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

Abstract

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.

Fossil Fuel Combustion Emission From South Asia Influences Precipitation Dissolved Organic Carbon Reaching the Remote Tibetan Plateau: Isotopic and Molecular Evidence

“…Average concentrations of Nam Co WSOC were lower than urban WSOC concentrations but higher than snowpack WSOC concentrations (Table 1 and Figure S2a). The low concentrations of snowpack WSOC on the TP are in agreement with previous studies in Alaska , Antarctica (Antony et al, 2014;Barker et al, 2013), the European Alps , and Greenland (Grannas et al, 2004;Twickler et al, 1986). Given the photolability (Grannas et al, 2004) Note.…”

Snow‐borne nanosized particles: Abundance, distribution, composition, and significance in ice nucleation processes

“…We suggest specific amino acids, molecular weights of which match the above mentioned mass decreases, so the potential polymers are likely peptides and are shown in Figure a. Moreover, proteins and macromolecules have previously been observed in atmospheric aerosols [ Gelencsér , ; Jaenicke , ], as well as ice and snow [ Antony et al , ]. Even extracellular polymeric substances have been found in diamond dust from the Arctic [ Domine et al , ].…”

Influence of Biogenic Organics on the Chemical Composition of Arctic Aerosols

“…An ultrahigh‐resolution Fourier transform ion cyclotron resonance mass spectrometer (FT‐ICR MS) has been successfully used to resolve exceptionally complicated organic samples, such as crude oils and various organic matter derived from soil or water, by acquiring ultrahigh‐accuracy mass profiles of the samples, resulting in fast and accurate interpretations of the elemental compositions of complicated samples (Antony et al, ; Lobodin et al, ; Cho et al, ; Guigue et al, ; Ksionzek et al, ; Mazur et al, ; Jang, Choi, et al, ). Due to the versatile applicability of various ionization methods (i.e., electrospray ionization [ESI], atmospheric pressure chemical ionization, atmospheric pressure photoionization, and laser desorption ionization), an FT‐ICR MS can detect a wide range of target molecules, ranging from polar species to nonpolar species (Choi et al, ; Rathsack et al, ; Vahur et al, ).…”