Biogeochemical cycling in an organic-rich coastal marine basin: 11. The sedimentary cycling of dissolved, free amino acids

Journal Article · Thu Nov 01 04:00:00 EST 1990 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(90)90120-A· OSTI ID:6161843

Burdige, D J; Martens, C S ^[1]

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1. Univ. of North Carolina, Chapel Hill (USA)

In the anoxic sediments of Cape Lookout Bight, NC, concentrations of total dissolved free amino acids (TDFAAs) are highest near the sediment-water interface, and decrease to non-zero, asymptotic concentrations at depths greater than 20 cm. TDFAAs in the overlying waters are <1 {mu}M. Dissolved free amino acid (DFAA) profiles often show a secondary subsurface maximum in the region between the 1 and 5 mM sulfate isopleths. This phenomenon appears to be related to the transition in the sediments of this region from sulfate reduction to methanogenesis. A steady-state diagenetic model which quantifies the processes affecting DFAAs in these sediments yields rates of DFAA production and consumption that agree reasonably well with independent estimates of these quantities in Cape Lookout Bight and other anoxic marine sediments. The combined results of modelling pore water DFAA and sedimentary amino acid profiles indicate that significant exchange of amino acids occurs between the sediments and pore waters. These results demonstrate that the biogeochemistry of dissolved free amino acids in the pore waters of Cape Lookout Bight sediments is dominated by internal transformations (i.e. production from sedimentary amino acids, microbial remineralization, and reincorporation back into the sediments). There is some uncertainty in the magnitude of the flux of DFAAs across the sediment-water interface, although it appears to be of secondary importance when compared to the other sedimentary processes affecting DFAAs.

• OSTI ID: 6161843
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Journal Name: Geochimica et Cosmochimica Acta; (USA) Vol. 54:11; ISSN GCACA; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AMINO ACIDS
ATLANTIC OCEAN
BIOGEOCHEMISTRY
CARBOXYLIC ACIDS
CHEMICAL COMPOSITION
CHEMISTRY
DIAGENESIS
DISSOLUTION
FEDERAL REGION IV
GEOCHEMISTRY
GEOLOGIC MODELS
GROUND WATER
HYDROGEN COMPOUNDS
INTERFACES
INTERSTITIAL WATER
MINERAL CYCLING
NORTH AMERICA
NORTH CAROLINA
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PRECIPITATION
SEAS
SEDIMENT-WATER INTERFACES
SEPARATION PROCESSES
SURFACE WATERS
USA
WATER