Geochemistry of dissolved gases in the hypersaline Orca basin. Technical report
Hypersaline, anoxic waters significantly affect the biogeochemistry of dissolved gases in the Orca Basin (Northern Gulf of Mexico). The high stability of the Orca brine pool makes it an ideal laboratory for studying production and consumption of dissolved gases during anaerobic decomposition. Depth distributions were determined for nitrogen, oxygen, argon, methane, ethane, propane, ammonia, hydrogen sulfide, and nitrous oxide. Physical stratification of the water column strongly influences Orca Basin gas distributions. The high salinity brine (approx. 250%) is internally well mixed due to convective overturning, but transfer across the brine-sea water interface is controlled by molecular diffusion. With a molecular diffusivity of 0.00001 sq cm/sec, it will take 1,000,000 years for all salts to diffuse from the basin. Heat diffuses faster than salt and is lost from the basin at a rate of 0.5 microcal sq cm/sec. If geothermal heat input from the sediments is slightly higher, this input could account for the higher temperature in the brine (5.6C) compared to the deep Gulf waters (4.2 C). This study has shown the utility of dissolved gases in examining water chemistry of unusual areas. Since sources of dissolved gases are independent of the sources of major ions in solution, calculations of gas distributions on a salt-free basis are useful in examining production and consumption processes.
- Research Organization:
- Texas A and M Univ., College Station (USA). Dept. of Oceanography
- OSTI ID:
- 5782403
- Report Number(s):
- AD-A-103536/9
- Country of Publication:
- United States
- Language:
- English
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ANAEROBIC CONDITIONS
ANAEROBIC DIGESTION
ANOXIA
ATLANTIC OCEAN
BIOCONVERSION
BRINES
CARIBBEAN SEA
CHEMISTRY
DIFFUSION
DIGESTION
DISTRIBUTION
ENERGY SOURCES
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS ANALYSIS
GAS FUELS
GASES
GEOCHEMISTRY
GEOLOGIC STRUCTURES
GEOTHERMAL HEATING
GULF OF MEXICO
HEATING
KINETICS
MANAGEMENT
MOLECULES
NATURAL GAS
OCEANOGRAPHY
PROCESSING
REACTION KINETICS
SALINITY
SEAS
SEDIMENTARY BASINS
SURFACE WATERS
SYNTHESIS
THERMAL DIFFUSION
WASTE MANAGEMENT
WASTE PROCESSING
WATER CHEMISTRY