Subseafloor sedimentary life in the South Pacific Gyre

The low-productivity South Pacific Gyre (SPG) is Earth's largest oceanic province. Its sediment accumulates extraordinarily slowly (0.1–1 m per million years). This sediment contains a living community that is characterized by very low biomass and very low metabolic activity. At every depth in cored SPG sediment, mean cell abundances are 3 to 4 orders of magnitude lower than at the same depths in all previously explored subseafloor communities. The net rate of respiration by the subseafloor sedimentary community at each SPG site is 1 to 3 orders of magnitude lower than the rates at previously explored sites. Because of the low respiration rates and the thinness of the sediment, interstitial waters are oxic throughout the sediment column in most of this region. Consequently, the sedimentary community of the SPG is predominantly aerobic, unlike previously explored subseafloor communities. Generation of H2 by radiolysis of water is a significant electron-donor source for this community. The per-cell respiration rates of this community are about 2 orders of magnitude higher (in oxidation/reduction equivalents) than in previously explored anaerobic subseafloor communities. Respiration rates and cell concentrations in subseafloor sediment throughout almost half of the world ocean may approach those in SPG sediment.

[1]  T. Plank,et al.  Lithium isotopic composition of marine sediments , 2006 .

[2]  K. H. Wedepohl Handbook of Geochemistry , 1969 .

[3]  B. Jørgensen,et al.  Leg 201 Synthesis: Controls on microbial communities in deeply buried sediments , 2006 .

[4]  B. Jørgensen,et al.  Microelectrodes: Their Use in Microbial Ecology , 1986 .

[5]  R. Jahnke,et al.  The global ocean flux of particulate organic carbon: Areal distribution and magnitude , 1996 .

[6]  Scott Rutherford,et al.  Metabolic Activity of Subsurface Life in Deep-Sea Sediments , 2002, Science.

[7]  A. Mcintyre,et al.  Determination of organic carbon and nitrogen in marine sediments using the Carlo Erba NA-1500 analyzer , 1990 .

[8]  B. Jørgensen,et al.  Biogeographical distribution and diversity of microbes in methane hydrate-bearing deep marine sediments on the Pacific Ocean Margin. , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[9]  J. Hayes,et al.  Biological formation of ethane and propane in the deep marine subsurface , 2006, Proceedings of the National Academy of Sciences.

[10]  Lei Zhou,et al.  Cretaceous/Tertiary boundary of DSDP Site 596, South Pacific , 1991 .

[11]  Stephan C Schuster,et al.  Metagenomic signatures of the Peru Margin subseafloor biosphere show a genetically distinct environment , 2008, Proceedings of the National Academy of Sciences.

[12]  H. Claustre,et al.  Optical properties of the “clearest” natural waters , 2007 .

[13]  J. Amend,et al.  A thermodynamic assessment of energy requirements for biomass synthesis by chemolithoautotrophic micro‐organisms in oxic and anoxic environments , 2005 .

[14]  George L. Pickard,et al.  Descriptive Physical Oceanography: An Introduction , 1963 .

[15]  Franciszek Hasiuk,et al.  Subseafloor sedimentary life in the South Pacific Gyre , 2009, Proceedings of the National Academy of Sciences.

[16]  Gerald R. Dickens,et al.  Distributions of Microbial Activities in Deep Subseafloor Sediments , 2004, Science.

[17]  D. Fink,et al.  Radiocarbon dating and sedimentation rates for holocene-upper pleistocene sediments, eastern equatorial pacific and Peru continental margin , 2006 .

[18]  N. Mateer Cretaceous-Tertiary boundary , 1992 .

[19]  H. Schulz Quantification of Early Diagenesis: Dissolved Constituents in Marine Pore Water , 2000 .

[20]  R. M. Owen,et al.  Broad region of no sediment in the southwest Pacific Basin , 2006 .

[21]  J. Spinks,et al.  Introduction to Radiation Chemistry , 1964 .

[22]  A. Teske,et al.  Stratified Communities of Active Archaea in Deep Marine Subsurface Sediments , 2006, Applied and Environmental Microbiology.

[23]  Ingo Klimant,et al.  Fiber‐optic oxygen microsensors, a new tool in aquatic biology , 1995 .

[24]  David C. Smith,et al.  New cell extraction procedure applied to deep subsurface sediments , 2008 .

[25]  Richard L. Smith,et al.  Evidence for Sulfate-Reducing and Methane-Producing Microorganisms in Sediments from Sites 618, 619, and 622 , 1986 .

[26]  R. Dietmar Müller,et al.  Digital isochrons of the world's ocean floor , 1997 .

[27]  K. Hinrichs,et al.  Significant contribution of Archaea to extant biomass in marine subsurface sediments , 2008, Nature.

[28]  B. Jørgensen,et al.  Prokaryotic cells of the deep sub-seafloor biosphere identified as living bacteria , 2005, Nature.

[29]  H. Claustre,et al.  The Many Shades of Ocean Blue , 2003, Science.

[30]  Rika Anderson,et al.  Heterotrophic Archaea dominate sedimentary subsurface ecosystems off Peru. , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[31]  B. Jørgensen,et al.  Controls on Microbial Communities in Deeply Buried Sediments, Eastern Equatorial Pacific and Peru Margin , 2001 .

[32]  S. D’Hondt,et al.  Radiolytic hydrogen and microbial respiration in subsurface sediments. , 2007, Astrobiology.

[33]  Peter Blum,et al.  Physical properties handbook: a guide to the shipboard measurement of physical properties of deep-sea cores , 1997 .

[34]  R. Parkes,et al.  Recent studies on bacterial populations and processes in subseafloor sediments: A review , 2000 .

[35]  P. Wachter,et al.  Optical Properties of GdS,GdSe,GdTeamd LaS , 1974 .

[36]  T. Onstott,et al.  Radiolytic H2 in continental crust: Nuclear power for deep subsurface microbial communities , 2005 .

[37]  Charles H. Langmuir,et al.  The chemical composition of subducting sediment and its consequences for the crust and mantle , 1998 .

[38]  P. Price,et al.  Temperature dependence of metabolic rates for microbial growth, maintenance, and survival. , 2004, Proceedings of the National Academy of Sciences of the United States of America.

[39]  Joris M. Gieskes,et al.  CHEMICAL METHODS FOR INTERSTITIAL WATER ANALYSIS ABOARD JOIDES RESOLUTION OCEAN DRILLING PROGRAM TEXAS A&M UNIVERSITY Technical Note 15 , 1991 .