@article {2921,
	title = {Climate control on terrestrial biospheric carbon turnover},
	journal = {Proceedings of the National Academy of Sciences},
	volume = {118},
	year = {2021},
	month = {Nov-02-2022},
	pages = {e2011585118},
	abstract = {Terrestrial vegetation and soils hold three times more carbon than the atmosphere. Much debate concerns how anthropogenic activity will perturb these surface reservoirs, potentially exacerbating ongoing changes to the climate system. Uncertainties specifically persist in extrapolating point-source observations to ecosystem-scale budgets and fluxes, which require consideration of vertical and lateral processes on multiple temporal and spatial scales. To explore controls on organic carbon (OC) turnover at the river basin scale, we present radiocarbon (C-14) ages on two groups of molecular tracers of plant-derived carbon-leaf-wax lipids and lignin phenols-from a globally distributed suite of rivers. We find significant negative relationships between the C-14 age of these biomarkers and mean annual temperature and precipitation. Moreover, riverine biospheric-carbon ages scale proportionally with basin-wide soil carbon turnover times and soil C-14 ages, implicating OC cycling within soils as a primary control on exported biomarker ages and revealing a broad distribution of soil OC reactivities. The ubiquitous occurrence of a long-lived soil OC pool suggests soil OC is globally vulnerable to perturbations by future temperature and precipitation increase. Scaling of riverine biospheric-carbon ages with soil OC turnover shows the former can constrain the sensitivity of carbon dynamics to environmental controls on broad spatial scales. Extracting this information from fluvially dominated sedimentary sequences may inform past variations in soil OC turnover in response to anthropogenic and/or climate perturbations. In turn, monitoring riverine OC composition may help detect future climate-change-induced perturbations of soil OC turnover and stocks.},
	keywords = {Carbon cycle, carbon turnover times, fluvial carbon, plant biomarkers, radiocarbon},
	issn = {0027-8424},
	doi = {10.1073/pnas.2011585118},
	url = {https://www.researchgate.net/publication/349357864_Climate_control_on_terrestrial_biospheric_carbon_turnover},
	author = {Eglinton, Timothy I. and Galy, Valier V. and Hemingway, Jordon D. and Feng, Xiaojuan and Bao, Hongyan and Blattmann, Thomas M. and Dickens, Angela F. and Gies, Hannah and Giosan, Liviu and Haghipour, Negar and Hou, Pengfei and Lupker, Maarten and McIntyre, Cameron P. and Montlu{\c c}on, Daniel B. and Peucker-Ehrenbrink, Bernhard and Ponton, Camilo and Schefu{\ss}, Enno and Schwab, Melissa S. and Voss, Britta M. and Wacker, Lukas and Wu, Ying and Zhao, Meixun}
}
@article {2661,
	title = {On the Origin of Aged Sedimentary Organic Matter Along a River-Shelf-Deep Ocean Transect},
	journal = {Journal of Geophysical Research: Biogeosciences},
	volume = {124},
	year = {2019},
	month = {Jun-08-2021},
	pages = {2582 - 2594},
	abstract = {To assess the influences of carbon sources and transport processes on the C-14 age of organic matter (OM) in continental margin sediments, we examined a suite of samples collected along a river-shelf-deep ocean transect in the East China Sea (ECS). Ramped pyrolysis-oxidiation was conducted on suspended particulate matter in the Yangtze River and on surface sediments from the ECS shelf and northern Okinawa Trough. C-14 ages were determined on OM decomposition products within different temperature windows. These measurements suggest that extensive amounts of pre-old (i.e., millennial age) organic carbon (OC) are subject to degradation within and beyond the Yangtze River Delta, and this process is accompanied by an exchange of terrestrial and marine OM. These results, combined with fatty acid concentration data, suggest that both the nature and extent of OM preservation/degradation as well as the modes of transport influence the C-14 ages of sedimentary OM. Additionally, we find that the age of (thermally) refractory OC increases during across-shelf transport and that the age offset between the lowest and highest temperature OC decomposition fractions also increases along the shelf-to-trough transect. Amplified interfraction spread or C-14 heterogeneity is the greatest in the Okinawa Trough. Aged sedimentary OM across the transect may be a consequence of several reasons including fossil OC input, selective degradation of younger OC, hydrodynamic sorting processes, and aging during lateral transport. Consequently, each of them should be considered in assessing the C-14 results of sedimentary OM and its implications for the carbon cycle and interpretation of sedimentary records.},
