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Title: Tracing submarine groundwater discharge in the NE Gulf of Mexico by [sup 222]Rn

Abstract

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 transportmore » 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.« less

Authors:
; ; ; ;  [1]
  1. Florida State Univ., Tallahassee, FL (United States). Dept. of Oceanography
Publication Date:
OSTI Identifier:
6076933
Report Number(s):
CONF-9304188-
Journal ID: ISSN 0016-7592; CODEN: GAAPBC
Resource Type:
Conference
Journal Name:
Geological Society of America, Abstracts with Programs; (United States)
Additional Journal Information:
Journal Volume: 25:4; Conference: 42. annual Geological Society of America (GSA) Southeastern Section meeting, Tallahassee, FL (United States), 1-2 Apr 1993; Journal ID: ISSN 0016-7592
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 54 ENVIRONMENTAL SCIENCES; GROUND WATER; WATER INFLUX; GULF OF MEXICO; WATER CHEMISTRY; FLOW MODELS; RADIOECOLOGICAL CONCENTRATION; RADON 222; ALPHA DECAY RADIOISOTOPES; ATLANTIC OCEAN; CARIBBEAN SEA; CHEMISTRY; DAYS LIVING RADIOISOTOPES; ECOLOGICAL CONCENTRATION; EVEN-EVEN NUCLEI; HEAVY NUCLEI; HYDROGEN COMPOUNDS; ISOTOPES; MATHEMATICAL MODELS; NUCLEI; OXYGEN COMPOUNDS; RADIOISOTOPES; RADON ISOTOPES; SEAS; SURFACE WATERS; WATER; 580000* - Geosciences; 540211 - Environment, Terrestrial- Basic Studies- Radiometric Techniques- (1990-); 540311 - Environment, Aquatic- Basic Studies- Radiometric Techniques- (1990-)

Citation Formats

Young, J E, Burnett, W C, Chanton, J P, Cable, P H, and Corbett, D R. Tracing submarine groundwater discharge in the NE Gulf of Mexico by [sup 222]Rn. United States: N. p., 1993. Web.
Young, J E, Burnett, W C, Chanton, J P, Cable, P H, & Corbett, D R. Tracing submarine groundwater discharge in the NE Gulf of Mexico by [sup 222]Rn. United States.
Young, J E, Burnett, W C, Chanton, J P, Cable, P H, and Corbett, D R. Mon . "Tracing submarine groundwater discharge in the NE Gulf of Mexico by [sup 222]Rn". United States.
@article{osti_6076933,
title = {Tracing submarine groundwater discharge in the NE Gulf of Mexico by [sup 222]Rn},
author = {Young, J E and Burnett, W C and Chanton, J P and Cable, P H and Corbett, D R},
abstractNote = {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.},
doi = {},
journal = {Geological Society of America, Abstracts with Programs; (United States)},
issn = {0016-7592},
number = ,
volume = 25:4,
place = {United States},
year = {1993},
month = {3}
}

Conference:
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