Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , 2 ´ elie, precipi- 3 Rysgaard usion and ; ff ). However, Terre Ad within sea ice. Anderson and ff Discussions ; , L. Norman 3 2006 ect di 4 2001 , ff , The Cryosphere 1981 , during precipitation in precipitation in sea ice was predicted to occur Delille ). On the basis of ther- 2 3 3 ; ¨ Marion ottlicher CO 2011 p 2002 , , , J. G 1 , Salinity, DOC, DON, Phosphate, and Jones and Coote uptake by the ocean. However, little is 3 ; 2 Tison et al. Loose et al. ; , G. Nehrke 1 506 505 1 1937 , 2011 , , A. Krell 2,3 Gitterman during dissolution in spring. CaCO 2 Miller et al. ; CO p 2011 , , and G. S. Dieckmann 5 ). The physical barrier itself has a major impact on the gas exchange be- , D. N. Thomas 2009 ) and it was proposed to precipitate as calcite ( , 1,6 2010 , 1985 2007 , , This discussion paper is/has been under review for the journal The Cryosphere (TC). Please refer to the corresponding final paper in TC if available. Alfred Wegener Institute for Polar andOcean Marine Sciences, Reserach, College Bremerhaven, of Germany NaturalMarine Sciences, Centre, Bangor Finnish University, Menai Environment Bridge, Institute UK Institute (SYKE), of Helsinki, Synchrotron Finland Radiation (ISS), Synchrotron Radiation Source ANKA, USR3278, CRIOBE, CNRS-EPHE, Perpignan, France Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany Comiso in natural sea iceJones formation ( et al. modynamic equilibrium calculations, the precipitation of CaCO tween atmosphere and ocean, and recentlyhow the physical discussion and has biogeochemical extended processes to within considering flux the of ice gases itself to can both a atmosphere and ocean ( Sea ice covers up to( 7 % of the total surface area of the oceans at its maximum extent represents a contribution betweenoceans. 0.12 and The 9 Tg horizontal Cfound distribution the to precipitate of the in annual ikaite the carbon snow in on flux sea top in ice of polar the was sea heterogenous. ice. 1 We also Introduction This is the first quantitative studydiscusses of its hydrous calcium potential carbonate, significance as for ikaite,brine the in samples sea carbon were ice cycle collected and in fromDecember polar pack 2007 oceans. and during land Ice an fast cores expedition sea in and Antarctica. ice the between East Samples September Antarctic were and and analysed anothertotal o for alkalinity. CaCO A relationshiptation between could the not measured be parameters observed.layer and of We sea CaCO found ice calcium with carbonate, values as up ikaite, to mostly 126 in mg the ikaite top per liter melted sea ice. This potentially Calcium carbonate precipitation inwinter sea and decrease ice canis increase thought to potentiallyknown drive about the significant quantitative CO spatial and temporal distribution of CaCO Abstract 1 2 3 4 Karlsruhe Institute of5 Technology, Eggenstein-Leopoldshafen, Germany 6 Received: 18 January 2012 – Accepted:Correspondence 25 to: January 2012 M. – Fischer Published: (michael.fi[email protected]) 3 FebruaryPublished 2012 by Copernicus Publications on behalf of the European Geosciences Union. The Cryosphere Discuss., 6, 505–530,www.the-cryosphere-discuss.net/6/505/2012/ 2012 doi:10.5194/tcd-6-505-2012 © Author(s) 2012. CC Attribution 3.0 License. C. Riaux-Gobin Quantification of ikaite in Antarctic seaM. Fischer ice 5 25 20 15 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , , 3 Dieck- E near 00 5 0 Sala et al. 00 ◦ Papadimitriou Norman et al. ; erent degrees of ff erent locations be- S 140 1998 ff 00 , van der Merwe et al. ). 13 0 ) found calcium carbonate 39 1988 , ◦ 2008 ( Killawee et al. ) showed that with brine, dissolved east (Fig. 1). The cores were cut into ). Simulations of the chemistry occurring 2009 ◦ , precipitation in sea ice could drive significant 508 507 Zullig and Morse 2010 3 ; ). Six complete ice cores (D1 to D6) were taken , 2007 ( and 128 Dieckmann et al. precipitation in Antarctic sea ice on a spatial and ◦ 1993 2007 3 3 month, Anne Jacquet, personal communication) ( , ≈ ). A general description of the ice conditions during the ) until et al. ff 2011 ( 2002 , levels found below sea ice to calcium carbonate precipitation. Delille et al. 2 Rysgaard et al. Sander and Morin O in Antarctic sea ice, and more recently in Arctic sea ice ( 2 south and 116 ; Bischo CO ◦ ). ) also claim that CaCO 6H p · 3 2006 , 2010 2007 Tison et al. ( , Meiners et al. ; and 66 ◦ 2004 ) and ). ). However, to date most studies of calcium carbonate in sea ice have been mainly uptake by the ocean and therefore contribute significantly to a polar carbon pump. , 2 On the second campaign (from November to December 2007) sea ice samples were The objective of this study therefore was to: (1) Provide the first systematic obser- Besides its function as a component in the carbon cycle, the mineral is also thought 2009 Sander et