Author
Gary P. Klinkhammer
Other affiliations: University of Leeds, University of Cambridge, University of Rhode Island ...read more
Bio: Gary P. Klinkhammer is an academic researcher from Oregon State University. The author has contributed to research in topics: Hydrothermal circulation & Hydrothermal vent. The author has an hindex of 58, co-authored 101 publications receiving 13632 citations. Previous affiliations of Gary P. Klinkhammer include University of Leeds & University of Cambridge.
Papers published on a yearly basis
Papers
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TL;DR: Pore water profiles of total CO 2, pH, PO 3−4, NO − 3 plus NO − 2, SO 2− 4, S 2−, Fe 2+ and Mn 2+ have been obtained in cores from pelagic sediments of the eastern equatorial Atlantic under waters of moderate to high productivity as mentioned in this paper.
3,045 citations
TL;DR: In this article, it was shown that dissolution of manganese and iron oxides may be induced by the onset of sulfate reduction, which occurs relatively late in the diagenetic sequence.
618 citations
TL;DR: In this paper, the rare earth elements (REEs) were measured in pore waters of the upper ∼25 cm of sediment from one site off Peru and three sites on the California margin.
568 citations
TL;DR: The discovery of black smokers, massive sulphides and vent biota in the rift valley of the Mid-Atlantic Ridge demonstrates that this assemblage of hydrothermal phenomena is not limited to intermediate-to-fast-spreading oceanic ridges as mentioned in this paper.
Abstract: The discovery of black smokers, massive sulphides and vent biota in the rift valley of the Mid-Atlantic Ridge demonstrates that this assemblage of hydrothermal phenomena is not limited to intermediate-to-fast-spreading oceanic ridges. Hydrothermal exchange processes may thus be important at the ridges which extend through the Atlantic Ocean and western Indian Ocean, comprising more than half of the 55,000-km global length of seafloor spreading centres.
432 citations
TL;DR: In this paper, the first hydrothermal fluid samples collected along the slow-spreading Mid-Atlantic Ridge (MAR) are remarkably similar in composition and temperature to fluids collected on the East Pacific Rise (EPR), and they appear to be in equilibrium with a greenschist-facies mineral assemblage.
Abstract: The first hydrothermal fluid samples collected along the slow-spreading Mid-Atlantic Ridge (MAR) are remarkably similar in composition and temperature to fluids collected along the shallower, faster-spreading East Pacific Rise (EPR). The MAR fluids, like those from the EPR, appear to be in equilibrium with a greenschist-facies mineral assemblage. In contrast to the EPR, the more fractured nature of the MAR apparently allows fluids at one of the MAR sites to interact with weathered basalt.
416 citations
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TL;DR: This article evaluated subducting sediments on a global basis in order to better define their chemical systematics and to determine both regional and global average compositions, and then used these compositions to assess the importance of sediments to arc volcanism and crust-mantle recycling, and to re-evaluate the chemical composition of the continental crust.
2,973 citations
TL;DR: In this paper, a synthesis of the use of selected trace elements as proxies for reconstruction of paleoproductivity and paleoredox conditions is presented, and the combined used of U, V and Mo enrichments may allow suboxic environments to be distinguished from anoxic-euxinic ones.
2,708 citations
TL;DR: The physiological characteristics of Geobacter species appear to explain why they have consistently been found to be the predominant Fe(III)- and Mn(IV)-reducing microorganisms in a variety of sedimentary environments.
2,633 citations
TL;DR: This is the first demonstration that microorganisms can completely oxidize organic compounds with Fe(III) or Mn(IV) as the sole electron acceptor and that oxidation of organic matter coupled to dissimilatory Fe( III), Mn( IV), or Mn (IV) reduction can yield energy for microbial growth.
Abstract: A dissimilatory Fe(III)- and Mn(IV)-reducing microorganism was isolated from freshwater sediments of the Potomac River, Maryland. The isolate, designated GS-15, grew in defined anaerobic medium with acetate as the sole electron donor and Fe(III), Mn(IV), or nitrate as the sole electron acceptor. GS-15 oxidized acetate to carbon dioxide with the concomitant reduction of amorphic Fe(III) oxide to magnetite (Fe(3)O(4)). When Fe(III) citrate replaced amorphic Fe(III) oxide as the electron acceptor, GS-15 grew faster and reduced all of the added Fe(III) to Fe(II). GS-15 reduced a natural amorphic Fe(III) oxide but did not significantly reduce highly crystalline Fe(III) forms. Fe(III) was reduced optimally at pH 6.7 to 7 and at 30 to 35 degrees C. Ethanol, butyrate, and propionate could also serve as electron donors for Fe(III) reduction. A variety of other organic compounds and hydrogen could not. MnO(2) was completely reduced to Mn(II), which precipitated as rhodochrosite (MnCO(3)). Nitrate was reduced to ammonia. Oxygen could not serve as an electron acceptor, and it inhibited growth with the other electron acceptors. This is the first demonstration that microorganisms can completely oxidize organic compounds with Fe(III) or Mn(IV) as the sole electron acceptor and that oxidation of organic matter coupled to dissimilatory Fe(III) or Mn(IV) reduction can yield energy for microbial growth. GS-15 provides a model for how enzymatically catalyzed reactions can be quantitatively significant mechanisms for the reduction of iron and manganese in anaerobic environments.
2,233 citations
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TL;DR: The second edition of The Biomarker Guide as mentioned in this paper provides a comprehensive account of the role that biomarker technology plays both in petroleum exploration and in understanding Earth history and processes.
Abstract: The second edition of The Biomarker Guide is a fully updated and expanded version of this essential reference. Now in two volumes, it provides a comprehensive account of the role that biomarker technology plays both in petroleum exploration and in understanding Earth history and processes. Biomarkers and Isotopes in the Environment and Human History details the origins of biomarkers and introduces basic chemical principles relevant to their study. It discusses analytical techniques, and applications of biomarkers to environmental and archaeological problems. The Biomarker Guide is an invaluable resource for geologists, petroleum geochemists, biogeochemists, environmental scientists and archaeologists.
2,163 citations