Burial of organic carbon and pyrite sulfur in the modern ocean: its geochemical and environmental significance

Journal Article · Thu Apr 01 04:00:00 EST 1982 · Am. J. Sci.; (United States)

DOI:https://doi.org/10.2475/ajs.282.4.451· OSTI ID:5137265

Berner, R A

It is possible to estimate the present-day rate of burial of organic carbon in marine sediments from a knowledge of the suspended load carried by rivers and the organic carbon content of resultant deltaic-shelf sediments. This is done here for a number of the world's major rivers. Extrapolation of results to all remaining rivers indicates that the total burial rate of organic carbon in shelf-deltaic muds is 130 Mt (megatons = 10/sup 12/ gm) of carbon per y. This value is decidedly lower than the rate by which organic carbon is added to the oceans by rivers, which indicates that continentally-derived organic matter must undergo appreciable biological decomposition in the marine environment. The low carbon burial also indicates that much less than 10 percent of the missing anthropogenic CO/sub 2/ produced over the past 100 yrs is present as organic carbon in marine sediments. The average organic carbon concentration calculated from this data for modern terrigenous muds is lower than that found for ancient shales, and this can be best explained in terms of dilution of carbon in modern sediments by excess river-borne mineral matter resulting from man-induced soil erosion or Pleistocene continental glaciation. The worldwide burial rate of pyritic sulfur in marine sediments, 39 Mt S per y, is obtained by dividing the organic carbon burial rate in anoxic, terrigenous, fine-grained sediments by the constant ratio of C/S found, at depth, in such sediments. The average concentration of pyrite sulfur in modern muds (0.22 percent) is somewhat lower than that estimated for ancient shales (0.35 percent), and this can be best explained in terms of dilution of the sulfur in modern muds by river-borne silicate mineral matter, from glaciation or soil erosion, in the same manner as hypothesized for organic carbon.

• Research Organization: Yale Univ., New Haven, CT
• OSTI ID: 5137265
• Journal Information: Am. J. Sci.; (United States), Journal Name: Am. J. Sci.; (United States) Vol. 282; ISSN AJSCA
• Country of Publication: United States
• Language: English

Related Subjects

520200* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
CARBON
CARBON CYCLE
CHALCOGENIDES
CONTINENTAL MARGIN
CONTINENTAL SHELF
ECOLOGICAL CONCENTRATION
ELEMENTS
ENVIRONMENTAL TRANSPORT
GLOBAL ASPECTS
IRON COMPOUNDS
IRON SULFIDES
MASS TRANSFER
MINERAL CYCLING
MINERALS
NONMETALS
ORGANIC MATTER
PYRITE
RIVERS
SEAS
SEDIMENTS
STREAMS
SULFIDE MINERALS
SULFIDES
SULFUR
SULFUR COMPOUNDS
SURFACE WATERS
TRANSITION ELEMENT COMPOUNDS