Title

Radium mass balance and submarine groundwater discharge in Sepetiba Bay, Rio de Janeiro State, Brazil.

SelectedWorks Author Profiles:

Joseph M. Smoak

Document Type

Article

Publication Date

2012

Date Issued

January 2012

Date Available

November 2013

ISSN

0895-9811

Abstract

Radium-226 and Ra-228 activities were determined in water samples from within and adjacent to Sepetiba Bay, Rio de Janeiro State (Brazil) in 1998, 2005 and 2007. Surface waters in Sepetiba Bay were substantially higher in Ra-228 and Ra-228 compared to ocean end member samples. Using the residence time of water in the bay we calculated the flux required to maintain the observed enrichment over the ocean end members. We then applied a radium mass balance to estimate the volume of submarine groundwater discharge (SGD) into the bay. The estimates of SGD into Sepetiba Bay (in 10(10) L day(-1)) were 2.56, 3.75, and 1.0, respectively for 1998, 2005, and 2007. These estimates are equivalent to approximately 1% of the total volume of the bay each day or 50 L m(-2) day(-1). It is likely that a substantial portion of the SGD in Sepetiba Bay consists of infiltrated seawater. This large flux of SGD has the potential to supply substantial quantities of nutrients, carbon and metals into coastal waters. The SGD found here is greater than what is typically found in SGD studies along the eastern United States and areas with similar geologic characteristics. Considering there are many coastal areas around the world like Sepetiba Bay, this could revise upward the already important contribution of SGD to coastal as well as oceanic budgets. (C) 2012 Elsevier Ltd. All rights reserved.

Comments

Abstract only. Full-text article is available only through licensed access provided by the publisher. Published in Journal of South American Earth Sciences, 39, 44-51. DOI: 10.1016/j.jsames.2012.07.004 Members of the USF System may access the full-text of the article through the authenticated link provided.

Language

en_US

Publisher

Elsevier

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.