@article {236,
	title = {Selective preservation of old organic carbon fluvially released from sub-Arctic soils},
	journal = {Geophysical Research Letters},
	volume = {37},
	year = {2010},
	note = {id: 886; 610KU Times Cited:7 Cited References Count:30Y},
	abstract = {Amplified climate warming in the Arctic may cause thaw-remobilization of its large soil organic carbon (SOC) pool. Here we assess the remobilization and preservation of old SOC by the watershed-integrated radiocarbon signature of molecular SOC markers released from northernmost Scandinavia. The radiocarbon analyses revealed a remarkable fractionation for identical vascular plant markers (similar to 420 parts per thousand or similar to 6000 (14)C years) upon settling from surface water to the underlying sediments. From this, we infer fluvial export of two SOC pools; a young surface peat component, and an old deep mineral soil component. The young pool exists as an easily degradable humic suspension, while the old pool is matrix protected from degradation and ballasted for preferential settling. The two soil types with highest OC in Arctic permafrost evidently exhibit different susceptibilities to degradation. Hence, a significant part of the thaw-released OC may simply be fluvially relocated to sediments instead of being emitted to the atmosphere. Citation: Vonk, J.E., B.E. van Dongen, and. Gustafsson (2010), Selective preservation of old organic carbon fluvially released from sub-Arctic soils, Geophys. Res. Lett., 37, L11605, doi:10.1029/2010GL042909.},
	issn = {0094-8276},
	doi = {10.1029/2010gl042909},
	author = {Vonk, J. E. and van Dongen, B. E. and Gustafsson, O.}
}
@article {271,
	title = {Contrasting lipid biomarker composition of terrestrial organic matter exported from across the Eurasian Arctic by the five great Russian Arctic rivers},
	journal = {Global Biogeochemical Cycles},
	volume = {22},
	year = {2008},
	note = {id: 819; 261FT Times Cited:10 Cited References Count:112Y},
	abstract = {Surface sediments outside the great Russian Arctic rivers (GRARs; Ob, Yenisey, Lena, Indigirka, and Kolyma) were investigated for their lipid biomarker composition to elucidate compositional distinctions of the exported organic matter (OM) across this continent-scale climosequence of the Siberian Arctic. The lipid biomarker composition is dominantly terrestrial (high molecular weight (HMW) n-alkanols, n-alkanoic acids, n-alkanes; branched glycerol dialkyl glycerol tetraethers (GDGTs), beta-sitosterol, other sterols, and triterpenoids) with only minor marine contributions (e. g., the ratio of terrigenous-to-aquatic n-alkanes was 17-80, the TOC/TN ratio was 10-16, and the branched and isoprenoid tetraether (BIT) index > 0.88). There is a large contribution of C-23 and C-25 homologues relative to other long-chained n-alkanes, suggesting substantial contribution of probably Sphagnum-derived OM. The C-23 and C-25 contribution decreases eastward, signaling either a decrease in the potential contribution of Sphagnum or a shift within the n-alkane distribution of Sphagnum species or increased aeolian input, due to more arid conditions in the east. Other distinctions in molecular OM composition across the climosequence include increased concentrations of both HMW n-alkanoic acids and beta-sitosterol relative to HMW n-alkanes in the eastern sediments. This suggests that the OM exported by the eastern GRARs is, despite their higher bulk radiocarbon ages, less degraded, which is consistent with increasing permafrost and a shorter annual thaw period in eastern Siberia. Taken together, this benchmark study of the current composition of terrestrially exported OM suggests distinguishing continent-scale trends in molecular composition of the OM across the west-east set of GRARs, which reflects both differences in vegetation and climate. If the climate in the eastern Russian Arctic region becomes more like the current state in the western part, these results would predict a greater degree of decomposition of the old terrestrial OM released by the eastern GRARs and thus greater remineralization and release as CO2 and methane.},
	issn = {0886-6236},
	doi = {10.1029/2007gb002974},
	author = {van Dongen, B. E. and Semiletov, I. and Weijers, J. W. H. and Gustafsson, O. R.}
}
