@article {2961,
	title = {Persistence of old soil carbon under changing climate: The role of mineral-organic matter interactions},
	journal = {Chemical Geology},
	volume = {587},
	year = {2022},
	month = {Jan-01-2022},
	pages = {120629},
	abstract = {Globally, soils store between 1500 and 2800 Pg of organic carbon (OC). The physical and chemical stability of these terrestrial soil carbon stores under plausible climate change scenarios is unclear. Soil organic carbon (SOC), especially in volcanic soils, is stabilized through mineral matrix interactions. How susceptible are these mineral-organic matter interactions to environmental change? Here we present a study of SOC age along a climate gradient of andisols from Kohala volcano on the Island of Hawai{\textquoteright}i. We measure carbon isotope composition (14C/12C, 13C/12C) in bulk samples and extracted biomarkers for 4{\textendash}8 horizons of 15 soil profiles to understand variability in SOC age and persistence across incremental differences in mean annual precipitation. Bulk OC in the subsoil has radiocarbon fraction modern (Fm) values as low as 0.28 to 0.16 (~10,160 to ~14,630 conventional radiocarbon years). Coexisting plant-derived long chain fatty acids (LCFAs) are older, over 22,500 yrs. (Fm = 0.060), implying that these are among the most stable compounds in the soil, while corresponding shorter-chain (C16) fatty acids are much younger, consistent with an origin from active microbial communities assimilating young OC percolating from surface horizons. There is significant Fe loss at higher mean annual precipitation (MAP) (>2200 mm yr-1) sites associated with episodic soil saturation and microbial Fe reduction. \%OC is higher at these sites, consistent with the expectation that saturated conditions promote SOC storage. However, in these higher MAP sites iron depletion is associated with much younger bulk SOC and LCFAs 14C ages (~2900 14C years) than at equivalent sample depths in sites that retain most Fe (~14,200 14C years). The remaining mineral matrix consists primarily of Si, Al, and Ti as SRO minerals. The data imply that modest increases in precipitation resulting from environmental change at locations near a potential saturation or redox threshold could result in destabilization of Fe-SOC complexes, rendering previously stabilized carbon available for rapid degradation, potentially irreversibly decreasing the size of the old SOC reservoir. The destabilization of an old, persistent Fe-SOC reservoir can decrease SOC storage and ultimately increase the amount of CO2 released to the atmosphere.},
	issn = {00092541},
	doi = {10.1016/j.chemgeo.2021.120629},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0009254121005726},
	author = {Grant, Katherine E. and Galy, Valier V. and Haghipour, Negar and Eglinton, Timothy I. and Derry, Louis A.}
}
@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 {2764,
	title = {Mineral protection regulates long-term global preservation of natural organic carbon},
	journal = {Nature},
	volume = {570},
	year = {2019},
	month = {Jan-06-2019},
	pages = {228 - 231},
	abstract = {The balance between photosynthetic organic carbon production and respiration controls atmospheric composition and climate1,2. The majority of organic carbon is respired back to carbon dioxide in the biosphere, but a small fraction escapes remineralization and is preserved over geological timescales3. By removing reduced carbon from Earth{\textquoteright}s surface, this sequestration process promotes atmospheric oxygen accumulation2 and carbon dioxide removal1. Two major mechanisms have been proposed to explain organic carbon preservation: selective preservation of biochemically unreactive compounds4,5 and protection resulting from interactions with a mineral matrix6,7. Although both mechanisms can operate across a range of environments and timescales, their global relative importance on 1,000-year to 100,000-year timescales remains uncertain4. Here we present a global dataset of the distributions of organic carbon activation energy and corresponding radiocarbon ages in soils, sediments and dissolved organic carbon. We find that activation energy distributions broaden over time in all mineral-containing samples. This result requires increasing bond-strength diversity, consistent with the formation of organo-mineral bonds8 but inconsistent with selective preservation. Radiocarbon ages further reveal that high-energy, mineral-bound organic carbon persists for millennia relative to low-energy, unbound organic carbon. Our results provide globally coherent evidence for the proposed7 importance of mineral protection in promoting organic carbon preservation. We suggest that similar studies of bond-strength diversity in ancient sediments may reveal how and why organic carbon preservation{\textemdash}and thus atmospheric composition and climate{\textemdash}has varied over geological time.},
	issn = {0028-0836},
	doi = {10.1038/s41586-019-1280-6},
	url = {http://www.nature.com/articles/s41586-019-1280-6},
	author = {Hemingway, Jordon D. and Rothman, Daniel H. and Grant, Katherine E. and Rosengard, Sarah Z. and Eglinton, Timothy I. and Derry, Louis A. and Galy, Valier V.}
}
@article { ISI:000476997800003,
	title = {MULTI-SUBSTRATE RADIOCARBON DATA CONSTRAIN DETRITAL AND RESERVOIR EFFECTS IN HOLOCENE SEDIMENTS OF THE GREAT SALT LAKE, UTAH},
	journal = {RADIOCARBON},
	volume = {61},
	number = {4},
	year = {2019},
	month = {AUG},
	pages = {905-926},
	abstract = {The radiocarbon (C-14) content of simultaneously deposited substrates in lacustrine archives may differ due to reservoir and detrital effects, complicating the development of age models and interpretation of proxy records. Multi-substrate C-14 studies quantifying these effects remain rare, however, particularly for large, terminal lake systems, which are excellent recorders of regional hydroclimate change. We report C-14 ages of carbonates, brine shrimp cysts, algal mat biomass, total organic carbon (TOC), terrestrial macrofossils, and n-alkane biomarkers from Holocene sediments of the Great Salt Lake (GSL), Utah. C-14 ages for co-deposited aquatic organic substrates are generally consistent, with small offsets that may reflect variable terrestrial organic matter inputs to the system. Carbonates and long-chain n-alkanes derived from vascular plants, however, are similar to 1000-4000 C-14 years older than other substrates, reflecting deposition of pre-aged detrital materials. All lacustrine substrates are C-14-depleted compared to terrestrial macrofossils, suggesting that the reservoir age of the GSL was > 1200 years throughout most of the Holocene, far greater than the modern reservoir age of the lake (similar to 300 years). These results suggest good potential for multi-substrate paleoenvironmental reconstruction from Holocene GSL sediments but point to limitations including reservoir-induced uncertainty in( 14)C chronologies and attenuation and time-shifting of some proxy signals due to detrital effects.},
	issn = {0033-8222},
	doi = {10.1017/RDC.2019.62},
	author = {Bowen, Gabriel J. and Nielson, Kristine E. and Eglinton, Timothy I.}
}
@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 {2757,
	title = {Significance of Perylene for Source Allocation of Terrigenous Organic Matter in Aquatic SedimentsSignificance of Perylene for Source Allocation of Terrigenous Organic Matter in Aquatic Sediments},
	journal = {Environmental Science \& Technology},
	volume = {53},
	year = {2019},
	month = {Apr-07-2020},
	pages = {8244 - 8251},
	abstract = {Perylene is a frequently abundant, and sometimes the only polycyclic aromatic hydrocarbon (PAH) in aquatic sediments, but its origin has been subject of a longstanding debate in geochemical research and pollutant forensics because its historical record differs markedly from typical anthropogenic PAHs. Here we investigate whether perylene serves as a source-specific molecular marker of fungal activity in forest soils. We use a well-characterized sedimentary record (1735-1999) from the anoxic-bottom waters of the Pettaquamscutt River basin, RI to examine mass accumulation rates and isotope records of perylene, and compare them with total organic carbon and the anthropogenic PAH fluoranthene. We support our arguments with radiocarbon (14C) data of higher plant leaf-wax n-alkanoic acids. Isotope-mass balance-calculations of perylene and n-alkanoic acids indicate that \~{}40\% of sedimentary organic matter is of terrestrial origin. Further, both terrestrial markers are pre-aged on millennial time-scales prior to burial in sediments and are insensitive to elevated 14C concentrations following nuclear weapons testing in the mid-20th Century. Instead, changes coincide with enhanced erosional flux during urban sprawl. These findings suggest that perylene is definitely a product of soil-derived fungi, and a powerful chemical tracer to study the spatial and temporal connectivity between terrestrial and aquatic environments. },