al. calcium carbonate, we chose an area 50 m away from the first sampling site. On this 10 cm sections within a fewcores minutes from after station sampling S1 and stored todeformation in S4 plastic (Table and 1). containers. S6 Ice to The S14grounded ice represent icebergs. core pack ice from Further with station di details S5 was on taken ice from types, fast see ice Table between 1, isolated patches of snowand being stored present. as The described coresof above. ikaite, were In we also also order cut collected to four into(Table surface 1). determine 10 cores cm small-scale Cores (D7 sections D7 to vertical D10) and distribution on between D9 10 top, were and while taken 15 cm from D8 length from the was main older taken sampling fast next site ice to withoutwas approximately it any taken 200 snow from m and sea away included ice from snow.formation, which the in had Ice main contrast formed sample sampling to in D10 cores site. autumnwere was and D1–D9 cut This had which taken into core remained were 2 intact from cm since younger sections. its sea ice. In These addition, cores to determine horizontal spatial variability of Two campaigns were performed between Septemberfirst and campaign December (Sea 2007. During IceAurora the Australis) Physics fourteen and ice Ecosystemtween cores eXperiment 64 (S1 (SIPEX) to S14) onboard were RSV taken at di collected close to thestation C French described base in Dumontfrom d’Urville, young 66 fast seawhich ice had (age: formed in August. This area was predominantly free of snow with only 2 Methods ( expedition can be found instations Worby et (see Table al. 2) (2011). was collected Brine for from nutrient sackholes and from DOM 10 analyses out (see of 14 2011 ikaite in firn ice300 km of away, the may Antarctic also continent, have which implications appears for to its be use derived as from a sea sea ice ice proxy ( in polar regionsof over inert recently formed sea-saltcalcium sea bromide carbonate ice to from relate reactive freezing the bromine sea ODE monoxide water (BrO) to is when the taken precipitation transformation into of account. The discoveryqualitative of and littlewithin is sea known ice. aboutikaite the There precipitation is spatial as also and well ais temporal as that lack distribution phosphate on of and the of knowledge dissolvedcalcium amount on organic CaCO carbonate matter and the ( (DOM) fate exact may conditions of reduce leading the ikaite: precipitation to e.g. of onevation and assumption quantification oftemporal CaCO scale and (2) tokalinity, phosphate, investigate and relationships dissolved between organic calcium matter. carbonate and al- 2008 Delille et al. CO to have a key( role in tropospheric ozone depletion events (ODEs) at high latitudes et al. as ikaite CaCO mann et al. organic carbon (DIC) isascribe rejected the from growing high sea ice to the underlying waters. They actual evidence was, for a long time, only indirect ( 5 5 25 15 20 10 15 25 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , C ◦ Kroon Hanson C( ◦ O a conven- 2 6H Dieckmann et al. · 3 direction) in a grid of was added to disso- ) and of dissolved in- − 2 3 raction (µ-XRD) under y ff ). and x 2010 ( ), nitrite (NO − 3 C for later mineralogical phase iden- ◦ 18 − 509 510 Nomura et al. C to avoid decomposition of the mineral ikaite. Regular ◦ ). Dissolved organic nitrogen was determined by subtraction C. The melt water was filtered through 0.2 µm polycarbonate ◦ , for methods). These were briefly inspected under the binocular 1996 ( ) as adapted for flow injection analysis (FIA) on a LACHAT Instru- from the total dissolved nitrogen (TDN) analyzed using on-line per- 2008 10 m to minimize bias from spatial heterogeneity. The partial ice core , + 4 × ). 1983 , ff 2009 , erent vials for total alkalinity (TA), dissolved organic carnon (DOC), dissolved , and NH ff − 3 ). ). Total alkalinity (D-SH1 to D-SH7) was measured at the station laboratory within Qian and Mopper Mineral phase identification was conducted by micro X-ray di To quantify the amount of ikaite within the sample, the quantity of calcium ions were Brines from sackholes (D-SH1 to D-SH7 and from 10 stations during the SIPEX For the spatial analyses of the horizontal distribution of CaCO We also sampled glacial firn ice 6 km away from the ice shelfAll at sea Prud’homme ice samples to were slowly melted in a climate controlled room where the tem- Sarma 2008 and Korole ments Quick-Chem 8000 autoanalyzer (Haleswas analysed et by al., high 2004). temperature combustionto Dissolved on an organic MQ1000 carbon TOC analyzer according of NO oxodisulfate oxidation coupled with ultraviolet radiation at pH 9.0 and 100 cryogenic conditions on selectedmental samples Studies at SUL-X the at Synchrotron theKarlsruhe synchrotron Laboratory (now radiation for source Kalsruhe Environ- ANKA, Institute Forschungszentrum of Technology) as described by