Analysis of atmospheric and cryospheric signatures preserved as dissolved organic matter in ancient and modern ice cores using ultahigh resolution FTICR mass spectrometry

Historically, it has been an analytical challenge to detect and identify the organic components present in ice cores, due to the low abundance of organic carbon. Here, we used ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry, coupled with electrospray ionization, in order to detect and characterize the small amounts of organic matter in ice cores. We successfully identified molecular formulas and bulk structural properties of organic matter in both modern and ancient ice core and glacial samples from Wyoming, Greenland, and Antarctica. In addition, we were able to determine sources of DOM in our ice cores through data comparisons to recently reported studies of DOM derived from atmospheric aerosols (Mazzoleni et al., 2012), microbial and photochemical processing (Antony et al., in prep a), and oxidation chemistry (Waggoner et al., 2015). These source classifications allowed us to identify atmospheric signatures related to anthropogenic emissions of SOx compounds in post-industrial Greenland ice core samples. We also detected atmospheric signatures in Fremont and WAIS Divide samples related to the volcanic emissions of black carbon-like material resulting from the 1883 eruption of Mt. Krakatoa. Ancient Vostok ice cores reveal potential long-term oxidation chemistry occurring in the ice, as well as influences from climatic signatures related to biomass burning events. Our experimental results provide the first investigation of the sources and transformations of DOM preserved in ice, as they relate to the Industrial Revolution, volcanism, and global climate.