	issn = {0013-936X},
	doi = {10.1021/acs.est.9b0234410.1021/acs.est.9b02344.s001},
	url = {https://pubs.acs.org/doi/10.1021/acs.est.9b02344},
	author = {Hanke, Ulrich M. and Lima-Braun, Ana L. and Eglinton, Timothy I. and Donnelly, Jeffrey P. and Galy, Valier and Poussart, Pascale and Hughen, Konrad and McNichol, Ann P. and Xu, Li and Reddy, Christopher M.}
}
@article {2642,
	title = {Temporal constraints on lateral organic matter transport along a coastal mud belt},
	journal = {Organic Geochemistry},
	volume = {128},
	year = {2019},
	month = {Jan-02-2019},
	pages = {86 - 93},
	abstract = {Constraints on timescales of lateral transport of sedimentary organic carbon (OC) over continental shelves and associated influences on the distribution and abundance of OC remain sparse. Preferential degradation of labile, young OC during lateral transport results in apparent {\textquotedblleft}diagenetic aging{\textquotedblright} of OC. Additionally, sediment translocation can also result in {\textquotedblleft}transport time-associated aging{\textquotedblright} of associated organic matter (OM) as a function of the lateral transport time (LTT). Here, we use a coupled thermal decomposition and radiocarbon (14C) approach to constrain timescales of lateral transport and concomitant loss of OC associated with different grain size fractions of sediments collected from two locations \~{}275 km apart along a dispersal pathway on the inner shelf of the East China Sea. The 14C age contrasts between corresponding thermal fractions are used to distinguish these two components of sedimentary OM {\textquotedblleft}aging{\textquotedblright}. To minimize interferences from hydrodynamic sorting and diagenetic aging of OC accompanying lateral transport, we assess 14C age differences of decomposition products from the most thermally-refractory OC components associated with specific grain size fractions between locations. We show that LTTs vary among different grain size fractions, and examine relationships between LTTs and sedimentary OC loss in order to assess the decomposition of OC as a consequence of lateral transport. We suggest that the decomposition of OC associated with protracted lateral transport exerts a strong influence on OC burial efficiency, with broad implications for carbon cycling over continental shelves.},
	keywords = {14C aging, Continental shelf seas, East China Sea, Mud belt, organic matter, Sediment resuspension},
	issn = {01466380},
	doi = {10.1016/j.orggeochem.2019.01.007},
	url = {https://www.sciencedirect.com/science/article/pii/S0146638019300075},
	author = {Bao, Rui and Zhao, Meixun and McNichol, Ann and Galy, Valier and McIntyre, Cameron and Haghipour, Negar and Eglinton, Timothy I.}
}
@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 {2707,
	title = {A long-term decrease in the persistence of soil carbon caused by ancient Maya land use},
	journal = {Nature Geoscience},
	volume = {11},
	year = {2018},
	month = {Jan-09-2018},
	pages = {645 - 649},
	abstract = {The long-term effects of deforestation on tropical forest soil carbon reservoirs are important for estimating the consequences of land use on the global carbon cycle, but are poorly understood. The Maya Lowlands of Mexico and Guatemala provide a unique opportunity to assess this question, given the widespread deforestation by the ancient Maya that began ~4,000 years ago. Here, we compare radiocarbon ages of plant waxes and macrofossils in sediment cores from three lakes in the Maya Lowlands to record past changes in the mean soil transit time of plant waxes (MTTwax). MTTwax indicates the average age of plant waxes that are transported from soils to lake sediments, and comparison of radiocarbon data from soils and lake sediments within the same catchment indicates that MTTwax reflects the age of carbon in deep soils. All three sediment cores showed a decrease in MTTwax, ranging from 2,300 to 800 years, over the past 3,500 years. This decrease in MTTwax, indicating shorter storage times for carbon in lake catchment soils, is associated with evidence for ancient Maya deforestation. MTTwax never recovered to pre-deforestation values, despite subsequent reforestation, implying that current tropical deforestation will have long-lasting effects on soil carbon sinks.},
	issn = {1752-0894},
	doi = {10.1038/s41561-018-0192-7},
	url = {https://www.researchgate.net/publication/327119047_A_long-term_decrease_in_the_persistence_of_soil_carbon_caused_by_ancient_Maya_land_use},
	author = {Douglas, Peter M. J. and Pagani, Mark and Eglinton, Timothy I. and Brenner, Mark and Curtis, Jason H. and Breckenridge, Andy and Johnston, Kevin}
}
@article {2763,
	title = {Microbial oxidation of lithospheric organic carbon in rapidly eroding tropical mountain soils},
	journal = {Science},
	volume = {360},
	year = {2018},
	month = {Jan-04-2019},
	pages = {209 - 212},
	abstract = {Lithospheric organic carbon ({\textquotedblleft}petrogenic{\textquotedblright}; OCpetro) is oxidized during exhumation and subsequent erosion of mountain ranges. This process is a considerable source of carbon dioxide (CO2) to the atmosphere over geologic time scales, but the mechanisms that govern oxidation rates in mountain landscapes are poorly constrained. We demonstrate that, on average, 67 {\textpm} 11\% of the OCpetro initially present in bedrock exhumed from the tropical, rapidly eroding Central Range of Taiwan is oxidized in soils, leading to CO2 emissions of 6.1 to 18.6 metric tons of carbon per square kilometer per year. The molecular and isotopic evolution of bulk OC and lipid biomarkers during soil formation reveals that OCpetro remineralization is microbially mediated. Rapid oxidation in mountain soils drives CO2 emission fluxes that increase with erosion rate, thereby counteracting CO2 drawdown by silicate weathering and biospheric OC burial.},
	issn = {0036-8075},
	doi = {10.1126/science.aao6463},
	url = {https://www.sciencemag.org/lookup/doi/10.1126/science.aao6463},
	author = {Hemingway, Jordon D. and Hilton, Robert G. and Hovius, Niels and Eglinton, Timothy I. and Haghipour, Negar and Wacker, Lukas and Chen, Meng-Chiang and Galy, Valier V.}
}
@article {2692,
	title = {Organic Carbon Aging During Across-Shelf Transport},
	journal = {Geophysical Research Letters},
	volume = {45},
	year = {2018},
	month = {Apr-08-2020},
	pages = {8425 - 8434},
	abstract = {Compound-specific radiocarbon analysis (CSRA) was performed on different grain-size fractions of surficial sediments to examine and compare lateral transport times (LTTs) of organic carbon. 14C aging of long-chain leaf wax fatty acids along two dispersal pathways of fluvially-derived material on adjacent continental margins implies LTTs over distances of ~30 to 500 km that range from hundreds to thousands of years. The magnitude of aging differs among grain size fractions. Our finding suggests that LTTs vary both temporally and spatially as a function of the specific properties of different continental shelf settings. Observations suggest that 14C aging is widespread during lateral transport over continental shelves, with hydrodynamic particle sorting inducing age variations among organic components residing in different grain sizes. Consideration of these phenomena is of importance for understanding carbon cycle processes and interpretation on sedimentary records on continental margins.},
	issn = {0094-8276},
	doi = {10.1029/2018GL078904},
	url = {https://core.ac.uk/download/pdf/222887698.pdf},
	author = {Bao, Rui and Uchida, Masao and Zhao, Meixun and Haghipour, Negar and Montlucon, Daniel and McNichol, Ann and Wacker, Lukas and Hayes, John M. 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 {2604,
	title = {Tectonically-triggered sediment and carbon export to the Hadal zone},
	journal = {Nature Communications},
	volume = {9},
	year = {2018},
	month = {Jan-12-2018},
	abstract = {Sediments in deep ocean trenches may contain crucial information on past earthquake history
and constitute important sites of carbon burial. Here we present 14C data on bulk organic
carbon (OC) and its thermal decomposition fractions produced by ramped pyrolysis/oxidation
for a core retrieved from the >7.5 km-deep Japan Trench. High-resolution 14C measurements,
coupled with distinctive thermogram characteristics of OC, reveal hemipelagic
