Organic Carbon in Antarctic Snow: Spatial Trends and Possible Sources

Abstract

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 (p < 0.001), but regional variation was insignificant within the two transects beyond 100 km (p > 0.1). Both distance from the sea and elevation influenced TOC concentrations. TOC also showed a strong positive correlation with sea-salt Na(+) (p < 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.

Distributions and light absorption property of water soluble organic carbon in a typical temperate glacier, southeastern Tibetan Plateau

“…It is known that organic compounds deposited on glaciers will experience a series of depletion processes and photochemical reactions (Grannas et al, 2004;Antony et al, 2011;Niu et al, 2017b). Depletion process of WSOC in surface aged snow was investigated based on successive insitu observations, the results indicated that WSOC concentrations were dramatically decreased with the time extension during the entire monsoon season (Fig.…”

“…Glacier ecosystem accumulates OC from in-situ primary production as well as from the deposition of impurities derived from anthropogenic and natural sources (Singer et al, 2012;Stibal et al, 2012). OC records in glaciers are of great significance to global carbon dynamics, snow photochemistry, and air-snow exchange processes (Antony et al, 2011;Niu et al, 2017a). It was also known that photochemical reactions of OC in snow and ice can release reactive gaseous species into the overlying atmosphere (Guimbaud et al, 2002;Grannas et al, 2004;Niu et al, 2017b).…”

“…Hydrophilic WSOC and OC are released from glaciers through glacial meltwater that discharges at the glacier terminus into proglacial aquatic ecosystems and streams. Various WSOC and IPC present in snow cover and glaciers, and the physical and photochemical processes occurring within them, can have a great effect on atmospheric and glacier chemistry (Jones et al, 2001;Domine and Shepson, 2002;Grannas et al, 2007;Antony et al, 2011). Moreover, glacier ice represents a significant hydrological reservoir of OC that merits deep consideration in studies of evaluating and addressing riverine carbon cycles and dynamics (Schuur et al, 2008;Hood et al, 2015).…”

“…Studies on concentrations, sources, light absorption properties, and historical variations of WSOC have been conducted at glaciers in the Qilian mountain (Yan et al, 2016(Yan et al, , 2015, Arctic (Hood et al, 2009;Stubbins and Dittmar, 2012), European ice core (Singer et al, 2012;May et al, 2013;Legrand et al, 2013b), and Antarctic (Lyons et al, 2007;Antony et al, 2011;Legrand et al, 2013a). However, the relevant dataset on WSOC is sparse in the TP (Spencer et al, 2014;Yan et al, 2015;Li et al, 2016a, b;Niu et al, 2017b) because of the harsh environmental and logistical difficulties.…”

Measuring Organic Carbon and Black Carbon in Rainwater: Evaluation of Methods

“…Reported DOC concentration in rainwater varies over five orders of magnitude, from 60 to 204,000 μg-C/L. The concentration of DOC in ice and snow is typically lower than in rainwater; for instance, the measured concentration in Antarctic snow ranged from 88 to 928 μg-C/L (Antony et al 2011) and in ice cores ranged from 2 to 100 μg-C/L (Preunkert et al 2011).…”