Geochemistry of dissolved gases in the hypersaline Orca basin. Technical report

Technical Report · Mon Dec 01 00:00:00 EST 1980

OSTI ID:5782403

Wiesenburg, D A

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

Related Subjects

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SEDIMENTARY BASINS
ANAEROBIC CONDITIONS
ANAEROBIC DIGESTION
ANOXIA
BRINES
DIFFUSION
DISTRIBUTION
GAS ANALYSIS
GASES
GEOCHEMISTRY
GEOTHERMAL HEATING
GULF OF MEXICO
MOLECULES
OCEANOGRAPHY
REACTION KINETICS
SALINITY
THERMAL DIFFUSION
WATER CHEMISTRY
ATLANTIC OCEAN
BIOCONVERSION
CARIBBEAN SEA
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DIGESTION
ENERGY SOURCES
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GEOLOGIC STRUCTURES
HEATING
KINETICS
MANAGEMENT
PROCESSING
SEAS
SURFACE WATERS
WASTE MANAGEMENT
WASTE PROCESSING
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