The influence of organic matter diagenesis on CaCO[sub 3] dissolution at the deep-sea floor

Journal Article · Fri Jul 01 04:00:00 EDT 1994 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(94)90115-5· OSTI ID:6723712

Jahnke, R A; Craven, D B ^[1]; Gaillard, J F ^[2]

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1. Skidaway Institute of Oceanography, Savannah, GA (United States)
2. Univ. of Notre Dame, IN (United States)

In situ benthic flux chamber measurements were performed at seafloor locations in the Atlantic and Pacific oceans where the bottomwaters were supersaturated, approximately saturated, and undersaturated with respect to calcite. There was no evidence of significant dissolution at or above the saturation horizon. Below the saturation horizon, however, significant benthic fluxes of titration alkalinity and calcium out of the sediments were observed indicating appreciable dissolution. Where observed, the rate of dissolution is consistent with a rate expression of reaction order 4.5 and a rate constant in the range of 0.05 to 0.5% per day. A numerical simulation was constructed to represent organic matter and CaCO[sub 3] diagenesis at the seafloor. At the supersaturated and near-saturation sites, the model over-predicts the influence of metabolically produced CO[sub 2] on the extent of CaCO[sub 3] dissolution. It is possible that these results can be reconciled by a better understanding and parameterization of organic matter mineralization and porewater transport processes in surface sediments. The primary factors to be considered include (1) the oxidation state of the carbon being oxidized, (2) the vertical distribution of oxidation rates including the role of DOC in sediment mineralization, (3) the influence of nondiffusive transport of near-surface porewaters, and (4) the influence of episodic depositional events on organic and inorganic carbon cycling.

• OSTI ID: 6723712
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Journal Name: Geochimica et Cosmochimica Acta; (United States) Vol. 58:13; ISSN GCACAK; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540320* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (1990-)
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATES
CHEMICAL COMPOSITION
DIAGENESIS
DISSOLUTION
MATHEMATICAL MODELS
MATTER
ORGANIC MATTER
OXYGEN COMPOUNDS
PALEOCLIMATOLOGY
PALEONTOLOGY
SEDIMENTS