nitrogen (DON), dissolved organic carbonthe major (DOC) dissolved and inorganic alkalinity nutrients, nitrate (Tableorganic 2). (NO phosphorus (DIP) Analysis was for done using standard colorimetric methodology ( ( determined using Inductively-CoupledOES). Plasma The plastic Optical caps Emission containingthe the content Spectrometry filter was were transferred (ICP to rinsed largeruntil with vials. concentrated all The ethanol the transferred and samples ethanol were hadciate dried all evaporated. at molecules 60 Five before ml theikaite concentrated samples was HNO were calculated analysed based in on the the measured ICP calcium. OES. Thecampaign) amount of were analyzed for in situ concentrations of phosphate, dissolved organic 1993 one day after sampling as described by tional geostatistical spatial interpolation was applied( by using the simple kriging method microscope and photographed to check theas morphology described and above. subsequently also filtered ter never rose abovefilters 0 and the volume determined.vial The filters containing with 75 crystals % were ethanoltification then placed and and in quantitative frozen a measurements. plastic at after In swirling several the instances melted crystals samplesThe were and crystals collected allowing were crystals transferred to fromDieckmann settle the et in al. vortex the to resulting a vortex. petri dish using a glass pipette (see containers and brought to the base laboratory. peratures never exceeded 4 monitoring (several times athe day) cores, guaranteed or a sections processing were of melted. the This samples ensured as that soon the as temperature of the melt wa- allowed to collect in theinto sackholes di and sampled withorganic a nitrogen vacuum (DON), pump and andwere filtered transferred phosphate through 0.2 analyses. µm cellulose6 acetate months. filter Samples and The for kept TA frozen samples DOM until were analyses and measured within directly nutrients in thetest base if laboratory. calcium carbonates(1 are m) found was on collected the and cut ice into shelf 3 in equal this sections. region. The One sections surface were core stored in plastic 20 m by 20 m (D-SP1in to clean D-SP25, plastic Table containers. 1).30 At cm The the were partial main cored ice sampling every cores two site,an obtained or area sackholes were three of (D-SH1 days stored 10 to m for D-SH7) aobtained of temporal from analysis these of sackholes brine was and also ice stored from in clean plastic containers. Brine was site the first top 10 cm of fast ice were sampled every 5 m ( 5 5 15 20 10 25 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 1 er − ff 35) = S . Below 1 − ) indicate, that Wettlaufer and melted sea ice, . TA did not show 1 1 − − 2008 ) dissolved organic , 2009 , ) concentrations in the brines (ikaite saturation state of sea- ´ 35 elie were of a similar magnitude . Ice texture analyses of cores S3 ikaite 1 − Ω Dieckmann et al. at the beginning, it did not increase Terre Ad 35 ff ). Although we were not able to verify the , Fig. 8, Table 2). Hence, we could not di 512 511 1 shows a trend which might indicate biological Papadimitriou et al. − 3 2010 , and DOC 35 O in sea ice is already heterogenous. 2 6H · melted sea ice. The maximum amount of ikaite was found 3 1 − melted sea ice) was observed at the snow/ice interface. Salinity 1 − ) and dissolved organic carbon (DOC 35 ), brine, as unfrozen liquid, is transported from the ice interior toward raction. We are therefore convinced that ikaite was always the precipitate. Thomas and Dieckmann ff 1995 ( polymorph for each sample collected, the visual characterisation by light mi- 3 Based on a thermomolecular pressure gradient as described by Normalized to a salinity of 35, (see A temporal change in ikaite concentration during the period of sampling between 14 The ikaite concentrations in land fast ice o Worster by X-ray di Higher brine salinities, andwater) correspondingly values, high resulted inlower a parts more likely in precipitation seaseawater of values. ice ikaite where However, near it temperatures theoccurs, is are surface and still than our higher not interpretation in and clear isrameters brine at confounded measured salinity what because during the point can sample variousprecipitation. in drop biogeochemical collection time to pa- ikaite do precipitation not reflect conditions at the time of calcium carbonate precipitation iscentration widespread is in heterogenous, Antarctic as seain is ice, sea the albeit case ice that for ( itsCaCO most con- other biogeochemical parameters croscopy confirmed that the morphology of all crystals was identical to those analyzed a linear trend, similar toDON, the DOC other concentrations measured (from chemical SIPEXcorrelated parameters. and Neither significantly DDU phosphate, with campaign) nor theice TA amount (DDU horizons from campaign) of where hydrous the calcium