Biogeochemical cycling in an organic-rich coastal marine basin. 5. Sedimentary nitrogen and phosphorus budgets based upon kinetic models, mass balances, and the stoichiometry of nutrient regeneration
The rapid rates of sediment accumulation (approx.10-20 cm/yr) in the recently formed Cape Lookout Bight, North Carolina, have resulted in the deposition of approximately 157 moles of carbon, 14 moles of nitrogen and 1.3 moles of phosphorus, per square meter annually. The metabolism of the organic matter in these anoxic sediments is dominated by sulfate reduction and fermentation reactions. Sedimentary nitrogen and phosphorus budgets are estimated using 3 related approaches: 1) a kinetic model of solid phase diagenesis; 2) direct measurements of nutrient burial and regeneration; and 3) nutrient recycling rates estimated from annual rates of sulfate reduction and the SO/sub 4/:NH/sub 4/ and SO/sub 4/:PO/sub 4/ stoichiometry of nutrient regeneration. The mass balances derived agree reasonably well and indicate that approximately 30% of the total nitrogen and 15% of the total phosphorus deposited in these sediments are recycled. The mean residence time for recycled nutrients within the sediment is 4 to 6 months for nitrogen and 1.5 to 2 years for phosphorus. Nitrogen regeneration, like carbon, appears to be controlled by the microbially-mediated metabolism of labile organic matter. The greater asymmetry and lower percent turnover in phosphorus cycling is apparently due to changes in its solubility under oxidized and reduced conditions and selective regeneration prior to deposition.
- Research Organization:
- Univ. of Wisconsin, Milwaukee (USA)
- OSTI ID:
- 7160115
- Journal Information:
- Geochim. Cosmochim. Acta; (United States), Vol. 51:5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
CONTINENTAL SHELF
SEDIMENTS
BIOGEOCHEMISTRY
DIAGENESIS
MINERAL CYCLING
ORGANIC MATTER
CARBON
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
FERMENTATION
MASS BALANCE
METABOLIC ACTIVATION
METABOLISM
NITROGEN
NITROGEN CYCLE
NORTH CAROLINA
PHOSPHORUS
REDUCTION
SEDIMENTARY BASINS
SEDIMENTATION
STOICHIOMETRY
SULFATES
BIOCONVERSION
CHEMISTRY
CONTINENTAL MARGIN
ELEMENTS
FEDERAL REGION IV
GEOCHEMISTRY
GEOLOGIC STRUCTURES
KINETICS
NONMETALS
NORTH AMERICA
OXYGEN COMPOUNDS
REACTION KINETICS
SULFUR COMPOUNDS
USA
580400* - Geochemistry- (-1989)
550200 - Biochemistry