Floating Ice-Algal Aggregates below Melting Arctic Sea Ice

Assmy, Philipp; Ehn, Jens K.; Fernández‐Méndez, Mar; Hop, Haakon; Katlein, Christian; Sundfjord, Arild; Bluhm, Katrin; Daase, Malin; Engel, Anja; Fransson, Agneta; Granskog, Mats A.; Hudson, Stephen R.; Kristiansen, Svein; Nicolaus, Marcel; Peeken, Ilka; Renner, Angelika; Spreen, Gunnar; Tatarek, Agnieszka; Wiktor, Józef

doi:10.1371/journal.pone.0076599

Cited by 108 publications

(100 citation statements)

References 60 publications

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“…One possible explanation is that the INPs were associated with melting sea ice. Materials such as algal aggregates, sea ice diatoms, and extracellular polymeric substances can be released into the ocean upon sea ice melting (Assmy et al, 2013;Boetius et al, 2015;Fernández-Méndez et al, 2014) and might be potential sources of the INPs observed in this study. Also interesting, a strong positive correlation was observed between salinity and bacterial abundance (R = 0.76, p = 0.039).…”

Section: Inps In the Microlayer And Bulk Seawatermentioning

confidence: 90%

Ice-nucleating particles in Canadian Arctic sea-surface microlayer and bulk seawater

et al. 2017

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Abstract. The sea-surface microlayer and bulk seawater can contain ice-nucleating particles (INPs) and these INPs can be emitted into the atmosphere. Our current understanding of the properties, concentrations, and spatial and temporal distributions of INPs in the microlayer and bulk seawater is limited. In this study we investigate the concentrations and properties of INPs in microlayer and bulk seawater samples collected in the Canadian Arctic during the summer of 2014. INPs were ubiquitous in the microlayer and bulk seawater with freezing temperatures in the immersion mode as high as −14 • C. A strong negative correlation (R = −0.7, p = 0.02) was observed between salinity and freezing temperatures (after correction for freezing depression by the salts). One possible explanation is that INPs were associated with melting sea ice. Heat and filtration treatments of the samples show that the INPs were likely heat-labile biological materials with sizes between 0.02 and 0.2 µm in diameter, consistent with previous measurements off the coast of North America and near Greenland in the Arctic. The concentrations of INPs in the microlayer and bulk seawater were consistent with previous measurements at several other locations off the coast of North America. However, our average microlayer concentration was lower than previous observations made near Greenland in the Arctic. This difference could not be explained by chlorophyll a concentrations derived from satellite measurements. In addition, previous studies found significant INP enrichment in the microlayer, relative to bulk seawater, which we did not observe in this study. While further studies are needed to understand these differences, we confirm that there is a source of INP in the microlayer and bulk seawater in the Canadian Arctic that may be important for atmospheric INP concentrations.

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Section: Inps In the Microlayer And Bulk Seawatermentioning

confidence: 90%

Ice-nucleating particles in Canadian Arctic sea-surface microlayer and bulk seawater

et al. 2017

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“…Primary production in the AO can comprise significant fractions that derive from ice algae (e.g., Tedesco et al, 2010Tedesco et al, , 2012Leu et al, 2015). During the Arctic melt season, floating ice algae aggregates likely play an important ecological role in an otherwise impoverished near-surface sea ice environment (Boetius et al, 2013;Assmy et al, 2014). The timing of phytoplankton and ice algae blooms as well as the biochemical composition is different.…”

Section: Confines and Limitationsmentioning

confidence: 99%

Physical constrains and productivity in the future Arctic Ocean

2015

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Today's physical oceanography and primary and secondary production was investigated for the entire Arctic Ocean (AO) with the physical-biologically coupled SINMOD model. To obtain indications on the effect of climate change in the twenty-first century the magnitude of change, and where and when these may take place SINMOD was forced with down-scaled climate trajectories of the International Panel of Climate Change with the A1B climate scenario which appears to predict an average global atmospheric temperature increase of 3.5-4 • C at the end of this century. It is projected that some surface water features of the physical oceanography in the AO and adjacent regions will change considerably. The largest changes will occur along the continuous domains of Pacific and in particular regarding Atlantic Water (AW) advection and the inflow shelves. Withdrawal of ice will increase primary production, but stratification will persist or, for the most, get stronger as a function of ice-melt and thermal warming along the inflow shelves. Thus, the nutrient dependent new and harvestable production will not increase proportionally with increasing photosynthetic active radiation (PAR). The greatest increases in primary production are found along the Eurasian perimeter of the AO (up to 40 g C m −2 y −1 ) and in particular in the northern Barents and Kara Seas (40-80 g C m −2 y −1 ) where less ice-cover implies less Arctic Water (ArW) and thus less stratification. Along the shelf break engirdling the AO upwelling and vertical mixing supplies nutrients to the euphotic zone when ice-cover withdraws northwards. The production of Arctic copepods along the Eurasian perimeter of the AO will increase significantly by the end of this century (2-4 g C m −2 y −1 ). Primary and secondary production will decrease along the southern sections of the continuous advection domains of Pacific and AW due to increasing thermal stratification. In the central AO primary production will not increase much due to stratification-induced nutrient limitation.

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“…25 producers. Taxonomic assessment of the diatom assemblage within several algal aggregates from Resolute Bay in the Canadian Arctic revealed a distinctive flora, characteristic of sea ice [26][27][28] . Thus, the three most abundant species were Navicula pelagica (ca.…”

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confidence: 99%

Source identification of the Arctic sea ice proxy IP25

et al. 2014

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Analysis of the organic geochemical biomarker IP 25 in marine sediments is an established method for carrying out palaeo sea ice reconstructions for the Arctic. Such reconstructions cover timescales from decades back to the early Pleistocene, and are critical for understanding past climate conditions on Earth and for informing climate prediction models. Key attributes of IP 25 include its strict association with Arctic sea ice together with its ubiquity and stability in underlying marine sediments; however, the sources of IP 25 have remained undetermined. Here we report the identification of IP 25 in three (or four) relatively minor (o5%) sea ice diatoms isolated from mixed assemblages collected from the Canadian Arctic. In contrast, IP 25 was absent in the dominant taxa. Chemical and taxonomical investigations suggest that the IP 25 -containing taxa represent the majority of producers and are distributed pan-Arctic, thus establishing the widespread applicability of the IP 25 proxy for palaeo Arctic sea ice reconstruction.

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Floating Ice-Algal Aggregates below Melting Arctic Sea Ice

Cited by 108 publications

References 60 publications

Ice-nucleating particles in Canadian Arctic sea-surface microlayer and bulk seawater

Ice-nucleating particles in Canadian Arctic sea-surface microlayer and bulk seawater

Physical constrains and productivity in the future Arctic Ocean

Source identification of the Arctic sea ice proxy IP25

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