brines were carbonate collected present from. in the 4 Discussion Our results together with previous observations ( nitrogen (DON increased, non-linearly, over the study time.shows Although phosphate the (normalized to sameover trend time as and remained DON low.activity. Alkalinity Only fell NO from almost 2600 to approximately 2200 µmol l temporal from spatial heterogeneity.the Values distribution from of CaCO the spatial experiment showed that 200 m away from the initialthan sampling those site. from This the coreikaite younger had sea crystals higher ice. throughout mineral concentrations Ice thetration core core (38.77 D8 mg and l from even snowprofiles in covered were the ice similar (Fig. snow to 7) those itself. had of the The amount highest of concen- to ikaite 27 in November core 2007 D8 was not (Fig.are observed. 7). in Values of the the same temporal range and (0.06 spatial experiment to 3.93 mg l but generally higher than the packin ice the cores top (Fig. 4): layer. Most Athat were higher the between resolution 2 highest sampling and 5 concentrations (2(Fig. mg cm) l of 5). over the the mineral Ice first were 10 core to in D10 15 the (Fig. cm showed top 6) 2 was taken to at 4 cm a of location the of cores older fast ice 133 cm thick, representative for all crystals foundfrom in 0.01 this study to (Fig. 126in mg 2). l older Ikaite fast concentrations ranged distribution ice. of Data the from ikaite(Fig. 3). 14 crystals ice with Though coresmost highest the of concentrations of highest the in the value values thea SIPEX in depth in top campaign pack of the 20 layers ice show cm first of (with wasconcentrations clearly ten the ranged ice 9.5 the exception mg centimeters between of 0.02 ikaite did two l andand ice not cores, S6 0.3 mg exceed S3 showed l and it 2 mg S6) to in ikaite be l the rafted pack sea ice, ice. ikaite Calcium carbonate crystals were found inand all samples glacial analyzed, ice. including snow, Mineral seawas ice phase the identification precipitate of present. selected Sincesame samples all morphological crystals confirmed extracted features, that from it ikaite the is ice cores most showed likely the that the XRD identification as ikaite is 3 Results 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , , 3 ). 1993 Delille ) or up , ; Perovich formation 3 flux in open 2011 ). However, et al. 2011 , 2 in the sea ice , ff ) and favors the 3 ). Though there 2009 , 2009 crystals in the snow 1994 , 2009 . Based on the total , Bischo therein was not taken 3 Bowman and Deming 2 concentration even on , − 3 cult to draw conclusions 3 ffi ) then the precipitation of Rysgaard et al. ; 2008 ( ) which supports the hypothesis Obbard et al. ). The accumulated brine at the ). Based on our observations we ; 2009 precipitation ( ) we calculate that CaCO Rysgaard et al. erences in the amount of precipitated , 2012 2002 3 ff ) have shown that DOM influences the , 2009 Takahashi et al. , 2002 ( , ff , ◦ 2010 ). This also coincides with findings of ele- ff , 1978 ( 514 513 2008 , Comiso Perovich and Richter-Menge precipitation ( Aslam et al. 3 Comiso and Nishio . Besides the repression by polyphosphate and mag- ) postulate that hydrated salts may play an important Takahashi et al. concentrations were on the same order of magnitude 3 3 Rankin and Wol Berner et al. 1970 Rankin and Wol ( ; Nedashkovsky et al. ; ) and Kandianis et al. 1994 , 2002 1988 , ( ´ elie were expected to inhibit CaCO precipitation during frost flowers and sea ice formation as discussed above. 3 would be responsible for a flux between 0.04 and 3 TgC. For both the Arctic Dickens and Brown Tison et al. 3 , microbial biomass, such as cell surfaces and/or EPS, catalyze the precipitation ; ) and the top layer of sea ice ( Terre Ad Previous studies have pointed out the importance of sea ice for the carbon uptake It is not possible to determine the temporal development of CaCO The high concentrations of DOC and DON found in sea ice during the campaign Higher values of calcium carbonate in some middle layers of sea ice were attributable ikaite ff CaCO and Antarctic this wouldoceanic be water between at 0.1 % high and latitudes 4.5 % ( of the air-sea CO polar carbon flux. Considering polynyas with new sea ice forming during the winter and carbon flux in thetogether Southern with Ocean. the Assuming ice the cover same from distribution in Arctic sea ice to 13 % for theis Southern a Ocean large south amountinto of of account 50 ikaite for in theremains the calculation, elusive. snow, since the the However, amount distribution of of of widespread CaCO CaCO this would be a significant addition to the in sea ice potentially could represent a contribution of between 0.1 and 6 Tg C to the to the carbonice, cycle. since the For amount simplicity inin the we the lower take top part into was 10seasonal cm negligible. ice account cover of Absolute only in values sea the the of Antarctic ice ikaite top ( ranged found 10 cm between of 0.1 sea and 6.5 g m propose a first estimate of the possible contribution of calcium carbonate precipitation of CaCO in polar oceans due2006 to i.e. CaCO of calcium carbonate ( vated abundance of bacteria and2010 exopolymers in frost flowers ( anhydrous polymorphs of CaCO nesium ions on the precipitationforms, of anhydrous calcium carbonatepart in in favour of biological hydrated mineralization.