@article {2841,
	title = {Fossil Fuel Combustion Emission From South Asia Influences Precipitation Dissolved Organic Carbon Reaching the Remote Tibetan Plateau: Isotopic and Molecular Evidence},
	journal = {Journal of Geophysical Research: Atmospheres},
	volume = {123},
	year = {2018},
	month = {Apr-06-2019},
	pages = {6248 - 6258},
	abstract = {The dissolved organic carbon in precipitation (water-soluble organic carbon, WSOC) can provide a carbon subsidy to receiving ecosystems. The concentrations, isotopic signatures (δ13C/Δ14C), and molecular signatures (transform ion cyclotron mass spectrometry) of WSOC being delivered to Nam Co{\textemdash}a remote site on the inland Tibetan Plateau (TP){\textemdash}were compared to those of WSOC in the snowpack, and in wet deposition from urban cities fringing the TP. The average WSOC concentration at Nam Co (1.0 {\textpm} 0.9 mg C L-1) was lower than for the large cities (1.6 to 2.3 mg C L-1) but higher than in the snowpack samples (0.26 {\textpm} 0.09 mg C L-1). Based upon radiocarbon data, it is estimated that 15 {\textpm} 6\% of Nam Co WSOC was fossil derived, increasing to 20 {\textpm} 8\% for snowpack WSOC, 29 {\textpm} 4\% for Lhasa WSOC, and 34 {\textpm} 8\% for the three cities. Transform ion cyclotron mass spectrometry results revealed that the abundance of dissolved black carbon and sulfur-containing molecules of WSOC increased in the order Nam Co < snow pack < urban. The enrichment in 14C and depletion in dissolved black carbon and sulfurous organic molecules of Nam Co WSOC was suggestive of low, but still detectable inputs of fossil-derived organics to WSOC on the remote TP. Backward air mass trajectories for the precipitation events at Nam Co suggested that the fossil fuel contributions to WSOC in Nam Co region originated mainly from South Asia. This study provides novel radiocarbon age, chemistry, and source evidence that anthropogenic WSOC is delivered to the remote TP, one of the most remote regions on Earth.},
	doi = {10.1029/2017JD028181},
	url = {http://doi.wiley.com/10.1029/2017JD028181},
	author = {Li, Chaoliu and Chen, Pengfei and Kang, Shichang and Yan, Fangping and Tripathee, Lekhendra and Wu, Guangjian and Qu, Bin and Sillanp{\"a}{\"a}, Mika and Yang, Di and Dittmar, Thorsten and Stubbins, Aron and Raymond, Peter A.}
}
@article {2615,
	title = {Microbial decomposition of marine dissolved organic matter in cool oceanic crust},
	journal = {Nature Geoscience},
	volume = {11},
	year = {2018},
	month = {Jan-05-2018},
	pages = {334 - 339},
	abstract = {Marine dissolved organic carbon (DOC) is one of the largest active reservoirs of reduced carbon on Earth. In the deep ocean, DOC has been described as biologically recalcitrant and has a radiocarbon age of 4,000 to 6,000 years, which far exceeds the timescale of ocean overturning. However, abiotic removal mechanisms cannot account for the full magnitude of deep-ocean DOC loss. Deep-ocean water circulates at low temperatures through volcanic crust on ridge flanks, but little is known about the associated biogeochemical processes and carbon cycling.
Here we present analyses of DOC in fluids from two borehole observatories installed in crustal rocks west of the Mid-Atlantic Ridge, and show that deep-ocean DOC is removed from these cool circulating fluids. The removal mechanism is isotopically selective and causes a shift in specific features of molecular composition, consistent with microbe-mediated oxidation. We suggest organic molecules with an average radiocarbon age of 3,200 years are bioavailable to crustal microbes, and that this removal mechanism may account for at least 5\% of the global loss of DOC in the deep ocean. Cool crustal circulation probably contributes to maintaining the deep ocean as a reservoir of {\textquoteright}aged{\textquoteright} and refractory DOC by discharging the surviving organic carbon constituents that are molecularly degraded and depleted in C-14 and C-13 into the deep ocean.},
	keywords = {carbon, community, deep-ocean, DISTINCT, extraction, fluid-flow, HEAT, MID-ATLANTIC RIDGE, SEAWATER, WESTERN FLANK},
	issn = {1752-0894},
	doi = {10.1038/s41561-018-0109-5},
	url = {http://www.nature.com/articles/s41561-018-0109-5http://www.nature.com/articles/s41561-018-0109-5.pdfhttp://www.nature.com/articles/s41561-018-0109-5http://www.nature.com/articles/s41561-018-0109-5.pdf},
	author = {Shah Walter, Sunita R. and Jaekel, Ulrike and Osterholz, Helena and Fisher, Andrew T. and Huber, Julie A. and Pearson, Ann and Dittmar, Thorsten and Girguis, Peter R.}
}
@article {2459,
	title = {Source and biolability of ancient dissolved organic matter in glacier and lake ecosystems on the Tibetan Plateau},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {142},
	year = {2014},
	month = {Jan-10-2014},
	pages = {64 - 74},
	abstract = {The Tibetan Plateau is the world{\textquoteright}s largest and highest plateau and holds the largest mass of ice on Earth outside the ice-sheets of Greenland and Antarctica, as well as abundant lakes. This study examined the molecular and isotopic signatures of dissolved organic matter (DOM) along with its biolability in glacier ice, glacier-fed streams, and alpine lakes on the Tibetan Plateau. The aim was to assess the sources of DOM and the potential of DOM to provide a carbon subsidy to downstream ecosystems. Tibetan glaciers and glacier streams exhibited low dissolved organic carbon (DOC) concentrations (17.7{\textendash}27.9 μM) and ancient DOC radiocarbon ages (749{\textendash}2350 ybp). The optical properties, stable carbon isotope ratios (δ13C-DOC) and the molecular composition (Fourier transform ion cyclotron resonance mass spectrometry) of Tibetan glacier DOM are consistent with data from other glacier systems around the world. The geochemical signatures and the ancient apparent ages of Tibetan glacier DOM suggest a significant fraction is derived from the atmospheric deposition of pre-aged, possibly fossil fuel derived organics. Within the Tibetan alpine lakes, DOC was also ancient (525{\textendash}675 ybp), due to either inputs of pre-aged organics from glacier runoff, direct deposition, or due to the aging of organics in situ (i.e. a radiocarbon reservoir effect). The glacier ice and glacier stream sites exhibited high biolability of DOC and so provide a carbon subsidy to downstream environments that will change as glaciers on the Tibetan Plateau recede.},
	issn = {00167037},
	doi = {10.1016/j.gca.2014.08.006},
	url = {http://linkinghub.elsevier.com/retrieve/pii/S0016703714005018http://api.elsevier.com/content/article/PII:S0016703714005018?httpAccept=text/xmlhttp://api.elsevier.com/content/article/PII:S0016703714005018?httpAccept=text/plain},
	author = {Spencer, Robert G.M. and Guo, Weidong and Raymond, Peter A. and Dittmar, Thorsten and Hood, Eran and Fellman, Jason and Stubbins, Aron}
}
