Journal ArticleDOI
Interpretation of measured concentration profiles in sediment pore water
TLDR
In this article, a robust numerical procedure for biogeochemical interpretation and analysis of measured concentration profiles of solutes in sediment pore water has been developed, which involves finding a series of least square fits to the measured concentration profile, followed by comparisons of these fits through statistical F-testing.Abstract:
A robust numerical procedure for biogeochemical interpretation and analysis of measured concentration profiles of solutes in sediment pore water has been developed. Assuming that the concentration-depth profile represents a steady state, the rate of net production or consumption as a function of depth can be calculated, together with the flux across the sediment-water interface. Three kinds of vertical transport can be included in the analysis: molecular diffusion, bioturbation, and irrigation. The procedure involves finding a series of least square fits to the measured concentration profile, followed by comparisons of these fits through statistical F-testing. This approach leads to an objective selection of the simplest production-consumption profile that reproduces the concentration profile. Because the numerical procedure is optimized with respect to speed, one prediction can typically be done in a few minutes or less on a personal computer. The technique has been tested successfully against analytical solutions describing the transport and consumption of 0, in sediment pore water. In other tests, measured concentration profiles of O,, NO;, , NH:, and ZCO, have been interpreted using the new procedure.read more
Citations
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Journal ArticleDOI
Anaerobic ammonium oxidation by anammox bacteria in the Black Sea
Marcel M. M. Kuypers,A. Olav Sliekers,Gaute Lavik,Markus Schmid,Bo Barker Jørgensen,J. Gijs Kuenen,Jaap S. Sinninghe Damsté,Marc Strous,Mike S. M. Jetten +8 more
TL;DR: Evidence for bacteria that anaerobically oxidize ammonium with nitrite to N2 in the world's largest anoxic basin, the Black Sea is provided and anammox bacteria have been identified and directly linked to the removal of fixed inorganic nitrogen in the environment.
Journal ArticleDOI
Oxygen dynamics of marine sediments
TL;DR: A review of the current status on what we know about controls that interrelate with the O2 dynamics of marine sediments can be found in this article, where the authors present case studies from abyssal sediments to microbial phototrophic communities.
Journal ArticleDOI
Catastrophic ape decline in western equatorial Africa
Peter D. Walsh,Kate Abernethy,Magdalena Bermejo,Rene Beyers,Pauwel De Wachter,Marc Ella Akou,Bas Huijbregts,Daniel Idiata Mambounga,Andre Kamdem Toham,Annelisa M. Kilbourn,Sally A. Lahm,Stefanie Latour,Fiona Maisels,Fiona Maisels,Chrisitian Mbina,Yves Mihindou,Sosthéne Ndong Obiang,Ernestine Ntsame Effa,Malcolm Starkey,Malcolm Starkey,Paul Telfer,Marc Thibault,Caroline E. G. Tutin,Lee J. T. White,David Wilkie +24 more
TL;DR: Survey results conservatively indicate that ape populations in Gabon declined by more than half between 1983 and 2000, and gorillas and common chimpanzees should be elevated immediately to ‘critically endangered’ status.
Journal ArticleDOI
Electric currents couple spatially separated biogeochemical processes in marine sediment
Lars Peter Nielsen,Nils Risgaard-Petersen,Henrik Fossing,Peter Bondo Christensen,Mikio Sayama +4 more
TL;DR: Evidence is provided that electric currents running through defaunated sediment couple oxygen consumption at the sediment surface to oxidation of hydrogen sulphide and organic carbon deep within the sediment and suggests that the electric current was conducted by bacterial nanowires combined with pyrite, soluble electron shuttles and outer-membrane cytochromes.
Journal ArticleDOI
Prokaryotic cells of the deep sub-seafloor biosphere identified as living bacteria
Axel Schippers,Lev N. Neretin,Jens Kallmeyer,Timothy G. Ferdelman,Barry Andrew Cragg,Ronald John Parkes,Bo Barker Jørgensen +6 more
TL;DR: It is shown that a large fraction of the sub-seafloor prokaryotes is alive, even in very old (16 million yr) and deep (> 400 m) sediments.
References
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Journal ArticleDOI
A simplex method for function minimization
John A. Nelder,R. Mead +1 more
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Journal ArticleDOI
Diffusion of ions in sea water and in deep-sea sediments
Li Yuan-Hui,Sandra Gregory +1 more
TL;DR: The tracer diffusion coefficients of ions in deep-sea sediments, Dj,sed., can be related to Dj∗ by as mentioned in this paper, where θ is the tortuosity of the bulk sediment and a constant close to one.