Ω Taking this into account, additionally to the elevated investigated. This issmall due scales. to The reason the forin extreme this many variability heterogeneity sea might in ice be CaCO lastly due properties bacterial to activity. ranging the The from spatial inherent and temperature, variability small temporal salinity, scales heterogeneity texture, are as already chemistry shown apparenta by and on similar the range spatial in and theon temporal data the studies. temporal for Analyses, evolution both of however, campaigns. show the Thus, precipitation it of is ikaite. di o Zullig and Morse precipitation of calcium carbonate. However, these studies refer only to the inhibition for resulting one. Although CaCO in pack ice and land fastcalcium ice there carbonate. appear to The befast di highest sea values ice, were followed by recorded high in amounts approximately in land 1 yr fast ice old and land the lowest in pack ice. cium carbonate precipitation alsoobserved in takes older place land duringsnow fast cover subsequent can ice sea also (Fig. be iceillary 6). explained growth transport, by the The as which thermomolecular occurrence is pressureice of supported interface gradient as calcium and by described cap- the carbonate above maximum in (Fig. occurrence 7). the of ikaiteto at rafting the of snow floeswhere subsequent to the sea surface ice layer formation. of Floes one which of slide the over floes each other is transformed into a middle layer of the precipitation of salts. Underand those conditions Richter-Menge frost flowers mayconditions start not to necessarily grow leading ( precipitation to if frost the flower temperature is formation, low may and also salinity lead is to high. CaCO It appears that hydrous cal- surface has a salinity of about 100 ( the relatively colder surface ( 5 5 25 20 15 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , 3 3 ), 2008 ( Sander ´ erard, all Rysgaard erent types ff precipitation in 513 3 Sala et al. , which is released during doi:10.1029/2007JC004257 2 precipitation in di 3 514 ¨ 514 oller, Thomas Spangenberg, Michael flux. , in brine, and CaCO 2 ´ would be released to the atmosphere Emile Victor (IPEV) for the logistic assis- 506 2 514 506 2 , 2010. CO ). It would be essential to determine and p ) which describes the contribution of CaCO 516 515 2011 ( 2010 ( precipitation mainly occurs during young sea ice and 513 , in press, 2012. , 3 (all at Forschungszentrum Karslruhe) for technical and comput- 507 C: environmental and paleoclimatic implications for Thinolite Tufa, ff ◦ Loose et al. in sea ice. We showed the heterogenous occurrence of CaCO to 25 3 ◦ We thank the EPONTA (EPONTic micro-algae adapted to sea-ice) pro- doi:10.1029/2010GL043020 ) and pathways during sea ice formation to fully quantify the contribution of Sander and Morin 2 2011 O from 0 , ) and 2 H · 514 precipitation, is rejected to the underlying water column. While sea ice is still 3 , J. L., Fitzpatrick, J. A., and Rosenbauer, R. J.: The solubility and stabilization of ikaite 2007 2006 3 ff ( ( E, SSM/I, and2008. SMMR data, J. Geophys. Res, 113, C02S07, flowers and implications forLett., atmospheric 37, chemistry L13501, and microbial dispersal, Geophys. Res. cipitation from supersaturated seawater, Am. J. Sci., 278, 816–837, 1978. CaCO J. Geol., 101, 21–33, 1993. Ice: An Introduction to itsand Physics, Chemistry, Dieckmann, Biology G. and S., Geology, edited Blackwell, by: Oxford, 2010. Thomas, D. N. sea ice, J. Geophys. Res., 90, 9194–9198, 1985. doi:10.1007/s00300-011-1112-0 Dieckmann, G. S.,dynamics and and Thomas, bacterial D.: growth Dissolved during extracellular sea polymeric ice substance formation (dEPS) in an ice tank study, Polar Biol., With ikaite mainly in the top layer of sea ice our findings support the work of ¨ unsch, and Karlheinze Cer Comiso, J. C. and Nishio, F.: Trends in the sea ice cover using enhanced and compatible AMSR- Bowman, J. and Deming, J.: Elevated bacterial abundance and exopolymers in saline frost Bischo Berner, R., Westrich, J. T., Graber, R., Smitz, J., and Martens, C.: Inhibition of aragonite pre- Comiso, J. C.: Large-scale characteristics and variability of the global sea ice cover, in: Sea Anderson, L. G. and Jones, E. P.: Measurement of total alkalinity, calcium, and sulfate in natural and the Leverhulme Trust forNE 1564/2-1 funding. (SPP1158). We thank the DFG for financial support through grand References