Organic matter accumulation, diagenesis and burial in a rapidly depositing coastal sediment

Conference · Wed Jan 01 04:00:00 EST 1992 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:6000311

Martens, C S ^[1]; Canuel, E A ^[2]

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1. Univ. of North Carolina, Chapel Hill, NC (United States). Marine Sciences
2. Geological Survey, Menlo Park, CA (United States)

Rapid episodic accumulation of organic-rich sediment in Cape Lookout Bight, N.C. produces year round anoxic conditions within mm of the sediment-water interface. Approximately 70% of the organic carbon and nitrogen depositional flux is buried beneath zones of rapid sulfate reducing and methane producing sediments. The 30% fraction undergoing bacterial degradation resembles Redfield organic matter whereas the buried fraction consists largely of 400 to greater than 1,000 year old materials resembling degraded algae-bacteria. Seasonality in degradation rates correlates with temperature variation rather than deposition rates as determined by [sup 7]Be inventory. Source specific lipid constituents exhibit seasonality in abundance and in microbially-mediated transformation processes. Remineralization rates are low in winter when accumulation rates are highest and high during summer months when lowest rates of accumulation occur. Degradation rates for specific lipid constituents decrease rapidly beneath the upper half cm of sediment. During summer months a large percentage of previously deposited organic matter is transformed into bacterial material. Bacterial fatty acids thus generated are efficiently remineralized within a few years.

• OSTI ID: 6000311
• Report Number(s): CONF-921058--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 24:7
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
BIODEGRADATION
CHEMICAL REACTIONS
CHEMISTRY
COASTAL WATERS
DECOMPOSITION
DEVELOPED COUNTRIES
DIAGENESIS
GEOCHEMISTRY
GEOLOGIC STRUCTURES
MATTER
NORTH AMERICA
NORTH CAROLINA
ORGANIC MATTER
SEASONAL VARIATIONS
SEDIMENTARY BASINS
SEDIMENTATION
SEDIMENTS
SURFACE WATERS
USA
VARIATIONS