Temporal variability of water quality of submarine groundwater discharge in Ubatuba, Brazil

Taniguchi, M., Stieglitz, T., and Ishitobi, T. (2008) Temporal variability of water quality of submarine groundwater discharge in Ubatuba, Brazil. Estuarine, Coastal and Shelf Science , 76 (3). pp. 484-492.

[img] PDF (Published Version)
Restricted to Repository staff only

View at Publisher Website: http://dx.doi.org/10.1016/j.ecss.2007.07...

Abstract

Measurements of electric resistivity of the seabed and of the electric conductivity of submarine groundwater discharge (SGD) collected in seepage meters have been made to evaluate temporal variability of the origin and quality of submarine groundwater discharge in Ubatuba, Brazil. A diurnal variation of SGD conductivity was found under the condition of semi-diurnal tidal changes over a period of 4 days. Both the ground resistivity and the conductivity of the discharged groundwater indicated that the freshwater–saltwater interface moved towards offshore at high tide, i.e. in the direction opposite to commonly made observations. SGD comprised a combination of Submarine Fresh Groundwater Discharge (SFGD) of terrestrial origin, and of Recirculated Saline Groundwater Discharge (RSGD) of marine origin. The maximum of the terrestrially derived fraction SFGD/SGD was found at a distance of 50 m offshore. A lower SFGD/SGD ratio was found closer to shore, where the highest SGD flux was measured. SGD conductivity and ground resistivity displayed a diurnal cyclicity at semi-diurnal tidal water level variations, indicating that tidal water level fluctuations may not be the primary driver of SGD flux, but preferential flow in volcanic hydrogeologic setting at Ubatuba.

Item ID: 6294
Item Type: Article (Refereed Research - C1)
Keywords: submarine groundwater discharge; resistivity; saltwater-freshwater interface; temporal variability; Ubatuba; Brazil
ISSN: 1096-0015
Date Deposited: 21 Jan 2010 06:22
FoR Codes: 04 EARTH SCIENCES > 0405 Oceanography > 040503 Physical Oceanography @ 100%
SEO Codes: 96 ENVIRONMENT > 9611 Physical and Chemical Conditions of Water > 961103 Physical and Chemical Conditions of Water in Fresh, Ground and Surface Water Environments (excl. Urban and @ 100%
Citation Count from Web of Science Web of Science 15
Downloads: Total: 1
More Statistics

Actions (Repository Staff Only)

Item Control Page Item Control Page