sedimentation interrupted by episodic deposition of pre-aged OC in the trench. Low δ13C
values and diverse 14C ages of thermal fractions imply that the latter material originates from
the adjacent margin, and the co-occurrence of pre-aged OC with intervals corresponding to
known earthquake events implies tectonically triggered, gravity-flow-driven supply. We show
that 14C ages of thermal fractions can yield valuable chronological constraints on sedimentary
sequences. Our findings shed new light on links between tectonically driven sedimentological
processes and marine carbon cycling, with implications for carbon dynamics in hadal
environments.},
	issn = {2041-1723},
	doi = {10.1038/s41467-017-02504-1},
	url = {http://www.nature.com/articles/s41467-017-02504-1http://www.nature.com/articles/s41467-017-02504-1.pdfhttp://www.nature.com/articles/s41467-017-02504-1.pdfhttp://www.nature.com/articles/s41467-017-02504-1},
	author = {Bao, Rui and Strasser, Michael and McNichol, Ann P. and Haghipour, Negar and McIntyre, Cameron and Wefer, Gerold and Eglinton, Timothy I.}
}
@article {2602,
	title = {Biological and physical controls on the flux and characteristics of sinking particles on the Northwest Atlantic margin},
	journal = {Journal of Geophysical Research: Oceans},
	volume = {122},
	year = {2017},
	month = {Jan-06-2017},
	pages = {4539 - 4553},
	abstract = {Biogenic matter characteristics and radiocarbon contents of organic carbon (OC) were examined on sinking particle samples intercepted at
three nominal depths of 1000 m, 2000 m, and 3000 m (similar to 50 m above the seafloor) during a 3 year sediment trap program on the New England slope in the Northwest Atlantic. We have sought to characterize the sources of sinking particles in the context of vertical export of biogenic particles from the overlying water column and lateral supply of resuspended sediment particles from adjacent margin sediments. High aluminum (Al) abundances and low OC radiocarbon contents indicated contributions from resuspended sediment which was greatest at 3000 m but also significant at shallower depths. The benthic source (i.e., laterally supplied resuspended sediment) of opal appears negligible based on the absence of a correlation with Al fluxes. In comparison, CaCO3 fluxes at 3000 m showed a positive correlation with Al fluxes. Benthic sources accounted for 42 similar to 63\% of the sinking particle flux based on radiocarbon mass balance and the relationship between Al flux and CaCO3 flux. Episodic pulses of Al at 3000 m were significantly correlated with the near-bottom current at a nearby hydrographic mooring site, implying the importance of current variability in lateral particle transport. However, Al fluxes at 1000 m and 2000 m were coherent but differed from those at 3000 m, implying more than one mode of lateral supply of particles in the water column.},
	doi = {10.1002/jgrc.v122.610.1002/2016JC012549},
	url = {http://doi.wiley.com/10.1002/jgrc.v122.6http://doi.wiley.com/10.1002/2016JC012549http://onlinelibrary.wiley.com/wol1/doi/10.1002/2016JC012549/fullpdfhttps://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002\%2F2016JC012549},
	author = {Hwang, Jeomshik and Manganini, Steven J. and Park, JongJin and {\c c}on, Daniel B. and Toole, John M. and Eglinton, Timothy I.}
}
@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 {2805,
	title = {What on Earth Have We Been Burning? Deciphering Sedimentary Records of Pyrogenic CarbonWhat on Earth Have We Been Burning? Deciphering Sedimentary Records of Pyrogenic Carbon},
	journal = {Environmental Science \& Technology},
	volume = {51},
	year = {2017},
	month = {Jul-11-2017},
	pages = {12972 - 12980},
	abstract = {Humans have interacted with fire for thousands of years, yet the utilization of fossil fuels marked the beginning of a new era. Ubiquitous in the environment, pyrogenic carbon (PyC) arises from incomplete combustion of biomass and fossil fuels, forming a continuum of condensed aromatic structures. Here, we develop and evaluate 14C records for two complementary PyC molecular markers, benzene polycarboxylic acids (BPCAs) and polycyclic aromatic hydrocarbons (PAHs), preserved in aquatic sediments from a suburban and a remote catchment in the United States (U.S.) from the mid-1700s to 1998. Results show that the majority of PyC stems from local sources and is transferred to aquatic sedimentary archives on subdecadal to millennial time scales. Whereas a small portion stems from near-contemporaneous production and sedimentation, the majority of PyC (\~{}90\%) experiences delayed transmission due to {\textquotedblleft}preaging{\textquotedblright} on millennial time scales in catchment soils prior to its ultimate deposition. BPCAs (soot) and PAHs (precursors of soot) trace fossil fuel-derived PyC. Both markers parallel historical records of the consumption of fossil fuels in the U.S., yet never account for more than 19\% total PyC. This study demonstrates that isotopic characterization of multiple tracers is necessary to constrain histories and inventories of PyC and that sequestration of PyC can markedly lag its production.},
	issn = {0013-936X},
	doi = {10.1021/acs.est.7b03243},
	url = {https://pubs.acs.org/doi/10.1021/acs.est.7b03243},
	author = {Hanke, Ulrich M. and Reddy, Christopher M. and Braun, Ana L. L. and Coppola, Alysha I. and Haghipour, Negar and McIntyre, Cameron P. and Wacker, Lukas and Xu, Li and McNichol, Ann P. and Abiven, Samuel and Schmidt, Michael W. I. and Eglinton, Timothy I.}
}
@article {1280,
	title = {Arctic Deltaic Lake Sediments As Recorders of Fluvial Organic Matter Deposition},
	volume = {4},
	year = {2016},
	month = {2016},
	pages = {77},
	abstract = {Arctic deltas are dynamic and vulnerable regions that play a key role in land-ocean interactions and the global carbon cycle. Delta lakes may provide valuable historical records of the quality and quantity of fluvial fluxes, parameters that are challenging to investigate in these remote regions. Here we study lakes from across the Mackenzie Delta, Arctic Canada, that receive fluvial sediments from the Mackenzie River when spring flood water levels rise above natural levees. We compare downcore lake sediments with suspended sediments collected during the spring flood, using bulk (\% organic carbon, \% total nitrogen, 13C, 14C) and molecular organic geochemistry (lignin, leaf waxes). High-resolution age models (137Cs, 210Pb) of downcore lake sediment records (n=11) along with lamina counting on high-resolution radiographs show sediment deposition frequencies ranging between annually to every 15 years. Down-core geochemical variability in a representative delta lake sediment core is consistent with historical variability in spring flood hydrology (variability in peak discharge, ice jamming, peak water levels). Comparison with earlier published Mackenzie River depth profiles shows that (i) lake sediments reflect the riverine surface suspended load, and (ii) hydrodynamic sorting patterns related to spring flood characteristics are reflected in the lake sediments. Bulk and molecular geochemistry of suspended particulate matter from the spring flood peak and lake sediments are relatively similar showing a mixture of modern higher-plant derived material, older terrestrial permafrost material, and old rock-derived material. This suggests that deltaic lake sedimentary records hold great promise as recorders of past (century-scale) riverine fluxes and may prove instrumental in shedding light on past behaviour of arctic rivers, as well as how they respond to a changing climate.},
	isbn = {2296-6463},
	doi = {10.3389/feart.2016.00077},
	url = {http://journal.frontiersin.org/article/10.3389/feart.2016.00077},
	author = {Vonk, Jorien E. and Dickens, Angela F. and Giosan, Liviu and Hussain, Zainab A. and Kim, Bokyung and Zipper, Samuel C. and Holmes, Robert M. and Montlu{\c c}on, Daniel B. and Galy, Valier and Eglinton, Timothy I.}
}
@article {2573,
	title = {Historical records of organic matter supply and degradation status in the East Siberian Sea},
	journal = {Organic Geochemistry},
	volume = {91},
	year = {2016},
	month = {Jan-01-2016},
	pages = {16 - 30},