	keywords = {Carbon cycle, hydrodynamic processes, organic carbon, radiocarbon, sediments},
	issn = {2169-8953},
	doi = {10.1029/2019JG005107},
	url = { https://doi.org/10.1029/2019JG005107},
	author = {Bao, Rui and Zhao, Meixun and McNichol, Ann and Wu, Ying and Guo, Xinyu and Haghipour, Negar and Eglinton, Timothy I.}
}
@article {2626,
	title = {Spatiotemporal Variation of the Quality, Origin, and Age of Particulate Organic Matter Transported by the Yangtze River (Changjiang)},
	journal = {Journal of Geophysical Research: Biogeosciences},
	volume = {123},
	year = {2018},
	month = {Jan-09-2018},
	pages = {2908 - 2921},
	abstract = {Information on the age dynamics of particulate organic matter (POM) in large river systems is currently sparse and represents an important knowledge gap in our understanding of the global carbon cycle. Here we examine variations in organic geochemical characteristics of suspended sediments from the Changjiang (Yangtze River) system collected between 1997 and 2010. Higher particulate organic carbon content (POC\%) values were observed in the middle reach, especially after 2003, and are attributed to the increase of in situ (aquatic) primary production associated with decreased total suspended matter concentrations. Corresponding C-14 values from depth profiles taken in 2009 and 2010 indicate spatial and temporal variations in POC sources within the basin. Two isotopic mass balance approaches were explored to quantitatively apportion different sources of Changjiang POM. Results indicate that contributions of biomass and pre-aged soil organic matter are dominant, regardless of hydrological conditions, with soil-derived organic carbon comprising 17-56\% of POC based on a Monte Carlo three-end-member mixing model. In contrast, binary mixing model calculations suggest that up to 80\% of POC (2009 samples only) derived from biospheric sources. The emplacement of the Three Gorges Dam and resulting trapping of sediment from the upper reach of the watershed resulted in a modification of POM C-14 ages in the reservoir. With the resulting decline in sediment load and increase in the proportion of modern POC in the lower reach, these changes in POM flux and composition of the Changjiang have significant implications for downstream carbon cycle processes.},
	keywords = {Changjiang, organic carbon, radiocarbon, suspended particulate matter, Three Gorges Dam},
	issn = {2169-8953},
	doi = {10.1029/2017JG004285},
	url = {http://doi.wiley.com/10.1029/2017JG004285http://onlinelibrary.wiley.com/wol1/doi/10.1029/2017JG004285/fullpdfhttps://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1029\%2F2017JG004285},
	author = {Wu, Ying and Eglinton, Timothy I. and Zhang, Jing and Montlu{\c c}on, Daniel B.}
}
@article {2765,
	title = {Hydrologic controls on seasonal and inter-annual variability of Congo River particulate organic matter source and reservoir age},
	journal = {Chemical Geology},
	volume = {466},
	year = {2017},
	month = {Jan-09-2017},
	pages = {454 - 465},
