Ocean: Empirical and model results

Cited by 25 publications

References 75 publications

Windows in Arctic sea ice: Light transmission and ice algae in a refrozen lead

Windows in Arctic sea ice: Light transmission and ice algae in a refrozen lead

Atmosphere‐Ice‐Ocean‐Ecosystem Processes in a Thinner Arctic Sea Ice Regime: The Norwegian Young Sea ICE (N‐ICE2015) Expedition

Microalgal community structure and primary production in Arctic and Antarctic sea ice: A synthesis

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