	abstract = {Destabilization and degradation of permafrost carbon in the Arctic regions could constitute a positive feedback to climate change. A better understanding of its fate upon discharge to the Arctic shelf is therefore needed. In this study, bulk carbon isotopes as well as terrigenous and marine biomarkers were used to construct two centennial records in the East Siberian Sea. Differences in topsoil and Pleistocene Ice Complex Deposit permafrost concentrations, modeled using δ13C and Δ14C, were larger between inner and outer shelf than the changes over time. Similarly, lignin-derived phenol and cutin acid concentrations differed by a factor of ten between the two stations, but did not change significantly over time, consistent with the dual-carbon isotope model. High molecular weight (HMW) n-alkane and n-alkanoic acid concentrations displayed a smaller difference between the two stations (factor of 3{\textendash}6). By contrast, the fraction for marine OC drastically decreased during burial with a half-life of 19{\textendash}27 years. Vegetation and degradation proxies suggested supply of highly degraded gymnosperm wood tissues. Lipid Carbon Preference Index (CPI) values indicated more extensively degraded HMW n-alkanes on the outer shelf with no change over time, whereas n-alkanoic acids appeared to be less degraded toward the core top with no large differences between the stations. Taken together, our results show larger across-shelf changes than down-core trends. Further investigation is required to establish whether the observed spatial differences are due to different sources for the two depositional settings or, alternatively, a consequence of hydrodynamic sorting combined with selective degradation during cross-shelf transport.},
	keywords = {210Pb, Arctic, East Siberian Arctic Shelf, HMW wax lipids, Lignin, Monte Carlo, δ13C, Δ14C},
	issn = {01466380},
	doi = {10.1016/j.orggeochem.2015.10.008},
	url = {https://doi.org/10.1016/j.orggeochem.2015.10.008},
	author = {Broder, Lisa and Tesi, Tommaso and Andersson, August and Eglinton, Timothy I. and Semiletov, Igor P. and Dudarev, Oleg V. and Roos, Per and Gustafsson, ?rjan}
}
@article { ISI:000389875700005,
	title = {RAPID C-14 ANALYSIS OF DISSOLVED ORGANIC CARBON IN NON-SALINE WATERS},
	journal = {RADIOCARBON},
	volume = {58},
	number = {{3}},
	year = {2016},
	month = {SEP},
	pages = {505-515},
	type = {Article},
	abstract = {The radiocarbon content of dissolved organic carbon (DOC) in rivers, lakes, and other non-saline waters can provide valuable information on carbon cycling dynamics in the environment. DOC is typically prepared for C-14 analysis by accelerator mass spectrometry (AMS) either by ultraviolet (UV) oxidation or by freeze-drying and sealed tube combustion. We present here a new method for the rapid analysis of C-14 of DOC using wet chemical oxidation (WCO) and automated headspace sampling of CO2. The approach is an adaption of recently developed methods using aqueous persulfate oxidant to determine the delta C-13 of DOC in non-saline water samples and the C-14 content of volatile organic acids. One advantage of the current method over UV oxidation is higher throughput: 22 samples and 10 processing standards can be prepared in one day and analyzed in a second day, allowing a full suite of C-14 processing standards and blanks to be run in conjunction with samples. A second advantage is that there is less potential for cross-contamination between samples.},
	keywords = {carbon-cycling, dissolved organic carbon, method development, wet chemical oxidation},
	issn = {0033-8222},
	doi = {10.1017/RDC.2016.17},
	author = {Lang, Susan Q. and McIntyre, Cameron P. and Bernasconi, Stefano M. and Fruh-Green, Gretchen L. and Voss, Britta M. and Eglinton, Timothy I. and Wacker, Lukas}
}
@article { ISI:000368907500001,
	title = {Multimolecular tracers of terrestrial carbon transfer across the pan-Arctic: C-14 characteristics of sedimentary carbon components and their environmental controls},
	journal = {GLOBAL BIOGEOCHEMICAL CYCLES},
	volume = {29},
	number = {{11}},
	year = {2015},
	month = {NOV},
	pages = {1855-1873},
	type = {Article},
	abstract = {Distinguishing the sources, ages, and fate of various terrestrial organic carbon (OC) pools mobilized from heterogeneous Arctic landscapes is key to assessing climatic impacts on the fluvial release of carbon from permafrost. Through molecular C-14 measurements, including novel analyses of suberin- and/or cutin-derived diacids (DAs) and hydroxy fatty acids (FAs), we compared the radiocarbon characteristics of a comprehensive suite of terrestrial markers (including plant wax lipids, cutin, suberin, lignin, and hydroxy phenols) in the sedimentary particles from nine major arctic and subarctic rivers in order to establish a benchmark assessment of the mobilization patterns of terrestrial OC pools across the pan-Arctic. Terrestrial lipids, including suberin-derived longer-chain DAs (C-24,C-26,C-28), plant wax FAs (C(24,26,2)8), and n-alkanes (C-27,C-29,C-31), incorporated significant inputs of aged carbon, presumably from deeper soil horizons. Mobilization and translocation of these {\textquoteleft}{\textquoteleft}old{{\textquoteright}{\textquoteright}} terrestrial carbon components was dependent on nonlinear processes associated with permafrost distributions. By contrast, shorter-chain (C-16,C-18) DAs and lignin phenols (as well as hydroxy phenols in rivers outside eastern Eurasian Arctic) were much more enriched in C-14, suggesting incorporation of relatively young carbon supplied by runoff processes from recent vegetation debris and surface layers. Furthermore, the radiocarbon content of terrestrial markers is heavily influenced by specific OC sources and degradation status. Overall, multitracer molecular C-14 analysis sheds new light on the mobilization of terrestrial OC from arctic watersheds. Our findings of distinct ages for various terrestrial carbon components may aid in elucidating fate of different terrestrial OC pools in the face of increasing arctic permafrost thaw.},
	issn = {0886-6236},
	doi = {10.1002/2015GB005204},
	author = {Feng, Xiaojuan and Gustafsson, {\"O}rjan and Holmes, R. Max and Vonk, Jorien E. and van Dongen, Bart E. and Semiletov, Igor P. and Dudarev, Oleg V. and Yunker, Mark B. and Macdonald, Robie W. and Wacker, Lukas and Montlu{\c c}on, Daniel B. and Eglinton, Timothy I.}
}
@article {2585,
	title = {Indonesian vegetation response to changes in rainfall seasonality over the past 25,000 years},
	journal = {Nature Geoscience},
	volume = {7449278721172063253871891072011563523665412739429544323},
	year = {2014},
	month = {Jan-06-2014},
	pages = {513 - 517},
	abstract = {The hydrologic response to climate forcing in the Indo-Pacific warm pool region has varied spatially over the past 25,000 years1, 2, 3, 4, 5. For example, drier conditions are inferred on Java and Borneo for the period following the end of the Last Glacial Maximum, whereas wetter conditions are reconstructed for northwest Australia4. The response of vegetation to these past rainfall variations is poorly constrained. Using a suite of 30 surface marine sediment samples from throughout the Indo-Pacific warm pool, we demonstrate that today the stable isotopic composition of vascular plant fatty acids (δ13Cfa) reflects the regional vegetation composition. This in turn is controlled by the seasonality of rainfall consistent with dry season water stress6. Applying this proxy in a sediment core from offshore northeast Borneo, we show broadly similar vegetation cover during the Last Glacial Maximum and the Holocene, suggesting that, despite generally drier glacial conditions1, 7, there was no pronounced dry season. In contrast, δ13Cfa and pollen data from a core off the coast of Sumba indicate an expansion of C4 herbs during the most recent glaciation, implying enhanced aridity and water stress during the dry season. Holocene vegetation trends are also consistent with a response to dry season water stress. We therefore conclude that vegetation in tropical monsoon regions is susceptible to increases in water stress arising from an enhanced seasonality of rainfall, as has occurred8 in past decades.},
	keywords = {Palaeoclimate, Palaeoecology},
	issn = {1752-0894},
	doi = {10.1038/ngeo2182},
	url = {http://www.nature.com/doifinder/10.1038/ngeo2182},
	author = {Dubois, Nathalie and Oppo, Delia W. and Galy, Valier V. and Mohtadi, Mahyar and van der Kaars, Sander and Tierney, Jessica E. and Rosenthal, Yair and Eglinton, Timothy I. and L?ckge, Andreas and Linsley, Braddock K.}
}
@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}
}
@article {108,
	title = {14C and 13C characteristics of higher plant biomarkers in Washington margin surface sediments},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {105},
	year = {2013},
	note = {id: 2267},
	pages = {14-30},
