A data collation for climate-cooling gas dimethylsulphide in Antarctic snow, sea ice and underlying seawater

Brief description

The database is comprised of folders of measurements of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) in ice, snow, slush, water and brine. Data were collated and localised from a variety of studies from 1995-2018. Data come from peer-reviewed publications, field-reports, data repositories and direct contributions by field-research teams. This data compilation was carried out under the auspices of the Scientific Committee on Antarctic Research - ASPeCt program and the Scientific Committee on Ocean Research (SCOR) working group on Biogeochemical Exchange Processes at the Sea-Ice Interfaces (WG-140).

Each excel file represents one ice core, snow sample or water sample as a vertical profile with section depth ranges. The information of interest includes the upper limits and mean concentrations of DMS, particulate DMSP (DMSPp), dissolved DMSP (DMSPd) and total DMSP (DMSPt: DMSPd + DMSPp) measured in nanomoles per litre (nmol l-1), for the associated depths. Ancillary data such as nutrients, temperature and chlorophyl a concentrations are also included where possible, as well as descriptive data for the sampling sites, such as date, coordinates, type of ice, snow and ice thickness, core diameter, etc. Some of these studies are time series and some contain replicate cores at each station. To differentiate samples taken on the same date, voyage or location, the files are named accordingly:

Date_CRUISE_sampletype_sampleID_variable.xlsx

Example: 19971017_ASAC2100_ice_002_DMSP.xlsx

Notes:
• Files with unknown exact dates are named like so: *_19971000_*
• Not all filenames contain sample IDs. Sample IDs will be in the form of a three-digit number, or in the case of files from *ISPOL_snow*, ‘Sxx’ or ‘Ixx’, which correspond to snow samples over slush or over solid ice respectively. Sample ID for *_JCR92-* files are the words ‘Gertie’, ‘Herbie’ or ‘Isolde’ which correspond to station names from Turner et al. (1995).
• Files named with *_JARE48_ice_* have an extra column for combined measurements of DMS and DMSP, which begins in cell BG22.
• Data in this database was either made available by authors or extracted directly from figures using GRABIT.
• Data from files named with *_XVI_ice_* (Gambaro et al. 2004) were extracted using GRABIT, under the assumption that the figure 2 depth profiles related to ice cores and not under-ice water.

Lineage

Progress Code: onGoing

Statement: Where it was not possible to access raw data from a study, the Matlab package GRABIT was used to extract data directly from a figure. This software is only fit for a best approximation of the data in the figure, and often these values lacked ancillary data. The majority of data collated here are from spring/summer voyages and are focused around East Antarctica and the Antarctic Peninsula.

Notes

Purpose
Only a handful of studies have explored the concentrations of DMS and DMSP in Antarctic sea ice and what DMS/DMSP data have been recorded in Antarctic sea ice environments have not been collated or localised, and are often not publicly available. This database collated as much data as possible from these studies into one database to advance our understanding of the current spatial and temporal distribution of the data as well as inform future efforts. Collation was done following the following the protocols of the ASPeCt sea ice physics (http://aspect.antarctica.gov.au/) and BEPSII (https://sites.google.com/site/bepsiiwg140/home) programs. This database should provide useful, localised data for researchers who want to analyse and add to the current understanding of DMS in Antarctica. The database can be analysed using Martin Vancoppenolle’s Matlab package, the BEPSII ice core analyzer (Martin Vancoppenolle n.d.). We have written a complimentary script, ‘DMS Analyzer’, to accompany the package. This script allows the user to easily extract data from the database and make depth profiles that incorporate snow, ice and water layers.