Sources and relative reactivities of amino acids, neutral sugars, and lignin in an intermittently anoxic marice environment

Journal Article · Fri May 01 04:00:00 EDT 1992 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(92)90323-B· OSTI ID:6991673

Cowie, G L; Hedges, J I ^[1]; Calvert, S E ^[2]

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1. Univ. of Washington, Seattle (United States)
2. Univ. of British Columbia, Vancouver (Canada)

A sediment-trap sample, representing an annual average particle flux at 50 m in Saanich Inlet, British Columbia, was analyzed for its elemental, amino acid, neutral sugar, and lignin composition. The results uniformly indicate primarily marine organic matter sources for all samples, although relatively higher terrigenous contributions are evident in the sediments. The [delta][sup 13]C values of trap materials also point to primarily autochthonous particle fluxes. Comparison of annual average water-column fluxes to sediment accumulation rates indicates undersampling of sinking particles due to lateral sediment inputs at depth. The anoxic benthic interface appears to be an important site of diagenesis, and selective removal is observed both at compound-class and molecular levels. Preferential loss of marine organic material is indicated by the calculated [delta][sup 13]C value and biochemical composition of the substrate. Concentrations of all measured organic constituents decreased with depth in the uniformly varved 0-14 cm sediment interval, and suggest in situ degradation. Relative reactivities of the biochemical classes indicate a change in diagenetic substrate from that utilized above and at the benthic interface. With the exception of the amino acids, however, diagenesis is generally less selective in the sediments. Protein, polysaccharide, and lignin contributions to total organic carbon decrease from 37% in the sediment-trap sample to 22% at the bottom of the 0.14 cm sediment interval. These biochemicals represent over 40 and 50-60% of the degraded carbon and nitrogen, respectively, and thus are important nutrients for the benthic and water-column communities.

• OSTI ID: 6991673
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Journal Name: Geochimica et Cosmochimica Acta; (United States) Vol. 56:5; ISSN GCACAK; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AMINO ACIDS
BIOGEOCHEMISTRY
BRITISH COLUMBIA
CANADA
CARBOHYDRATES
CARBOXYLIC ACIDS
CHEMICAL COMPOSITION
CHEMISTRY
DEPOSITION
DEVELOPED COUNTRIES
DIAGENESIS
ECOLOGICAL CONCENTRATION
GEOCHEMISTRY
INTERFACES
LIGNIN
NORTH AMERICA
NUTRIENTS
ORGANIC ACIDS
ORGANIC COMPOUNDS
POLYSACCHARIDES
SACCHARIDES
SEDIMENT-WATER INTERFACES
SEDIMENTS
THERMODYNAMIC ACTIVITY