Aslam, S., Underwood, G. J. C., Kaartokallio, H., Norman, L., Autio, R., Fischer, M., Kuosa, H., ing support before and duringsamples the for measurements, mineralogy as and well syntheticthe as ikaite scientists, Christiane and and Uhlig photography. technicians for We fromwell preparing also the as the thank french the captain Frank research and G station crewtic Dumont of Division the d’Urville, polar for Antarctica vessel all as Astrolabe their and help the pilots and of support. the Australian David Antarc- Thomas and Louiza Norman thank NERC (UK) W gram for funding andtance Institut during Polaire Paul- Franc¸ais, the DDU campaign. We thank Harald Z quantify the CO calcium carbonate precipitation to the air-sea CO distribution of CaCO in sea iceoceans. and However, provide larger an scaleof quantification estimate sea of ice of CaCO in its bothparameters the significance Arctic measured and for Antarctic during is the sampleof necessary carbon to precipitation, collection validate much cycle these do work findings. in not isprecipitation Since polar within needed reflect sea to conditions ice evaluate and at the its conditions the fate ofAcknowledgements. during time calcium sea carbonate ice melt. to aeolian transport. 5 Conclusions This is the first study providing a systematic investigation of the spatial and temporal and would thus notet contribute al. to the sea ice carbon pump as proposed by et al. since ikaite crystals at the snow-ice interface and in the snow are more likely exposed frost flower formation, this phenomenon mightthe then air-sea contribute flux. even to However, this aCaCO larger would extent be to only the casepermeable if during CO sea icethe formation, top high layer of sea ice, a large amount of CO taking into account, that CaCO precipitation to ozone depletion events. It also supports the work of 5 5 20 25 15 10 10 25 15 20 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , , , - ∼ 4 510 507 , 506 513 514 514 , 507 510 509 , dimethyl- 506 from brines , 2 506 3 , 2002. ,O 507 2 , 2004. , 2011. 510 ` , 2008. ege, 2006. 508 ects of snow, snowmelting 507 ff ` ege, Li 507 fluxes in the open and coastal doi:10.1016/j.dsr2.2010.10.030 O) discovered in Arctic sea ice, , 2011. 2 2 , 2010. 6H degassing during sea ice formation, 506 · ´ e de Li 3 2 512 ¨ ottlicher, J., Steininger, R., Kennedy, H., doi:10.1029/2002JD002492 flux, J. Glaciol., 56, 262–270, 2010. doi:10.1029/2009JC006058 doi:10.1016/j.gca.2003.07.004 2 514 ¨ ottlicher, J., Gerland, S., Granskog, M. A., and 515 517 518 exchange, Mar. Chem., 49, 61–69, 2009. , produced by the precipitation of CaCO 2 doi:10.1029/2008GL033540 2 506 513 , E. W., and Atkinson, H. M.: Frost flower surface area ff doi:10.5194/tc-4-227-2010 , 2011. , 2009. doi:10.1016/j.dsr2.2010.10.033 513 O system, Geochim. Cosmochim. Ac., 65, 1883–1896, 2001. 2 , F.: Determination of nutrients, in: Methods of Seawater Analysis, , E. W.: Frost flowers: implications for tropospheric chemistry and ice ff , K., Ehrhardt, M., and Kremling, K., Wiley-VCH, Weinheim, 159–228, -H ff ff 2 506 -CO 3 514 -CO 3 precipitation in advection-dominated transport regimes, Geol. Soc. Am. B., 120, 442– 508 510 3 , Inorgan. Chem., 9, 480–486, 1970. ◦ 120 doi:10.5670/oceanog.2011.72 line UV digestion with510 the original Kjedahl method, Anal. Chim. Acta,and 276, 287–293, material 1993. transport across the frozen interface, Oceanography, 24(3), 202–218, mental evidence for carbonateGeochim. precipitation Cosmochim. Ac., and 68, CO 1749–1761, core interpretation, J. Geophys. Res., 107, 4683, CaCO 450, 2008. lutes and gases insystems, experimental Geochim. freezing Cosmochim. Ac., of 62, dilute 3637–3655, solutions: 1998. implications for natural glacial and chemistry as adoi:10.1029/2009JD012481 function of salinity and temperature, J. Geophys. Res., 114, D20305, bon removal andsummer, isotopic Mar. enrichment Ecol. Progr. in Ser., 386, Antarctic 15–27, sea 2009. ice99, gap 16341–16350, layers 1994. during early austral solved organic carbon analyzer, Anal. Chem., 68, 3090–3097, 1996. of dissolved organic matterAntarctic (DOM) sea and ice, chromophoric2011. dissolved Deep-Sea organic Res. matter Pt. (CDOM) in II, 58, 1075–1091, and refreezing processes on air–sea-ice CO Meiners, K. M., Lannuzel, D., van der Merwe, P., and Dieckmann, G. S.: The characteristics in sea ice, J. Geophys. Res., 86, 11041–11043, 1981. time series, J. Geophys. Res., 116, C02028, Thomas, D. N.:The Brief Cryosphere, Communication: 4, 227–230, Ikaite (CaCO Hampshire, 1937. edited by: Grassho 1983. OH-HCO ecobiogeochemistry of East Antarctic packRes. ice Pt. during II, the 58, winter-spring 1172–1181, transition, Deep-Sea Owens, O., Raudsepp, M., and Sutherland, N.: Carbon dynamics inarctic sea according ice: to a thetion surveys winter of performed flux the at role north of pole the drifting arctic station ice 34 in and the CO characteriza- Wolf-Gladrow, D., and Thomas, D.ice, N.: Geophys. Calcium Res. carbonate Lett., as512 ikaite 35, crystals L08 501, in Antarctic sea − 508 waters of the Southern Ocean, Ph. D. thesis, Universit sulfide) dynamics in spring Antarctic fast ice, Limnol. Oceanogr, 52, 1367–1379, 2007. Loose, B., Miller, L., Elliott, S., and Papakyriakou, T.: Sea ice biogeochemistry Kroon, H.: Determination of nitrogen in water: comparison of continuous flow method with on- Rankin, A. M. and Wol Papadimitriou, S., Kennedy, H., Kattner, G., Dieckmann, G. S., and Thomas, D. N.: Experi- Killawee, J. A., Fairchild, I. J., Tison, J.