	abstract = {Plant wax lipids and lignin phenols are the two most common classes of molecular markers that are used to trace vascular plant-derived OM in the marine environment. However, their 13C and 14C compositions have not been directly compared, which can be used to constrain the flux and attenuation of terrestrial carbon in marine environment. In this study, we describe a revised method of isolating individual lignin phenols from complex sedimentary matrices for 14C analysis using high pressure liquid chromatography (HPLC) and compare this approach to a method utilizing preparative capillary gas chromatography (PCGC). We then examine in detail the 13C and 14C compositions of plant wax lipids and lignin phenols in sediments from the inner and mid shelf of the Washington margin that are influenced by discharge of the Columbia River. Plant wax lipids (including n-alkanes, n-alkanoic (fatty) acids, n-alkanols, and n-aldehydes) displayed significant variability in both δ13C (-28.3{\textperthousand} to -37.5{\textperthousand}) and Δ14C values (-204{\textperthousand} to +2{\textperthousand}), suggesting varied inputs and/or continental storage and transport histories. In contrast, lignin phenols exhibited similar δ13C values (between -30{\textperthousand} and -34{\textperthousand}) and a relatively narrow range of Δ14C values (-45{\textperthousand} to -150{\textperthousand}; HPLC-based measurement) that were similar to, or younger than, bulk OM (-195{\textperthousand} to -137{\textperthousand}). Moreover, lignin phenol 14C age correlated with the degradation characteristics of this terrestrial biopolymer in that vanillyl phenols were on average \~{}500 years older than syringyl and cinnamyl phenols that degrade faster in soils and sediments. The isotopic characteristics, abundance, and distribution of lignin phenols in sediments suggest that they serve as promising tracers of recently biosynthesized terrestrial OM during supply to, and dispersal within the marine environment. Lignin phenol 14C measurements may also provide useful constraints on the vascular plant end member in isotopic mixing models for carbon source apportionment, and for interpretation of sedimentary records of past vegetation dynamics.},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2012.11.034},
	url = {http://www.sciencedirect.com/science/article/pii/S0016703712006874},
	author = {Feng, Xiaojuan and Benitez-Nelson, Bryan C. and Montlu{\c c}on, Daniel B. and Prahl, Fredrick G. and McNichol, Ann P. and Xu, Li and Repeta, Daniel J. and Eglinton, Timothy I.}
}
@article { ISI:000315194800002,
	title = {C-14 and C-13 characteristics of higher plant biomarkers in Washington margin surface sediments},
	journal = {GEOCHIMICA ET COSMOCHIMICA ACTA},
	volume = {105},
	year = {2013},
	month = {MAR 15},
	pages = {14-30},
	type = {Article},
	abstract = {Plant wax lipids and lignin phenols are the two most common classes of molecular markers that are used to trace vascular plant-derived OM in the marine environment. However, their C-13 and C-14 compositions have not been directly compared, which can be used to constrain the flux and attenuation of terrestrial carbon in marine environment. In this study, we describe a revised method of isolating individual lignin phenols from complex sedimentary matrices for C-14 analysis using high pressure liquid chromatography (HPLC) and compare this approach to a method utilizing preparative capillary gas chromatography (PCGC). We then examine in detail the C-13 and C-14 compositions of plant wax lipids and lignin phenols in sediments from the inner and mid shelf of the Washington margin that are influenced by discharge of the Columbia River. Plant wax lipids (including n-alkanes, n-alkanoic (fatty) acids, n-alkanols, and n-aldehydes) displayed significant variability in both delta C-13 (-28.3 parts per thousand to -37.5 parts per thousand) and Delta C-14 values (-204 parts per thousand to +2 parts per thousand), suggesting varied inputs and/or continental storage and transport histories. In contrast, lignin phenols exhibited similar delta C-13 values (between -30 parts per thousand and -34 parts per thousand) and a relatively narrow range of Delta C-14 values (-45 parts per thousand to -150 parts per thousand; HPLC-based measurement) that were similar to, or younger than, bulk OM (-195 parts per thousand to -137 parts per thousand). Moreover, lignin phenol C-14 age correlated with the degradation characteristics of this terrestrial biopolymer in that vanillyl phenols were on average similar to 500 years older than syringyl and cinnamyl phenols that degrade faster in soils and sediments. The isotopic characteristics, abundance, and distribution of lignin phenols in sediments suggest that they serve as promising tracers of recently biosynthesized terrestrial OM during supply to, and dispersal within the marine environment. Lignin phenol C-14 measurements may also provide useful constraints on the vascular plant end member in isotopic mixing models for carbon source apportionment, and for interpretation of sedimentary records of past vegetation dynamics. (C) 2012 Elsevier Ltd. All rights reserved.},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2012.11.034},
	author = {Feng, Xiaojuan and Benitez-Nelson, Bryan C. and Montlu{\c c}on, Daniel B. and Prahl, Fredrick G. and McNichol, Ann P. and Xu, Li and Repeta, Daniel J. and Eglinton, Timothy I.}
}
@article {101,
	title = {Molecular and isotopic insights into particulate organic carbon sources and dynamics in Jordan Basin, Gulf of Maine},
	journal = {Continental Shelf Research},
	volume = {68},
	year = {2013},
	pages = {15-22},
	abstract = {The carbon isotope and lipid biomarker composition of suspended particles and surface sediment was measured to examine the impact of sediment supply, redistribution and post-depositional alteration processes on organic matter cycling in the Gulf of Maine, a semi-enclosed shelf sea in the northwest Atlantic. A beam attenuation profile revealed a >50 m-thick benthic nepheloid layer (BNL) in the Jordan Basin at the time of sampling (April 2006). The relatively low radiocarbon content of suspended particulate organic carbon (POC) in the BNL indicates that up to 82\% of the POC in this layer was supplied from resuspension of sediment. The concentration of alkenones normalized to POC increased with increasing depth in the water column and was highest in the surface sediment. In contrast to these markers of surface ocean photoautotrophy, the vertical profiles for the concentration and composition of short-chain (C14{\textendash}C18) n-alkanoic acids provided evidence for enhanced heterotrophic processes near the top of the BNL. Suspended POC samples from two depths within the BNL exhibited marked differences in radiocarbon content and fatty acid composition, suggesting that biological activity and associated processes within the BNL are vertically heterogeneous.},
	issn = {0278-4343},
	doi = {10.1016/j.csr.2013.08.005},
	url = {http://www.sciencedirect.com/science/article/pii/S0278434313002653},
	author = {Hwang, Jeomshik and Montlu{\c c}on, Daniel B. and Pilskaln, Cynthia H. and Eglinton, Timothy I.}
}
@article { ISI:000309889600007,
	title = {Carbon isotopic (C-13 and C-14) composition of synthetic estrogens and progestogens},
	journal = {RAPID COMMUNICATIONS IN MASS SPECTROMETRY},
	volume = {26},
	number = {{22}},
	year = {2012},
	month = {NOV 30},
	pages = {2619-2626},
	type = {Article},
	abstract = {RATIONALE Steroids are potent hormones that are found in many environments. Yet, contributions from synthetic and endogenous sources are largely uncharacterized. The goal of this study was to evaluate whether carbon isotopes could be used to distinguish between synthetic and endogenous steroids in wastewater and other environmental matrices. METHODS Estrogens and progestogens were isolated from oral contraceptive pills using semi-preparative liquid chromatography/diode array detection (LC/DAD). Compound purity was confirmed by gas chromatography/flame ionization detection (GC/FID), gas chromatography/time-of-flight mass spectrometry (GC/TOF-MS) and liquid chromatography/mass spectrometry using negative electrospray ionization (LC/ESI-MS). The C-13 content was determined by gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and C-14 was measured by accelerator mass spectrometry (AMS). RESULTS Synthetic estrogens and progestogens are C-13-depleted (delta C-13(estrogen) = 30.0 +/- 0.9 parts per thousand; delta C-13(progestogen) = 30.3 +/- 2.6 parts per thousand) compared with endogenous hormones (delta C-13 similar to -16 to 26 parts per thousand). The C-14 content of the majority of synthetic hormones is consistent with synthesis from C-3 plant-based precursors, amended with {\textquoteleft}fossil{\textquoteright} carbon in the case of EE2 and norethindrone acetate. Exceptions are progestogens that contain an ethyl group at carbon position 13 and have entirely {\textquoteleft}fossil{\textquoteright} C-14 signatures. CONCLUSIONS Carbon isotope measurements have the potential to distinguish between synthetic and endogenous hormones in the environment. Our results suggest that C-13 could be used to discriminate endogenous from synthetic estrogens in animal waste, wastewater effluent, and natural waters. In contrast, C-13 and C-14 together may prove useful for tracking synthetic progestogens. Copyright (c) 2012 John Wiley \& Sons, Ltd.},
