@article {2628,
	title = {Temporal deconvolution of vascular plant-derived fatty acids exported from terrestrial watersheds},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {244},
	year = {2019},
	month = {Jan-01-2019},
	pages = {502 - 521},
	abstract = {Relatively little is known about the amount of time that lapses between the photosynthetic fixation of carbon by vascular land plants and its incorporation into the marine sedimentary record, yet the dynamics of terrestrial carbon sequestration have important implications for the carbon cycle. Vascular plant carbon may encounter multiple potential intermediate storage pools and transport trajectories, and the age of vascular plant carbon accumulating in marine sediments will reflect these different pre-depositional histories. Here, we examine down-core C-14 profiles of higher plant leaf wax-derived fatty acids isolated from high fidelity sedimentary sequences spanning the so-called "bomb-spike", and encompassing a ca. 60-degree latitudinal gradient from tropical (Cariaco Basin), temperate (Saanich Inlet), and polar (Mackenzie Delta) watersheds to constrain integrated vascular plant carbon storage/transport times ("residence times").

Using a modeling framework, we find that, in addition to a "young" (conditionally defined as < 50 y) carbon pool, an old pool of compounds comprises 49 to 78 \% of the fractional contribution of organic carbon (OC) and exhibits variable ages reflective of the environmental setting. For the Mackenzie Delta sediments, we find a mean age of the old pool of 28 ky (+/- 9.4, standard deviation), indicating extensive pre-aging in permafrost soils, whereas the old pools in Saanich Inlet and Cariaco Basin sediments are younger, 7.9 (+/- 5.0) and 2.4 (+/- 0.50) to 3.2 (+/- 0.54) ky, respectively, indicating less protracted storage in terrestrial reservoirs. The "young" pool showed clear annual contributions for Saanich Inlet and Mackenzie Delta sediments (comprising 24\% and 16\% of this pool, respectively), likely reflecting episodic transport of OC from steep hillside slopes surrounding Saanich Inlet and annual spring flood deposition in the Mackenzie Delta, respectively. Contributions of 5-10 year old OC to the Cariaco Basin show a short delay of OC inflow, potentially related to transport time to the offshore basin. Modeling results also indicate that the Mackenzie Delta has an influx of young but decadal material (20-30 years of age), pointing to the presence of an intermediate reservoir.

Overall, these results show that a significant fraction of vascular plant C undergoes pre-aging in terrestrial reservoirs prior to accumulation in deltaic and marine sediments. The age distribution, reflecting both storage and transport times, likely depends on landscape-specific factors such as local topography, hydrographic characteristics, and mean annual temperature of the catchment, all of which affect the degree of soil buildup and preservation. We show that catchment-specific carbon residence times across landscapes can vary by an order of magnitude, with important implications both for carbon cycle studies and for the interpretation of molecular terrestrial paleoclimate records preserved in sedimentary sequences.},
	keywords = {british-columbia, CARIACO BASIN, compound-specific radiocarbon, MACKENZIE DELTA, marine-sediments, odp leg 169s, saanich inlet, SANTA-MONICA BASIN, SOIL ORGANIC-MATTER, TROPICAL VEGETATION},
	issn = {00167037},
	doi = {10.1016/j.gca.2018.09.034},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0016703718305702https://api.elsevier.com/content/article/PII:S0016703718305702?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0016703718305702?httpAccept=text/plain},
	author = {Vonk, Jorien E. and Drenzek, Nicholas J. and Hughen, Konrad A. and Stanley, Rachel H.R. and McIntyre, Cameron and {\c c}on, Daniel B. and Giosan, Liviu and Southon, John R. and Santos, Guaciara M. and Druffel, Ellen R.M. and Andersson, August A. and {\"o}ld, Martin and Eglinton, Timothy I.}
}
@article {317,
	title = {A new look at old carbon in active margin sediments RID F-1809-2010},
	journal = {Geology},
	volume = {37},
	year = {2009},
	note = {id: 1987; PT: J; UT: WOS:000263842200012},
	pages = {239-242},
	abstract = {Recent studies suggest that as much as half of the organic carbon (OC) undergoing burial in the sediments of tectonically active continental margins may be the product of fossil shale weathering. These estimates rely on the assumption that vascular plant detritus spends little time sequestered in intermediate reservoirs such as soils, freshwater sediments, and river deltas, and thus only minimally contributes to the extraneously old (14)C ages of total organic matter often observed on adjacent shelves. Here we test this paradigm by measuring the (14)C and delta(13)C values of individual higher plant wax fatty acids as well as the d13C values of extractable alkanes isolated from the Eel River margin (California). The isotopic signatures of the long chain fatty acids indicate that vascular plant material has been sequestered for several thousand years before deposition. A coupled molecular isotope mass balance used to reassess the sedimentary carbon budget indicates that the fossil component is less abundant than previously estimated, with pre-aged terrestrial material instead composing a considerable proportion of all organic matter. If these findings are characteristic of other continental margins proximal to small mountainous rivers, then the importance of petrogenic OC burial in marine sediments may need to be reevaluated.},
	issn = {0091-7613},
	doi = {10.1130/G25351A.1},
	author = {Drenzek, Nicholas J. and Hughen, Konrad A. and Montlu{\c c}on, Daniel B. and Southon, John R. and dos Santos, Guaciara M. and Druffel, Ellen R. M. and Giosan, Liviu and Eglinton, Timothy I.}
}
@article {1907,
	title = {Constraints on the origin of sedimentary organic carbon in the Beaufort Sea from coupled molecular 13C and 14C measurements},
	journal = {Marine Chemistry},
	volume = {103},
	year = {2007},
	note = {id: 1030},
	month = {2007},
	pages = {146-162},
	author = {Drenzek, Nicholas J. and Montlu{\c c}on, Daniel B. and Yunker, Mark B. and Macdonald, Robie W. and Eglinton, Timothy I.}
}
