Ikaite crystal distribution in winter sea ice and implications for CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; system dynamics

Rysgaard, Søren; Søgaard, Dorte Haubjerg; Cooper, M.; Pućko, Monika; Lennert, Kunuk; Papakyriakou, Tim; Wang, Fei; Geilfus, Nicolas-Xavier; Glud, Ronnie N.; Ehn, Jens K.; Mcginnis, Daniel Frank; Attard, Karl M.; Sievers, J.; Deming, Jody W.; Barber, David G.

doi:10.5194/tc-7-707-2013

Cited by 91 publications

(153 citation statements)

References 45 publications

(46 reference statements)

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“…At Station Nord, the mean TA:DIC ratio is less than one in both first-and multi-year sea ice (0.7 and 0.9, respectively) and generally increases with depth, but ikaite concentration generally decreases with depth and were 335 lower than in first-year sea ice at Cambridge Bay, SERF, and in previous studies (e.g., Geilfus et al, 2013a;Rysgaard et al, 2013). The low TA and DIC concentrations observed at Station Nord, combined with the low bulk salinity, are not conducive to ikaite precipitation, hence the low ikaite concentrations observed in both first and multi-year sea ice.…”

Section: Relationship Between Ikaite and Environmental Datamentioning

confidence: 93%

Quantification of calcium carbonate (ikaite) in first– and multi–year sea ice

Kyle

Rysgaard

Wang

et al. 2017

Preprint

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Ikaite (CaCO 3 •6H 2 O) is a metastable calcium carbonate mineral that forms at low temperature and/or high pressure. 20Ikaite precipitates in sea ice and may play a significant role in air-sea CO 2 exchange in ice covered seas and oceans.However, the spatial and temporal dynamics of ikaite in sea ice are poorly understood due to few available measurements and time consuming analytical techniques. Here, we present a new method for quantifying ikaite in sea ice and compare it with a more time-consuming imaging technique currently in use. In short, sea ice cores were melted at low temperatures (<4°C), filtered for ikaite crystals that subsequently were dissolved and analyzed as 25 dissolved inorganic carbon (DIC). The new method was applied on cores from experimental sea ice in Winnipeg ice algae were present. The higher abundance of ikaite in young first-year sea ice indicates that its concentrations will likely increase in the Arctic as a result of the recent rapid decline of the multi-year ice cover and increasing presence of seasonal sea ice. As a result, it is likely that ikaite will play a more significant role in air-sea CO 2 exchange in ice-covered seas in the future.

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Section: Relationship Between Ikaite and Environmental Datamentioning

confidence: 93%

Quantification of calcium carbonate (ikaite) in first– and multi–year sea ice

Kyle

Rysgaard

Wang

et al. 2017

Preprint

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“…2004; Nomura et al, 2006;Papadimitriou et al, 2004;Rysgaard et al, 2007Rysgaard et al, , 2011Rysgaard et al, , 2012Rysgaard et al, , 2013.…”

Section: Introductionunclassified

“…the formation/dissolution of calcium carbonate (CaCO 3 · 6 H 2 O) within brine (Dieckmann et al, 2008;Fischer et al, 2013;Marion, 2001;Papadimitriou et al, 2004;Rysgaard et al, 2013), which leads to an increase/decrease in brine pCO 2 , thus changing the potential for CO 2 exchanges at the ice surface (Geilfus et al, 2012;Miller et al, 2011b;Sogaard et al, 2013); 3. CaCO 3 · 6 H 2 O being observed in brine-soaked snow at the snow-ice interface Nomura et al, 2013).…”

Section: Thermochemical Carbon Processes In the Icementioning

confidence: 99%

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Winter observations of CO<sub>2</sub> exchange between sea ice and the atmosphere in a coastal fjord environment

