Measurements of the U₃₇ K’ index and the absolute abundance of alkenones in marine sediments are increasingly used in paleoceanographic research as proxies of past sea surface
temperature and haptophyte (mainly coccolith-bearing species) primary productivity, respectively. An
important aspect of these studies is to be able to compare reliably data...
Recent works have investigated use of the hydrogen isotopic composition of C₃₇ alkenones (δD[subscript K37s]), lipid biomarkers of certain haptophyte microalgae, as an independent paleosalinity proxy. I discuss herein the factors impeding such an application and identify the potential alternative use of δD[subscript K37s] measurements as a proxy for non-thermal,...
Lipid biomarkers in sediments are widely used to infer environmental conditions that have
occurred in the geological past, but these reconstructions require a careful consideration of the
biotic and abiotic processes that degrade and alter the lipid biomarker compositions before
and after deposition. In this paper, we use alkenones produced...
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applications. A review. 8
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J.-F. Rontani
a
, J.K. Volkman
b
, F.G. Prahl
c
, S.G. Wakeham
d
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Simulations of past climates require altered
boundary conditions to account for known shifts in the Earth
system. For the Last Glacial Maximum (LGM) and subsequent
deglaciation, the existence of large Northern Hemisphere
ice sheets caused profound changes in surface topography
and albedo. While ice-sheet extent is fairly well
known, numerous...
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Ullman, D. J., LeGrande, A. N., Carlson, A. E., Anslow, F. S., and Licciardi, J. M.:
Assessing the
We reconstructed oxygenation changes in the Oxygen Minimum Zone of the upwelling ecosystem off Concepción (36° S), Chile, using inorganic and organic proxies in a sediment core covering the last ca. 110 years of sedimentation in this area. Authigenic enrichments of Mo, U and Cd were observed between ca. 1935–1971...
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., Pantoja, S., Sepúlveda, J., Lange, C. B., Muñoz, P., Summons, R. E.,
McKay, J., and Salamanca, M. (2015
We reconstructed oxygenation changes in the upwelling ecosystem off Concepción (36° S), Chile, using inorganic and organic proxies in a sediment core covering the last ca. 110 years of sedimentation in this area. Authigenic enrichments of Mo, U and Cd were observed between ca. 1935 and 1971 CE, implying a...
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., Sepúlveda, J., Lange, C. B., Muñoz, P., Summons, R. E.,
McKay, J., & Salamanca, M. (2015). Interdecadal
Oxidized intervals of five organic‐rich Madeira Abyssal Plain (MAP) turbidites deposited during the Miocene, Pliocene, and Pleistocene all displayed comparable major loss of total organic carbon (TOC) (84 ± 3.1%) accompanied by a negative isotopic (δ¹³C) shift ranging from −0.3 to −2.9‰. Major but significantly lower loss of total nitrogen...
A three-part study was conducted into the impact of physiological and ecological variables on the net isotopic fractionation of hydrogen, α[subscript K₃₇], expressed in C₃₇ alkenones. First, alkenone-producer production, abundance, and export were characterized in the summertime Gulf of California and Eastern Tropical North Pacific using compound-specific, labeled in situ...
The East and West Coyote Hills in the eastern Los Angeles Basin are the surface expression of uplift accompanying blind reverse faulting. Folded Quaternary strata indicate that the hills are growing and that the faults underlying them are active. Detailed subsurface mapping in the East Coyote Oil Field shows that...
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...