	abstract = {We present dissolved organic carbon (DOC) concentrations, particulate organic matter (POM) composition (δ13C, δ15N, ∆14C, N/C), and particulate glycerol dialkyl glycerol tetraether (GDGT) distributions from a 34-month time-series near the mouth of the Congo River. An end-member mixing model using δ13C and N/C indicates that exported POM is consistently dominated by C3 rainforest soil sources, with increasing contribution from C3 vegetation and decreasing contribution from phytoplankton at high discharge. Large C4 inputs are never observed despite covering ≈ 13\% of the catchment. Low and variable ∆14C values during 2011 [annual mean = (- 148 {\textpm} 82) {\textperthousand}], when discharge from left-bank tributaries located in the southern hemisphere reached record lows, likely reflect a bias toward pre-aged POM derived from the Cuvette Congolaise swamp forest. In contrast, ∆14C values were stable near - 50{\textperthousand} between January and June 2013, when left-bank discharge was highest. We suggest that headwater POM is replaced and/or diluted by C3 vegetation and pre-aged soils during transit through the Cuvette Congolaise, whereas left-bank tributaries export significantly less pre-aged material. GDGT distributions provide further evidence for seasonal and inter-annual variability in soil provenance. The cyclization of branched tetraethers and the GDGT-0 to crenarchaeol ratio are positively correlated with discharge (r >= 0.70; p-value <= 4.3 {\texttimes} 10- 5) due to the incorporation of swamp-forest soils when discharge from right-bank tributaries located in the northern hemisphere is high. Both metrics reach record lows during 2013, supporting our interpretation of increased left-bank contribution at this time. We conclude that hydrologic variability is a major control of POM provenance in the Congo River Basin and that tropical wetlands can be a significant POM source despite their small geographic coverage.},
	keywords = {biomarkers, Congo River, GDGTs, Particulate organic matter, radiocarbon},
	issn = {00092541},
	doi = {10.1016/j.chemgeo.2017.06.034},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0009254117303935},
	author = {Hemingway, Jordon D. and Schefu{\ss}, Enno and Spencer, Robert G.M. and Dinga, Bienvenu Jean and Eglinton, Timothy I. and McIntyre, Cameron and Galy, Valier V.}
}
@article { ISI:000348452800012,
	title = {Preferential burial of permafrost-derived organic carbon in Siberian-Arctic shelf waters},
	journal = {JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS},
	volume = {119},
	number = {{12}},
	year = {2014},
	month = {DEC},
	pages = {8410-8421},
	type = {Article},
	abstract = {The rapidly changing East Siberian Arctic Shelf (ESAS) receives large amounts of terrestrial organic carbon (OC) from coastal erosion and Russian-Arctic rivers. Climate warming increases thawing of coastal Ice Complex Deposits (ICD) and can change both the amount of released OC, as well as its propensity to be converted to greenhouse gases (fueling further global warming) or to be buried in coastal sediments. This study aimed to unravel the susceptibility to degradation, and transport and dispersal patterns of OC delivered to the ESAS. Bulk and molecular radiocarbon analyses on surface particulate matter (PM), sinking PM and underlying surface sediments illustrate the active release of old OC from coastal permafrost. Molecular tracers for recalcitrant soil OC showed ages of 3.4-13 C-14-ky in surface PM and 5.5-18 C-14-ky in surface sediments. The age difference of these markers between surface PM and surface sediments is larger (i) in regions with low OC accumulation rates, suggesting a weaker exchange between water column and sediments, and (ii) with increasing distance from the Lena River, suggesting preferential settling of fluvially derived old OC nearshore. A dual-carbon end-member mixing model showed that (i) contemporary terrestrial OC is dispersed mainly by horizontal transport while being subject to active degradation, (ii) marine OC is most affected by vertical transport and also actively degraded in the water column, and (iii) OC from ICD settles rapidly and dominates surface sediments. Preferential burial of ICD-OC released into ESAS coastal waters might therefore lower the suggested carbon cycle climate feedback from thawing ICD permafrost.},
	keywords = {biomarkers, carbon, permafrost, radiocarbon},
	issn = {2169-9275},
	doi = {10.1002/2014JC010261},
	author = {Vonk, Jorien E. and Semiletov, Igor P. and Dudarev, Oleg V. and Eglinton, Timothy I. and Andersson, August and Shakhova, Natalia and Charkin, Alexander and Heim, Birgit and Gustafsson, {\"O}rjan}
}