et al. 2015

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Abstract. Eddy covariance observations of CO 2 fluxes were conducted during March-April 2012 in a temporally sequential order for 8, 4 and 30 days, respectively, at three locations on fast sea ice and on newly formed polynya ice in a coastal fjord environment in northeast Greenland. CO 2 fluxes at the sites characterized by fast sea ice (ICEI and DNB) were found to increasingly reflect periods of strong outgassing in accordance with the progression of springtime warming and the occurrence of strong wind events: F ICE1 CO 2 = 1.73 ± 5 mmol m −2 day −1 and F DNB CO 2 = 8.64 ± 39.64 mmol m −2 day −1 , while CO 2 fluxes at the polynya site (POLYI) were found to generally reflect uptake F POLY1 CO 2 = −9.97 ± 19.8 mmol m −2 day −1 . Values given are the mean and standard deviation, and negative/positive values indicate uptake/outgassing, respectively. A diurnal correlation analysis supports a significant connection between site energetics and CO 2 fluxes linked to a number of possible thermally driven processes, which are thought to change the pCO 2 gradient at the snow-ice interface. The relative influence of these processes on atmospheric exchanges likely depends on the thickness of the ice. Specifically, the study indicates a predominant influence of brine volume expansion/contraction, brine dissolution/concentration and calcium carbonate formation/dissolution at sites characterized by a thick sea-ice cover, such that surface warming leads to an uptake of CO 2 and vice versa, while convective overturning within the sea-ice brines dominate at sites characterized by comparatively thin sea-ice cover, such that nighttime surface cooling leads to an uptake of CO 2 to the extent permitted by simultaneous formation of superimposed ice in the lower snow column.

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“…A2c). Increasing TA at higher salinities and nearly constant DIC concentrations has been observed before in Arctic and Antarctic regions (Dieckmann et al, 2008;Fransson et al, 2011;Rysgaard et al, 2012;Shadwick et al, 2014;Legge et al, 2015) and may be due to formation of ikaite crystals (CaCO 3 6H 2 O; Suess et al, 1982) that store TA in sea ice and, upon melting, release the excess TA into the surface water (Rysgaard et al, 2012(Rysgaard et al, , 2013. However, reasons for the observed increasing TA at higher salinities along the WAP remain speculative, since direct evidence of ikaite formation/dissolution such as an increase in DIC associated with TA increase is missing (Fig.…”

Section: Parametermentioning

confidence: 99%

Two decades of inorganic carbon dynamics along the West Antarctic Peninsula

et al. 2015

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Abstract. We present 20 years of seawater inorganic carbon measurements collected along the western shelf and slope of the Antarctic Peninsula. Water column observations from summertime cruises and seasonal surface underway pCO 2 measurements provide unique insights into the spatial, seasonal, and interannual variability in this dynamic system. Discrete measurements from depths > 2000 m align well with World Ocean Circulation Experiment observations across the time series and underline the consistency of the data set. Surface total alkalinity and dissolved inorganic carbon data showed large spatial gradients, with a concomitant wide range of arag (< 1 up to 3.9). This spatial variability was mainly driven by increasing influence of biological productivity towards the southern end of the sampling grid and meltwater input along the coast towards the northern end. Large inorganic carbon drawdown through biological production in summer caused high near-shore arag despite glacial and seaice meltwater input. In support of previous studies, we observed Redfield behavior of regional C / N nutrient utilization, while the C / P (80.5 ± 2.5) and N / P (11.7 ± 0.3) molar ratios were significantly lower than the Redfield elemental stoichiometric values. Seasonal salinity-based predictions of arag suggest that surface waters remained mostly supersaturated with regard to aragonite throughout the study. However, more than 20 % of the predictions for winters and springs between 1999 and 2013 resulted in arag < 1.2. Such low levels of arag may have implications for important organisms such as pteropods. Even though we did not detect any statistically significant long-term trends, the combination of ongoing ocean acidification and freshwater input may soon induce more unfavorable conditions than the ecosystem experiences today.

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Ikaite crystal distribution in winter sea ice and implications for CO<sub>2</sub> system dynamics

Cited by 91 publications

References 45 publications

Quantification of calcium carbonate (ikaite) in first– and multi–year sea ice

Quantification of calcium carbonate (ikaite) in first– and multi–year sea ice

Winter observations of CO<sub>2</sub> exchange between sea ice and the atmosphere in a coastal fjord environment

Two decades of inorganic carbon dynamics along the West Antarctic Peninsula

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Ikaite crystal distribution in winter sea ice and implications for CO&lt;sub&gt;2&lt;/sub&gt; system dynamics

Cited by 91 publications

References 45 publications

Quantification of calcium carbonate (ikaite) in first– and multi–year sea ice

Quantification of calcium carbonate (ikaite) in first– and multi–year sea ice

Winter observations of CO&lt;sub&gt;2&lt;/sub&gt; exchange between sea ice and the atmosphere in a coastal fjord environment

Two decades of inorganic carbon dynamics along the West Antarctic Peninsula

Contact Info

Product

Resources

About

Ikaite crystal distribution in winter sea ice and implications for CO<sub>2</sub> system dynamics

Winter observations of CO<sub>2</sub> exchange between sea ice and the atmosphere in a coastal fjord environment