-L., Janssens, L., and Lorrain, R.: Segregation of so- Papadimitriou, S., Thomas, D., Kennedy, H., Kuosa, H., and Dieckmann, G. S.: Inorganic car- Obbard, R. W., Roscoe, H. K., Wol Qian, J. and Mopper, K.: An automated, high performance, high temperature combustion dis- Kandianis, M., Fouke, B., Johnson, J., and Inskeep, W.: Microbial biomass: a catalyst for Perovich, D. K. and Richter-Menge, J. A.: Surface characteristics of lead ice, J. Geophys. Res., Nomura, D., Yoshikawa-Inoue, H., Toyota, T., and Shirasawa, K.: E Norman, L., Thomas, D. N., Stedmon, C. A., Granskog, M. A., Papadimitriou, S., Krapp, R. H., Jones, E. P.and Coote, A. R.: Oceanic CO Hanson, H. and Korole Meiners, K., Norman, L., Granskog, M. A., Krell, A.,Miller, Heil, L., P., and Papakyriakou, Thomas, T., D. N.: Collins, Physico- E., Deming,Nedashkovsky, A., J., Khvedynich, S., Ehn, and Petrovsky, T.: J., Alkalinity of Macdonald, sea ice in R., the high-latitudinal Mucci, A., Gitterman, K. E.: Thermal analysis of seawater, CRRELTL287, USACRREL, Hanover, New Marion, G. M.: Carbonate mineral solubility at low temperatures in the Na-K-Mg-Ca-H-Cl-SO Dieckmann, G. S., Nehrke, G., Uhlig, C., G Dieckmann, G. S., Nehrke, G., Papadimitriou, S., G Dickens, B. and Brown, W. B.: The crystal structure of calcium carbonate hexahydrate at Delille, B., Jourdain, B., Borges, A. V., Tison, J.-L., and Delille, D.: Biogas CO Delille, B.: Inorganic carbon dynamics and air-ice-sea CO 5 5 30 25 25 20 30 15 20 10 15 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , 2 507 , 2008. ¨ ortzinger, A., Stein- 514 flux over the global oceans, , 2009. 2 515 515 , , 507 507 , 506 doi:10.1016/j.epsl.2008.03.045 , 2010. 514 , 515 519 520 , 2007. 514 , 507 , , and net sea–air CO , 2 507 512 507 CO 506 , p 506 doi:10.1016/j.dsr2.2008.12.009 , 2006. , 2009. 513 , 508 507 exchange in the Arctic and Southern Oceans, Tellus B, 63, 823–830, 2011. doi:10.5194/acp-10-7655-2010 2 doi:10.1029/2006JC003572 515 , 510 512 514 , m, T., Hoppema, M., Olafsson, J., Arnarson, T., Tilbrook, B., Johannessen, T., Olsen, A., ff 2009. Hales, B., Friederich,Metzl, G., N., Chavez, Yoshikawa-Inoue, F., H.,ho Sabine, Ishii, C., M.,Bellerby, Watson, Midorikawa, R., A., T., Wong, Nojiri, Bakker, C.,decadal Y., D., change Delille, K Schuster, in B., U., surfaceDeep-Sea Bates, ocean Res., N., 56, 554–577, and de Baar, H.:2010. Climatological mean and Thomas, D., and Bowie,tion A.: in East Biogeochemical Antarctic observations sea115, ice: during 163–175, evidence 2009. the of winter–spring iron and transi- exopolysaccharide controls, Mar. Chem., Phys. Rev. E, 51, 4679–4689, 1995. 1667–1678, 1988. doi:10.5194/acp-6-4653-2006 in seawater and related solutions: I. Fatty acid adsorption, Geochim. Cosmochim. Ac., 52, tial trigger for tropospheric ozone depletion events, Atmos. Chem. Phys., 6, 4653–4658, physico-chemical controls on gasJ. content Glaciol., and 48, composition 177–191, during 2002. growth of young sea ice, 515 “Precipitation of salts inMorin freezing et seawater and al., ozone published10, depletion in 7655–7658, events: Atmos. a Chem. status Phys., report”, 8, by 7317–7324, 2008, Atmos. Chem. Phys., Mortensen, J., Papadimitriou, S.,the air-sea Thomas, CO D. N.,506 and Tison, J. L.: Sea iceMarino, contribution F., to Ricci, P., andDome De and Giudici, Ross G.: Seaplications, Evidence area) Earth of East Planet. calcium Sci. Antarctica carbonates Lett., snow 271, in and 43–52, coastal firn: (Talos environmental and climatic im- doi:10.1029/2008JC005088 transport during sea ice112, growth and C03 016, decay: a carbon pump in polar seas,uptake J. due Geophys. to Res., sea ice growth and decay in the Nordic Seas, J. Geophys. Res., 114, C09011, Thomas, D. N. and Dieckmann, G. S.: Sea Ice, 2nd edn., Wiley-Blackwell Publishing, Oxford, Sarma, D.: Geostatistics with Applications in Earth Sciences,Takahashi, 2nd T., edn., Sutherland, Springer, Heidelberg, S., Wanninkhof, R., Sweeney, C., Feely, R., Chipman, D. W., Wettlaufer, J. S. and Worster, M. G.: Dynamics of premelted films: frost heave in a capillary, van der Merwe, Lannuzel, D., Mancuso Nichols, C., Meiners, K., Heil, P., Norman,Zullig, L., J. J. and Morse, J. W.: Interaction of organic acids with carbonate mineral surfaces Sander, R., Burrows, J., and Kaleschke, L.: Carbonate