Chlorofluorocarbons and noble gas measured on water bottle samples during POLARSTERN cruise ANT-XXIII/7

DOI

During the expedition a total of 550 samples on 37 CTD stations were collected for chlorofluorocarbons (CFC-11 and CFC-12). The water samples from the rosette system were collected into 100 ml glass ampoules and sealed off after a CFC free headspace of pure nitrogen had been applied. Furthermore, 310 samples from 30 stations were collected for helium isotopes (3He, 4He) and neon (Ne). The water samples from the niskin bottles were stored in clamped off copper tubes.The water samples for helium isotopes and neon from the CTD-bottle-system are tapped in copper tubes, preventing air contamination and bubbles during the filling of the tubes and squeezed at both ends to keep them gas tight during transportation and storage.In the IUP Bremen noble gas lab the samples are processed in a first step with a UHV (ultra high vacuum) gas extraction system. The required vacuum conditions are achieved by a rotary pump and an oil diffusion pump. To maintain contamination-free samples, the extraction system is checked for leaks on each sample separately. Sample gases are transferred via water vapour into a glass ampoule kept at liquid nitrogen temperature. Quality checks of this sample preparation line are done on a routine basis. This includes special vacuum checks and preparing accurately defined samples for internal control measurement.For analysis of the noble gas isotopes the glass ampoules are connected to a fully automated UHV mass spectrometric system equipped with a two stage cryo system. Every 2 to 4 samples the system is calibrated with atmospheric air standards (reproducibility <0.2%). Also measurement of line blanks and linearity are done. The performance of the Bremen facility is described in Sultenfus et al. (2009, doi:10.1080/10256010902871929).Error estimate for absolute noble gases concentrations:- D(4He) < 0.8 %- D(Ne) < 0.8 %- D(d3He) < 0.4 %The Chlorofluorocarbon (CFC-11 and CFC-12) water samples from the CTD-bottle-system are stored in glass ampoules without contact to the atmosphere during the tapping. Immediately after sampling the ampoules are flame sealed after a CFC free headspace of pure nitrogen had been applied.The loss of CFCs into the headspace is considered by a careful equilibration between liquid and gas phase under controlled conditions before the sealed ampoules are opened and a precise measurement of the volume of the headspace. The determination of CFC concentrations in the IUP Bremen gas chromatography lab is accomplished by purge and trap sample pre-treatment followed by gas chromatographic (GC) separation on a capillary column and electron capture detection (ECD). The system is calibrated by analyzing several different volumes of a known standard gas. CFC concentrations are calibrated on SIO98 scale (Prinn et al., 2000, doi:10.1029/2000JD900141). A more detailed description of the measurement system is given by Bulsiewicz et at. (1998, doi:10.1029/98JC00140).Accuracy (i.e. uncertainties of calibrated sample volume, calibration curve, extraction efficiency, standard and working gas; water blank):- CFC-12 < 1.7 %- CFC-11 < 2.9 %Precision (i.e. mean error from 22 replicate samples):- CFC-12 < 0.005 pmol/kg or < 0.8 % (which ever is greater)We do not give a value for the precision of CFC-12. Offline sample chromatograms regularly show a negative peak in the vicinity of the CFC-11 peak, which decreases the accuracy of CFC-11 in comparison to CFC-12, and which does not allow giving an objective estimate of a precision for CFC-11.Noble gas and CFC data were used in Hellmer et al., 2011, doi:10.5194/os-7-305-2011.Sampling on board and measurement of CFCs and noble gases at the IUP Bremen was funded by the Deutsche Forschungsgemeinschaft within the SPP 1158 "Antarktisforschung", grant RH 25/27. We thank Peter Lemke, Hartmut H. Hellmer and the scientific party to participate in the ANT-XXIII/7 expedition and for the excellent assistance and cooperation on board. We also thank the master and crew of RV Polarstern.Noble gas measurements: Jürgen Sültenfuß; CFC measurements: Klaus BulsiewiczQuality flags: ? = doubtful; / = bad; # = mean of replicates

Identifier
DOI https://doi.pangaea.de/10.1594/PANGAEA.770689
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.770689
Provenance
Creator Huhn, Oliver ORCID logo; Rhein, Monika ORCID logo; Sültenfuß, Jürgen ORCID logo; Bulsiewicz, Klaus
Publisher PANGAEA
Contributor Institut für Umweltphysik, Universität Bremen
Publication Year 2025
Rights Data access is restricted (moratorium, sensitive data, license constraints)
OpenAccess false
Representation
Resource Type Dataset
Format text/tab-separated-values
Size 2366 data points
Discipline Earth System Research
Spatial Coverage (-57.399W, -65.109S, -8.480E, -46.218N); South Atlantic Ocean; Scotia Sea, southwest Atlantic; Weddell Sea; Atlantic Ocean
Temporal Coverage Begin 2006-09-01T08:40:00Z
Temporal Coverage End 2006-10-19T19:39:00Z