	issn = {0951-4198},
	doi = {10.1002/rcm.6385},
	author = {Griffith, David R. and Wacker, Lukas and Gschwend, Philip M. and Eglinton, Timothy I.}
}
@article {217,
	title = {A depositional history of particulate organic carbon in a floodplain lake from the lower Ob{\textquoteright} River, Siberia},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {75},
	year = {2011},
	note = {id: 2172},
	pages = {4796-4815},
	abstract = {Northern, high latitude soils have stored vast amounts of organic carbon (OC) in permafrost and peats for many millennia, however, climate change may mobilize and release this particulate OC (POC) to arctic rivers. Deltaic and floodplain lakes that receive fluvial sediments, primarily during the spring freshet, may provide records of such changes in riverine POC. Here, we examine properties of OC in a sediment core from a lake in the lower floodplain of the Ob{\textquoteright} River, west Siberia, to determine how the properties of OC deposited in this lake varied over many decades and to evaluate use of this sedimentary OC as a recorder of riverine POC load and properties. The core predates the most recent, dramatic changes in arctic climate and hence may serve as a benchmark against which to contrast future variations in fluvial POC discharge. Elemental, stable carbon and radiocarbon isotopic analyses, along with nuclear magnetic resonance (NMR) spectroscopy and molecular-level information (lignin phenol composition), indicate two major sources of OC to most of the sediments in this lake: plant-derived OC and algal-derived OC. However, a mixing model indicates that the nature and 14C content of these two sources change with depth in the sediment, resulting in three distinct layers: surface horizons, a {\textquotedblleft}high-OC{\textquotedblright} layer and {\textquotedblleft}mixing{\textquotedblright} horizons found above and below the high-OC layer. The plant-derived component is significantly aged throughout the core (14C ages of 1300{\textendash}3900 years) and appears to derive from primarily local, tundra sources, whereas the algal component is modern. Our analysis suggests that the usual mode of OC deposition, as exemplified by the {\textquotedblleft}mixing{\textquotedblright} and surface horizons, involved mixing of varying amounts of new algal production (35{\textendash}65\%) with aged permafrost- or peat-derived OC. This deposition was interrupted by an event, such as the collapse of a riverbank, which laid down the compositionally distinct {\textquotedblleft}high-OC{\textquotedblright} layer in which plant-derived OC mixes with aged mineral-soil-derived OC without clear input from algae. The relative amounts of the plant and algal components in the lake sediments appear to be controlled primarily by local hydrological conditions rather than by river-wide processes, suggesting that comparison of sediment records from multiple lakes within a floodplain will be important to assess changes in POC export by arctic rivers. However, the flux and nature of the higher plant-derived OC may carry important information on the sources and dynamics of OC stored within the drainage basin.},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2011.05.032},
	url = {http://www.sciencedirect.com/science/article/pii/S0016703711003085},
	author = {Dickens, Angela F. and Baldock, Jeff and Kenna, Timothy C. and Eglinton, Timothy I.}
}
@article {2549,
	title = {Radiocarbon and 230Th data reveal rapid redistribution and temporal changes in sediment focussing at a North Atlantic drift},
	journal = {Earth and Planetary Science Letters},
	volume = {301},
	year = {2011},
	month = {Jan-01-2011},
	pages = {373 - 381},
	abstract = {In locations of rapid sediment accumulation receiving substantial amounts of laterally transported material the timescales of transport and accurate quantification of the transported material are at the focus of intense research. Here we present radiocarbon data obtained on co-occurring planktic foraminifera, marine haptophyte biomarkers (alkenones) and total organic carbon (TOC) coupled with excess Thorium-230 (230Thxs) measurements on four sediment cores retrieved in 1649{\textendash}2879m water depth from two such high accumulation drift deposits in the Northeast Atlantic, Bj{\"o}rn and Gardar Drifts. While 230Thxs inventories imply strong sediment focussing, no age offsets are observed between planktic foraminifera and alkenones, suggesting that redistribution of sediments is rapid and occurs soon after formation of marine organic matter, or that transported material contains negligible amounts of alkenones. An isotopic mass balance calculation based on radiocarbon concentrations of co-occurring sediment components leads us to estimate that transported sediment components contain up to 12\% of fossil organic matter that is free of or very poor in alkenones, but nevertheless appears to consist of a mixture of fresh and eroded fossil material. Considering all available constraints to characterize transported material, our results show that although focussing factors calculated from bulk sediment 230Thxs inventories may allow useful approximations of bulk redeposition, they do not provide a unique estimate of the amount of each laterally transported sediment component. Furthermore, our findings provide evidence that the occurrence of lateral sediment redistribution alone does not always hinder the use of multiple proxies but that individual sediment fractions are affected to variable extents by sediment focussing. 

},
	issn = {0012821X},
	doi = {10.1016/j.epsl.2010.11.022},
	url = {http://linkinghub.elsevier.com/retrieve/pii/S0012821X1000717X},
	author = {Mollenhauer, Gesine and McManus, Jerry F. and Wagner, Thomas and McCave, I. Nick and Eglinton, Timothy I.}
}
@article { ISI:000286640400038,
	title = {Radiocarbon and Th-230 data reveal rapid redistribution and temporal changes in sediment focussing at a North Atlantic drift},
	journal = {EARTH AND PLANETARY SCIENCE LETTERS},
	volume = {301},
	number = {{1-2}},
	year = {2011},
	month = {JAN 3},
	pages = {373-381},
	type = {Article},
	abstract = {In locations of rapid sediment accumulation receiving substantial amounts of laterally transported material the timescales of transport and accurate quantification of the transported material are at the focus of intense research. Here we present radiocarbon data obtained on co-occurring planktic foraminifera, marine haptophyte biomarkers (alkenones) and total organic carbon (TOC) coupled with excess Thorium-230 (Th-230(xs)) measurements on four sediment cores retrieved in 1649-2879 m water depth from two such high accumulation drift deposits in the Northeast Atlantic, Bjorn and Gardar Drifts. While Th-230(xs), inventories imply strong sediment focussing, no age offsets are observed between planktic foraminifera and alkenones, suggesting that redistribution of sediments is rapid and occurs soon after formation of marine organic matter, or that transported material contains negligible amounts of alkenones. An isotopic mass balance calculation based on radiocarbon concentrations of co-occurring sediment components leads us to estimate that transported sediment components contain up to 12\% of fossil organic matter that is free of or very poor in alkenones, but nevertheless appears to consist of a mixture of fresh and eroded fossil material. Considering all available constraints to characterize transported material, our results show that although focussing factors calculated from bulk sediment Th-230(xs) inventories may allow useful approximations of bulk redeposition, they do not provide a unique estimate of the amount of each laterally transported sediment component. Furthermore, our findings provide evidence that the occurrence of lateral sediment redistribution alone does not always hinder the use of multiple proxies but that individual sediment fractions are affected to variable extents by sediment focussing. (C) 2010 Elsevier B.V. All rights reserved.},
	keywords = {alkenones, compound-specific radiocarbon dating, drift sediments, focussing factors, Th-230(xs)},
	issn = {0012-821X},
	doi = {10.1016/j.epsl.2010.11.022},