precipitation in brine – a poten- Tison, J. L., Haas, C., Gowing, M. M., Sleewaegen, S., and Bernard, A.: Tank study of Sander, R. and Morin, S.: Introducing the bromide/alkalinity ratio for a follow-up discussion on Sala, M., Delmonte, B., Frezzotti, M., Proposito, M., Scarchilli, C., Maggi, V., Artioli, G., M, D., Rysgaard, S., Bendtsen, J., Delille, B., Dieckmann, G. S., Glud, R. N., Kennedy, H., Rysgaard, S., Bendtsen, J., Pedersen, L. T., Ramløv, H., and Glud, R. N.: Increased CO Rysgaard, S., Glud, R. N., Sejr, M. K., Bendtsen, J., and Christensen, P. B.: Inorganic carbon 5 5 30 25 10 20 15 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 35 78 133 101 in cm melted sea ice, Ikaite TA 1 − 35 DOC 35 DON 35 ] 4 [SNH 35 ´ ] elie (DDU) in November 2007, S1 to S14 from − 3 522 521 [NO 35, values in µmol, ikaite in mg l + ] = 2 Terre Ad S ff [NO 1 yr), 2 cm sections 16 35 ] = 2 [NO 35 [Si] an old chunk catched by new ice pancakes at an earlier stage rafted ice chunks 35 ] − 2 4 Nutrient data normalized to Types and thickness of sea ice during SIPEX and DDU campaign. Sample [PO D-SH 1D-SH 2D-SH 0.50 3D-SH 1.53 4 50.30D-SH 0.30 5 41.39D-SH 1.33 6 0.12 62.18D-SH 1.77 7 0.14 53.12S1 0.45 0.05 68.80S2 0.47 0.07 16.17 49.83S3 0.11 10.63 55.53S4 0.08 1.75S5 3.06 0.03 0.92S6 3.11 36.37 0.37 1.17S7 4.71 52.21 2.04 N/A 0.14S8 0.98 40.07 0.64 4.91 0.36 0.45S9 0.20 17.50 1.57 0.25 N/A 0.91S10 45.91 85.99 N/A 146.17 1.47S11 8.45 28.48 45.52 1.93 1.03 0.18 0.32 0.68 N/A 33.41S12 32.07 N/A 78.80 0.25 N/A 0.77 27.75S13 2573.79 2236.36 2.78 180.04 28.15 52.25 12.51S14 0.07 183.44 0.22 1.23 55.56 0.13 N/A N/A 27.59 N/A 130.84 N/A 28.18 1.58 2370.92 2311.20 N/A 54.95 N/A 1.44 195.34 28.64 0.53 0.16 2171.08 N/A N/A 0.27 0.04 N/A 2.40 N/A 2394.29 42.63 29.93 2.35 N/A 2215.04 46.92 N/A 41.52 0.10 4.06 N/A 33.89 N/A N/A 68.24 0.13 0.34 N/A 3.15 49.46 1.59 9.69 N/A N/A 0.98 N/A N/A 23.78 N/A 55.68 N/A N/A N/A 10.00 67.31 3.55 5.89 N/A N/A N/A N/A N/A 1.47 3.89 61.38 N/A N/A N/A N/A N/A 4.90 N/A 0.49 N/A N/A 43.33 N/A 4.94 73.15 0.7 0.28 N/A N/A N/A 5.00 N/A 73.14 N/A 0.87 N/A 67.31 N/A N/A N/A 1.71 N/A N/A N/A N/A N/A S14D1D2D3 SIPEXD4 Pack ice DDUD5 DDUD6 Young (approx. 3 month) DDU fastD7 Young ice, (approx. 10 3 cm month) sections DDU fastD8 Young ice, (approx. 10 3 cm month) sections DDU fastD9 Young ice, (approx. 10 3 cm month) sections DDU fastD10 Young ice, (approx. 10 3 cm month) sections DDU fastD-SH1 Young ice, (approx. 10 3 cm month) sections DDU fastto Young ice, D-SH6 (approx. 10 3 cm month) sections DDU fastD-SP1 Young ice, (approx. DDU DDU 2 3 cm month) sections fastto Young ice, DSP25 (approx. 2 3 cm Fast Ice month) sections, ice from fast snow (age sackholes ice, on in 2 DDU top cm fast sections ice Top 10 cm of 65 fast ice 65 60 60 16 60 60 10 14 64 30 10 Sample CruiseS1 Sample typeS2S3S4 SIPEXS5 SIPEX Pack iceS6 SIPEX Pack iceS7 SIPEX Pack ice, raftedS8 sea ice SIPEX Pack iceS9 SIPEX Fast ice betweenS10 grounded icebergs Heavily SIPEX rafted ice floes SIPEX Pack ice SIPEX Large level floe SIPEX Heavily rafted and Large deformed level ice floe,coring site on an adjecent rafted area, probably Sample thickness 85 49 51 98 81 98 55 37 53 S11S12S13 SIPEX Rafted floe, ice SIPEX surface very rough SIPEX Rafted probably ice floes crushed together Rafted floes, ice surface very rough probably consisting of thin 109 Table 2. D-SH1 to D-SH7 fromsea land ice fast in ice East o Antarctic (see map) between September and October 2007. Table 1. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 524 523 ´ elie. Terre Ad ff Light microscopy image of ikaite crystals taken from a single bulk sea ice sample from Locations of ice stations sampled during SIPEX and DDU campaign. Fig. 2. land fast ice o Fig. 1. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ´ elie Terre Ad ff erent ice cores taken between ff 526 525 Distribution of ikaite in sea ice during SIPEX cruise in di Distribution of ikaite in sea ice during DDU campaign in land fast sea ice o sampled in November 2007. Fig. 4. September and October 2007 in East Antarctic. Fig. 3. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ´ elie Terre ff Terre Ad ff 3 month) land fast sea ice o ≈ 1 yr) land fast sea ice, o ≈ 528 527 Distribution of ikaite in the top layer of young ( Distribution of ikaite in the top layer of older ( ´ elie (DDU). Fig. 6. (DDU) in November 2007 core D10. Fig. 5. Ad Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ff ff bulk = amount of ikaite, red line = 20 m grid with sample points every 5 m by × 530 529 melted sea ice. 1 − ´ ´ elie (DDU) in November 2007, core D8, Black line elie (DDU) in November 2007 on a 20 m Contour plot of the spatial distribution of ikaite in the first 10 cm of land fast sea ice o Distribution of ikaite across the snow-ice interface from top layer of land fast sea ice o 5 m. Values are in mg ikaite l Terre Ad Fig. 8. salinity. Terre Ad Fig. 7.