Organic Carbon in Antarctic Snow: Spatial Trends and Possible Sources

Organic carbon records in Antarctic snow are sparse despite the fact that it is of great significance to global carbon dynamics, snow photochemistry, and air–snow exchange processes. Here, surface snow total organic carbon (TOC) along with sea-salt Na⁺, dust, and microbial load of two geographically distinct traverses in East Antarctica are presented, viz. Princess Elizabeth Land (PEL, coast to 180 km inland, Indian Ocean sector) and Dronning Maud Land (DML, ∼110–300 km inland, Atlantic Ocean sector). TOC ranged from 88 ± 4 to 928 ± 21 μg L^–1 in PEL and 13 ± 1 to 345 ± 6 μg L^–1 in DML. TOC exhibited considerable spatial variation with significantly higher values in the coastal samples (<i>p</i> < 0.001), but regional variation was insignificant within the two transects beyond 100 km (<i>p</i> > 0.1). Both distance from the sea and elevation influenced TOC concentrations. TOC also showed a strong positive correlation with sea-salt Na⁺ (<i>p</i> < 0.001). In addition to marine contribution, in situ microorganisms accounted for 365 and 320 ng carbon L^–1 in PEL and DML, respectively. Correlation with dust suggests that crustal contribution of organic carbon was marginal. Though TOC was predominantly influenced by marine sources associated with sea-spray aerosols, local microbial contributions were significant in distant locations having minimal sea-spray input

Origin and Sources of Dissolved Organic Matter in Snow on the East Antarctic Ice Sheet

Polar ice sheets hold a significant pool of the world’s carbon reserve and are an integral component of the global carbon cycle. Yet, organic carbon composition and cycling in these systems is least understood. Here, we use ultrahigh resolution mass spectrometry to elucidate, at an unprecedented level, molecular details of dissolved organic matter (DOM) in Antarctic snow. Tens of thousands of distinct molecular species are identified, providing clues to the nature and sources of organic carbon in Antarctica. We show that many of the identified supraglacial organic matter formulas are consistent with material from microbial sources, and terrestrial inputs of vascular plant-derived materials are likely more important sources of organic carbon to Antarctica than previously thought. Black carbon-like material apparently originating from biomass burning in South America is also present, while a smaller fraction originated from soil humics and appears to be photochemically or microbially modified. In addition to remote continental sources, we document signals of oceanic emissions of primary aerosols and secondary organic aerosol precursors. The new insights on the diversity of organic species in Antarctic snowpack reinforce the importance of studying organic carbon associated with the Earth’s polar regions in the face of changing climate

PAGES2k_v2.0.0-ts.pklz

Python-readable data structur

Quality-control dashboards for ocean records

Quality-control dashboards for ocean record

Quality-control dashboards, South America

Quality-control dashboards for South American record

Loading instructions

in GitHub Markdown format<div><br></div><div>Change note [5 April 2019]: Original instructions in LoadData.md are now obsolete, following updates to the LiPD utilities. The instructions now point to recently published Jupyter notebooks that illustrate how to use the PAGES 2k LiPD files to reproduce some figures from the paper, or carry out other analyses.<br></div

PAGES2k_v2.0.0_LiPD.zip

Original records in the Linked Paleo Data (http://wiki.linked.earth/Linked_Paleo_Data) forma

Quality-control dashboards, Arctic

Quality-control dashboards for Arctic record

HADCRUT4.2 temperature data

Matlab data file containing the GraphEM- infilled version of HadCRUT4.