Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2009 Jul 14;106(28):11651-6.
doi: 10.1073/pnas.0811793106. Epub 2009 Jun 26.

Subseafloor sedimentary life in the South Pacific Gyre

Steven D'Hondt  1 , Arthur J Spivack, Robert Pockalny, Timothy G Ferdelman, Jan P Fischer, Jens Kallmeyer, Lewis J Abrams, David C Smith, Dennis Graham, Franciszek Hasiuk, Heather Schrum, Andrea M Stancin
Affiliations

Subseafloor sedimentary life in the South Pacific Gyre

Steven D'Hondt et al. Proc Natl Acad Sci U S A. .

Abstract

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 H(2) 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.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Fig. 1.
Fig. 1.
Site locations on a map of time-averaged sea-surface chl-a concentrations [Global SeaWiFS Chlorophyll (mean of September 1997–December 2004)]. White dots mark sites analyzed for this study. Black dots mark sites previously analyzed for subseafloor biomass and/or activity (2, 3). Dashed white lines delimit the area in each gyre where the sea-surface chlorophyll-a (chl-a) concentration is ≤0.14 mg/m3.
Fig. 2.
Fig. 2.
Cell concentrations in subseafloor sediment. White dots mark data from SPG sites SPG-1 to SPG-11, and white triangles mark data from site SPG-12, just outside the gyre (this study). Black dots mark data from all other sites (2, 3).
Fig. 3.
Fig. 3.
Dissolved chemical concentrations in subseafloor sediment of the SPG sites: O2 (Left), NO3−(Center), and alkalinity (Right).
See this image and copyright information in PMC

References

    1. Whelan J, et al. Evidence for sulfate-reducing and methane-producing microorganisms in sediments from Sites 618, 619, and 622. In: Bouma AH, et al., editors. Initial Reports Deep Sea Drilling Project 96. Washington: U.S. Government Printing Office; 1986. pp. 767–775.
    1. Parkes RJ, Cragg BA, Wellsbury P. Recent studies on bacterial populations and processes in subseafloor sediments: A review. Hydrogeology J. 2000;8:11–28.
    1. D'Hondt S, et al. Distributions of microbial activities in deep subseafloor sediments. Science. 2004;306:2216–2221. - PubMed
    1. Jørgensen BB, D'Hondt SL, Miller DJ. Leg 201 synthesis: Controls on microbial communities in deeply buried sediments. In: Jørgensen BB, D'Hondt SL, Miller DJ, editors. Proceedings Ocean Drilling Program, Scientific Results, 201; College Station, TX: Ocean Drilling Program; 2006. pp. 1–45.
    1. Jahnke RA. The global ocean flux of particulate organic carbon: Areal distribution and magnitude. Global Biogeochem Cycles. 1996;10:71–88.

Publication types

LinkOut - more resources