Tracing submarine groundwater discharge in the NE Gulf of Mexico by [sup 222]Rn
- Florida State Univ., Tallahassee, FL (United States). Dept. of Oceanography
Inputs of freshwater and dissolved components to the ocean by submarine groundwater discharge (SGD) have been largely neglected as source functions for biogeochemical budgets. In order to locate and quantify groundwater inputs, a tracing technique has been developed using [sup 222]Rn, a member of the natural [sup 238]U decay-series. Because [sup 222]Rn has a short half-life (t 1/2 = 3.84 days), is an inert gas, is relatively easy to measure at low concentrations, and has concentrations in groundwater several orders of magnitude greater than seawater, it should make an excellent tracer. Excess [sup 222]Rn concentrations far above normal'' ocean values were found in the bottom waters of the northeastern Gulf of Mexico, which suggests this region has significant groundwater discharge. After measuring high water column inventories of excess [sup 222]Rn in this region, an advection/diffusion model was applied to evaluate potential benthic sources of radon. The model is designed to account for sediment diffusion of radon and includes a groundwater term for advective flow into the overlying water. Flow rates and concentrations are adjusted in the model to balance the large difference in the measured water column inventories and the inventory predicted by sediment diffusion alone. The vertical diffusive/advective transport determines the shape of the concentration gradient and fluxes at the sediment-water interface are calculate based on these terms. The authors work shows that SGD could account for as much as 95% of the radon inventory in these offshore waters.
- OSTI ID:
- 6076933
- Report Number(s):
- CONF-9304188--
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Journal Name: Geological Society of America, Abstracts with Programs; (United States) Vol. 25:4; ISSN GAAPBC; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
540211 -- Environment
Terrestrial-- Basic Studies-- Radiometric Techniques-- (1990-)
540311 -- Environment
Aquatic-- Basic Studies-- Radiometric Techniques-- (1990-)
58 GEOSCIENCES
580000* -- Geosciences
ALPHA DECAY RADIOISOTOPES
ATLANTIC OCEAN
CARIBBEAN SEA
CHEMISTRY
DAYS LIVING RADIOISOTOPES
ECOLOGICAL CONCENTRATION
EVEN-EVEN NUCLEI
FLOW MODELS
GROUND WATER
GULF OF MEXICO
HEAVY NUCLEI
HYDROGEN COMPOUNDS
ISOTOPES
MATHEMATICAL MODELS
NUCLEI
OXYGEN COMPOUNDS
RADIOECOLOGICAL CONCENTRATION
RADIOISOTOPES
RADON 222
RADON ISOTOPES
SEAS
SURFACE WATERS
WATER
WATER CHEMISTRY
WATER INFLUX