	author = {Mollenhauer, Gesine and McManus, Jerry F. and Wagner, Thomas and McCave, I. Nick and Eglinton, Timothy I.}
}
@article {314,
	title = {Postglacial changes in El Nino and La Nina behavior},
	journal = {Geology},
	volume = {38},
	year = {2010},
	note = {id: 1985; PT: J; UT: WOS:000273346200011},
	pages = {43-46},
	abstract = {Paleoclimate reconstructions suggest distinctive changes in the Ell Nino-Southern Oscillation (ENSO), the dominant mode of tropical climate variability, over the last glacial cycle and throughout the Holocene. However, to the best of our knowledge, no studies provide parallel reconstructions of warm (El Nino) and cold (La Nina) phase variability, thus precluding distinction between variations in ENSO activity and the mean state of the tropical Pacific. Here we provide the first such records, generated using molecular organic geochemical proxies in a sediment core from the Peru margin region. The opposing influences of El Nino and La Nina on coastal upwelling and phytoplankton community structure produce distinct sedimentary sterol records describing the evolution of each ENSO phase. We document changes in surface ocean productivity on the Peru margin over the past 16 ka that indicate enhanced La Nina-like conditions alone during deglaciation, but concomitant increases in both El Nino and La Nina activity during the past 2 ka. We propose that the preponderance of La Nina-like conditions prior to 11.5 ka reflects the influence of waning glacial boundary conditions. By contrast, warm and cold phase covariability during the late Holocene suggests centennial-scale changes in ENSO activity, rather than the Pacific mean state, driven by tropical insolation.},
	issn = {0091-7613},
	doi = {10.1130/G30366.1},
	author = {Makou, Matthew C. and Eglinton, Timothy I. and Oppo, Delia W. and Hughen, Konrad A.}
}
@article { ISI:000284192000011,
	title = {The radiocarbon age of organic carbon in marine surface sediments},
	journal = {GEOCHIMICA ET COSMOCHIMICA ACTA},
	volume = {74},
	number = {{23}},
	year = {2010},
	month = {DEC 1},
	pages = {6788-6800},
	type = {Article},
	abstract = {Long-term carbon cycling and climate change are strongly dependent on organic carbon (OC) burial in marine sediments. Radiocarbon ((14)C) has been widely used to constrain the sources, sinks, and processing of sedimentary OC. To elucidate the dominant controls on the radiocarbon content of total organic carbon ((14)C(TOC)) accumulating in surface sediments we construct a box model that predicts (14)C(TOC) in the sediment mixed layer (measured as fraction modern, Fm). Our model defines three distinct OC pools ({{\textquoteright}{\textquoteright}}degradable,{{\textquoteright}{\textquoteright}} {\textquoteleft}{\textquoteleft}semi-labile,{{\textquoteright}{\textquoteright}} and {\textquoteleft}{\textquoteleft}refractory{{\textquoteright}{\textquoteright}}) and assumes that (14)C(TOC) flux to sediments is exclusively derived from surface ocean primary productivity, and hence follows a {\textquoteleft}{\textquoteleft}generic{{\textquoteright}{\textquoteright}} surface ocean dissolved inorganic carbon (DIC) bomb curve. Model predictions are compared to a set of 75 surface sediment samples, which span a wide geographic range and reflect diverse water column and depositional conditions, and for which sedimentation rate and mixed-layer depth are well characterized. Our model overestimates the Fm value for a majority (65\%) of these sites, especially at shallow water depths and for sites characterized by depleted delta(13)C(TOC) values. The model is most sensitive to sedimentation rate and mixed-layer depth. Therefore, slight changes to these parameters can lead to a match between modeled and measured Fm values at many sites. Yet, in some cases, we find that measured Fm values cannot be simulated without large and unrealistic changes to sedimentation rate and mixed-layer depth. These results point to sources of pre-aged OC to surface sediments and implicate soil-derived terrestrial OC, reworked marine OC, and/or anthropogenic carbon as important components of the organic matter present in surface sediments. This approach provides a valuable framework within which to explore controls on sedimentary organic matter composition and carbon burial over a range of spatial and temporal scales. (C) 2010 Elsevier Ltd. All rights reserved.},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2010.09.001},
	author = {Griffith, David R. and Martin, William R. and Eglinton, Timothy I.}
}
@article {496,
	title = {Timescales of lateral sediment transport in the Panama Basin as revealed by radiocarbon ages of alkenones, total organic carbon and foraminifera},
	journal = {Earth and Planetary Science Letters},
	volume = {290},
	year = {2010},
	note = {id: 882Y},
	pages = {340-350},
	issn = {0012821X},
	doi = {10.1016/j.epsl.2009.12.030},
	author = {Kusch, Stephanie and Eglinton, Timothy I. and Mix, Alan C. and Mollenhauer, Gesine}
}
@article { ISI:000267640400001,
	title = {High-sensitivity measurement of diverse vascular plant-derived biomarkers in high-altitude ice cores},
	journal = {GEOPHYSICAL RESEARCH LETTERS},
	volume = {36},
	year = {2009},
	month = {JUL 3},
	type = {Article},
	abstract = {Semi-volatile organic compounds derived from burned and fresh vascular plant sources and preserved in high-altitude ice fields were detected and identified through use of recently developed analytical tools. Specifically, stir bar sorptive extraction and thermal desorption coupled with gas chromatography/time-of-flight mass spectrometry allowed measurement of multiple biomarkers in small sample volumes (<= 30 ml). Among other compounds of interest, several diterpenoids, which suggest inputs from conifers and conifer burning, were identified in post-industrial era and older Holocene ice from the Sajama site in the Bolivian Andes, but not in a glacial period sample, consistent with aridity changes. Differences in biomarker assemblages between sites support the use of these compounds as regionally constrained recorders of vegetation and climate change. This study represents the first application of these analytical techniques to ice core research and the first indication that records of vegetation fires may be reconstructed from diterpenoids in ice. Citation: Makou, M. C., L. G. Thompson, D. B. Montlucon, and T. I. Eglinton (2009), High-sensitivity measurement of diverse vascular plant-derived biomarkers in high-altitude ice cores, Geophys. Res. Lett., 36, L13501, doi: 10.1029/2009GL037643.},
	issn = {0094-8276},
	doi = {10.1029/2009GL037643},
	author = {Makou, Matthew C. and Thompson, Lonnie G. and Montlu{\c c}on, Daniel B. 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 {490,
	title = {Origins of archaeal tetraether lipids in sediments: Insights from radiocarbon analysis RID A-6723-2009},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {72},
	year = {2008},
	note = {id: 2051; PT: J; UT: WOS:000259107700010},
	pages = {4577-4594},
	abstract = {Understanding the supply and preservation of glycerol dibiphytanyl glycerol tetraethers (GDGTs) in marine sediments helps inform their use in paleoceanography. Compound-specific radiocarbon measurements of sedimentary alkenones from multiple environments have been used to gain insight into processes that affect U-37(K{\textquoteright}) paleotemperature reconstructions. Similar analyses are warranted to investigate how analogous processes affecting GDGTs impact TEX86 paleotemperatures. Here we present radiocarbon measurements on individual GDGTs from Bermuda Rise and Santa Monica Basin sediments and discuss the results in the context of previous studies of co-depositional alkenones and foraminifera. The C-14 contents of GDGTs and planktonic foraminifera in Bermuda Rise are very similar, suggesting a local source; and TEX86-derived temperatures agree more closely with foraminiferal temperatures than do U-37(K{\textquoteright}) temperatures. In contrast, GDGTs in Santa Monica Basin are depleted in C-14 relative to both alkenones and foraminifera, and TEX86 temperatures agree poorly with known surface water values. We propose three possible factors that could explain these results: (i) GDGTs may be labile relative to alkenones during advective transport through oxic waters; (ii) archaeal production deep in the water column may contribute C-14-depleted GDGTs to sediments; and (iii) some GDGTs also may derive from sedimentary archaeal communities. Each of these three processes is likely to occur with varying relative importance depending on geographic location. The latter two may help to explain why TEX86 temperature reconstructions from Santa Monica Basin do not appear to reflect actual sea surface temperatures. Terrigenous GDGTs are unlikely to be major contributors to Bermuda Rise or Santa Monica Basin sediments, based on values of the BIT index. The results also indicate that the crenarchaeol regioisomer is governed by processes different from other GDGTs. Individual measurements of the crenarchaeol regioisomer are significantly depleted in C-14 relative to co-occurring GDGTs, indicating an alternative origin for this compound that presently remains unknown. Re-examination of the contribution of crenarchaeol regioisomer to the TEX86 index shows that it is a significant influence on the sensitivity of temperature reconstructions. (C) 2008 Elsevier Ltd. All rights reserved.},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2008.06.021},
