@article {1897,
	title = {Aging of marine organic matter during cross-shelf lateral transport in the Benguela upwelling system revealed by compound-specific radiocarbon dating},
	journal = {Geochemistry Geophysics Geosystems},
	volume = {8},
	year = {2007},
	note = {213qvTimes Cited:3
Cited References Count:60
},
	month = {Sep 18},
	abstract = {Organic matter accumulation and burial on the Namibian shelf and upper slope are spatially heterogeneous and strongly controlled by lateral transport in subsurface nepheloid layers. Much of the material deposited in depo-centers on the slope ultimately derives from the shelf. Supply of organic matter from the shelf involves selective transport of organic matter. We studied these selective transport processes by analyzing the radiocarbon content of co-occurring sediment fractions. Here we present radiocarbon data for total organic carbon as well as three tracers of surface ocean productivity (phytoplankton-derived alkenones, membrane lipids of pelagic crenarchaeota (crenarchaeol), and calcareous microfossils of planktic foraminifera) in core-top and near-surface sediment samples. The samples were collected on the Namibian margin along a shelf-slope transect (85 to 1040 m) at 24 degrees S and from the upper slope depo-center at 25.5 degrees S. In core-top sediments, alkenone ages gradually increased from modern to 3490 radiocarbon years with distance from shore and with water depth. Crenarchaeol, while younger than alkenones, also increased in age with distance offshore. It was concluded that the observed ages were a consequence of cross-shelf transport and associated aging of organic matter. Radiocarbon ages of preserved lipid biomarkers in sediments thus at least partially depend on the relative amount of laterally supplied, pre-aged material present in a sample, highlighting the importance of nepheloid transport for the sedimentation of organic matter over the Namibian margin.},
	keywords = {alkenones, atlantic-ocean, burial, carbon accumulation, coastal, compound-specific radiocarbon dating, continental-margin, ionization mass-spectrometry, membrane-lipids, namibia, sea sediments, Sediment transport},
	isbn = {1525-2027},
	doi = {10.1029/2007GC001603},
	author = {Mollenhauer, G. and Inthorn, M. and Vogt, T. and Zabel, M. and Damste, J. S. S. and Eglinton, T. I.}
}
@article {1899,
	title = {Diagenetic and sedimentological controls on the composition of organic matter preserved in California Borderland Basin sediments},
	journal = {Limnology and Oceanography},
	volume = {52},
	year = {2007},
	note = {149kgTimes Cited:43
Cited References Count:67
},
	month = {Mar},
	pages = {558-576},
	abstract = {Compound-specific radiocarbon (C-14) contents, stable carbon isotopes, and abundances of phytoplankton and vascular plant derived lipid biomarkers (alkenones and fatty acids) were obtained from Santa Barbara Basin and Santa Monica Basin sediments, along with radiocarbon contents of planktic foraminifera and total organic carbon. We investigated core-top and prebomb sediment intervals at sites from the flanks and depocenters of the basins deposited under contrasting bottom water oxygen concentrations. Bulk organic matter generally has the lowest radiocarbon levels of all sediment constituents measured, whereas planktic foraminifera tend to be the most radiocarbon enriched. Alkenones are systematically depleted in radiocarbon with respect to foraminifera. Short-chain (C-14, C-16, C-18) fatty acids decrease rapidly in absolute abundance and relative to longer-chain (> C-24) homologues from core-top to prebomb samples. The loss of short-chain fatty acids with depth is associated with C-13 depletion of short-chain fatty acids, indicating preferential preservation of terrestrially derived fatty acids. Short-chain fatty acids tend to be more C-14-enriched relative to alkenones in core-top sediments, whereas longer-chain homologues are generally the most radiocarbon depleted of the lipids studied here. Less refractory compounds (e.g., short-chain fatty acids) are thus enriched in radiocarbon with respect to more recalcitrant biomarkers (alkenones, long-chain fatty acids). The lower C-14 content of more refractory compounds reflects a larger proportion of laterally supplied, preaged material. Greater preservation of labile organic compounds observed at the depocenters than in flank sediments results in the presence of "younger" biomarkers, underlining the important influence of selective degradation of labile compounds on their radiocarbon ages.},
	keywords = {c-14 measurements, compound-specific radiocarbon, continental-margin, fatty-acids, marine-sediments, monica basin, oxic degradation, oxygen exposure time, santa-barbara basin, surface sediments},
	isbn = {0024-3590},
	doi = {10.4319/lo.2007.52.2.0558},
	author = {Mollenhauer, G. and Eglinton, T. I.}
}
@article {1958,
	title = {Sediment Cd and Mo accumulation in the oxygen-minimum zone off western Baja California linked to global climate over the past 52 kyr},
	journal = {Paleoceanography},
	volume = {21},
	year = {2006},
	note = {110idTimes Cited:34
Cited References Count:68
},
	month = {Nov 25},
	abstract = {[ 1] Concentrations of organic carbon (orgC), cadmium (Cd), and molybdenum (Mo) were measured in two sediment cores raised from depths of 430 and 700 m within the oxygen-minimum zone (OMZ) off southern Baja California at a temporal resolution of similar to 0.5 kyr over the past 52 kyr. These records are supplemented with diffuse spectral reflectance (DSR) measurements obtained on board ship soon after collection at a resolution of similar to 0.05 kyr. In the core from 700 m depth, a component extracted from the DSR data and the three geochemical proxies generally vary in concert with each other and over a wide range ( 4 - 22\% orgC; 1 - 40 mg/kg Cd; 5 120 mg/kg Mo). Intervals of increased orgC, Cd, and Mo accumulation generally correspond to warm periods recorded in the oxygen-isotopic composition of Greenland ice, with the exception of the Bolling/Allerod which is only weakly expressed off Baja California. Concentrations of the biogenic proxies are higher in the core from 430 m depth, but erratic sediment accumulation before 15 ka precludes dating of the older intervals that are laminated and contain elevated orgC, Cd, and Mo concentrations. The new data provide further evidence of an intimate teleconnection between global climate and the intensity of the OMZ and/or productivity along the western margin of North America. On the basis of a comparison with Cd and Mo records collected elsewhere in the region, we conclude that productivity may actually have varied off southern Baja California by no more than a factor of 2 over the past 52 kyr.},
	keywords = {continental-margin, enhanced preservation, late pleistocene, marine-sediments, nitrogen isotope, northeast pacific waters, organic-carbon preservation, productivity variations, santa-barbara basin, suboxic sediments},
	isbn = {0883-8305},
	doi = {10.1029/2005PA001239},
	author = {Dean, W. E. and Zheng, Y. and Ortiz, J. D. and van Geen, A.}
}