	author = {Shah, Sunita R. and Mollenhauer, Gesine and Ohkouchi, Naohiko and Eglinton, Timothy I. and Pearson, Ann}
}
@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.}
}
@article {2442,
	title = {Relationships between carbon isotopic composition and mode of binding of natural organic matter in selected marine sediments},
	volume = {38},
	year = {2007},
	month = {2007/11//},
	pages = {1824 - 1837},
	abstract = {We have investigated the relationships between radiocarbon (14C) and stable carbon (13C) isotopic composition and the different modes of binding of organic matter (OM) in surficial sediments selected from near-shore and continental margin sites that vary in terms of input and depositional conditions. To improve our understanding of the entire OM pool, isotopic analysis of sedimentary sub-fractions, as opposed to individual compounds, was performed. This was achieved by sequentially treating sediments via solvent extraction to examine unbound compounds, followed by saponification to cleave ester linked moieties. Isotopic analysis was performed on the bulk sediment and resulting residues. The molecular composition of the extracts was examined using gas chromatography/mass spectrometry (GC/MS) and the relative contributions of terrestrial and marine biomarkers were assessed. Radiocarbon abundances (Δ14C) of the bulk sediment reflect a mixture of modern, pre-aged and fossil carbon. Offsets in Δ14C between the bulk sediment and sediment residues demonstrate varying associations of these carbon pools. For the majority of sites, a negative offset between extracted (EX-RES) and saponified (SA-RES) sediment residues results from the removal of relatively 14C-rich material during saponification. Saponification extracts (SAEs) are mainly composed of short chain (n-C12 to n-C24) alkanoic acids with an even/odd dominance, indicating a predominantly marine algal or microbial source. This provides evidence for the protection of labile marine carbon by chemical binding. This study bridges the gap between molecular level and bulk OM analysis of marine sediments.},
	isbn = {0146-6380},
	doi = {10.1016/j.orggeochem.2007.07.008},
	url = {http://www.sciencedirect.com/science/article/pii/S0146638007001751},
	author = {White, Helen K. and Reddy, Christopher M. and Eglinton, Timothy I.}
}
@article {1898,
	title = {Selective degradation of organic compounds in sediments from the California Borderland Basins: evidence from compound specific Delta 14C and delta 13C analyses},
	journal = {Limnology and Oceanography},
	volume = {52},
	year = {2007},
	note = {id: 544},
	month = {2007},
	pages = {558-576},
	author = {Mollenhauer, Gesine and Eglinton, Timothy I.}
}
@conference {1601,
	title = {Cross-shelf lateral transport in the Benguela Upwelling System: Aging of marine organic matter in the benthic boundary layer},
	booktitle = {Ocean Sciences Meeting},
	year = {2006},
	note = {id: 545},
	month = {2006},
	address = {Honollulu, Hawaii USA},
	author = {Mollenhauer, Gesine and Inthorn, Maik and Zabel, Matthias and Damste, Jaap Sinninghe and Eglinton, Timothy I.}
}
@article {1934,
	title = {Diageneitc and sedimentological controls on the composition of organic matter preserved in California Borderland Basin sediments},
	journal = {Limnology \& Oceanography Paleoceanography, submitted},
	year = {2006},
	note = {id: 1705},
	month = {2006},
	author = {Mollenhauer, Gesine and Eglinton, Timothy I.}
}
@conference {1621,
	title = {Effects of differential degradation of marine organic compounds on preserved radiocarbon ages and biomarker-based SST reconstructions, Poster},
	booktitle = {EGU General Assembly},
	year = {2006},
	note = {id: 1072},
	month = {2006},
	address = {Vienna, Austria},
	author = {Mollenhauer, Gesine and Sinninghe, Jaap S. and Eglinton, Timothy I.}
}
@article {1933,
	title = {Rapid lateral particle transport in the Argentine Basin: Molecular 14C and 230Th evidence},
	journal = {Deep-Sea Research I},
	volume = {53},
	year = {2006},
	note = {id: 543},
	month = {2006},
	pages = {1224-1243},
	author = {Mollenhauer, Gesine and McManus, Jerry F. and Benthien, Albert and Muller, Peter J. and Eglinton, Timothy I.}
}
@article {1981,
	title = {An evaluation of 14C age relationships between co-occurring foraminifera, alkenones, and total organic carbon in continental margin sediments},
	journal = {Paleoceanography},
	volume = {20},
	year = {2005},
	note = {id: 492},
	month = {2005},
	pages = {1-12},
	author = {Mollenhauer, Gesine and Kienast, Markus and Lamy, Frank and Meggers, Helge and Schneider, Ralph R. and Hayes, John M. and Eglinton, Timothy I.}
}
@conference {1551,
	title = {Advective controls on the age of marine sedimentary organic matter},
	booktitle = {Gordon Research Conference Organic Geochemistry},
	year = {2004},
	note = {id: 1068},
	month = {2004},
	address = {Holderness School, New Hampshsire, USA},
	author = {Mollenhauer, Gesine and Eglinton, Timothy I. and Hayes, John M.}
}
@conference {1760,
	title = {Radiocarbon ages of marine bimarkers and co-occurring foraminifera: evidence for differential particle transport on continental margins, Poster},
	booktitle = {Eighth International Conference on Palaeoceanography},
	year = {2004},
	note = {id: 549},
	month = {2004},
	address = {Biarritz, France},
	author = {Mollenhauer, Gesine and Eglinton, Timothy I. and Hayes, John M. and Kienast, Markus and Lamy, Frank and Meggers, Helge and Schneider, Ralph R.}
}
@conference {1764,
	title = {Radiocarbon content of alkenones, foraminifera and bulk OC in oxic and anoxic sediments from the California Borderland Basins, Poster},
	booktitle = {Gordon Research Conference Organic Geochemistry},
	year = {2004},
	note = {id: 550},
	month = {2004},
	address = {Holderness School, New Hampshire, USA},
	author = {Mollenhauer, Gesine and Eglinton, Timothy I.}
}
@conference {1554,
	title = {Alkenone radiocarbon stratigraphy at high resolution continental margin sites},
	booktitle = {EGS-AGU-EUG Joint Assembly},
	year = {2003},
	note = {id: 1071},
	month = {2003},
	address = {Nice, France},
	author = {Mollenhauer, Gesine and Eglinton, Timothy I. and Freudenthal, Tim and Lamy, Frank}
}
@article {2075,
	title = {Asynchronous alkenone and foraminifera records from the Benguela Upwelling System},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {67},
	year = {2003},
	note = {id: 1067},
	month = {2003},
	pages = {2157-2171},
	author = {Mollenhauer, Gesine and Eglinton, Timothy I. and Ohkouchi, Naohiko and Schneider, Ralph R. and Muller, Peter J. and Grootes, Pieter M. and Rullkotter, Jurgen}
}
@conference {1594,
	title = {Compound specific radiocarbon dating of alkenones: methodological considerations and applications in paleoceanography},
	booktitle = {18th International Radiocarbon Conference},
	year = {2003},
	note = {id: 1070},
	month = {2003},
	address = {Wellington, New Zealand},
	author = {Mollenhauer, Gesine and Eglinton, Timothy I. and Schneider, Ralph R. and Meggers, Helge and Lamy, Frank and Ohkouchi, Nao and Hayes, John M.}
}
@conference {1761,
	title = {Radiocarbon ages of marine biomarkers and co-occurring foraminifera: evidence for differential particle transport on continental margins},
	booktitle = {AGU Fall Meeting 2003},
	year = {2003},
	note = {id: 1069},
	month = {2003},
	address = {San Francisco, USA},
	author = {Mollenhauer, Gesine and Eglinton, Timothy I. and Hayes, John M. and Keinast, Markus and Lamy, Frank and Meggers, Helge and Schneider, Ralph R.}
}
@conference {1765,
	title = {Radiocarbon dating of alkenones in sediments from the Namibian continental margin},
	booktitle = {European Geophysical Society, XXVII General Assembly},
	year = {2002},
	note = {id: 546},
	month = {2002},
	address = {Nice, France},
	author = {Mollenhauer, Gesine and Eglinton, Timothy I. and Ohkouchi, Nao and Grootes, Pieter M. and Muller, Peter J. and Rullkotter, Jurgen and Schneider, Ralph R.}
}
