Beach nourishment impacts on bacteriological water quality and phytoplankton bloom dynamics

TitleBeach nourishment impacts on bacteriological water quality and phytoplankton bloom dynamics
Publication TypeJournal Article
Year of Publication2013
AuthorsRippy MA, Franks PJS, Feddersen F, Guza RT, Warrick J.A
JournalEnvironmental Science & Technology
Date Published2013/06
Type of ArticleArticle
ISBN Number0013-936X
Accession NumberWOS:000320749000011
Keywordscalifornia; coastal waters; Fecal indicator bacteria; hepatitis-a virus; huntington-beach; marine beach; southern; sunlight inactivation; surf-zone; tijuana-estuary; urban runoff

A beach nourishment with approximately 1/3 fine-grained sediment (fines; particle diameter <63 mu m) by mass was performed at Southern California's Border Fields State Park (BFSP). The nourishment was found to briefly (<1 day) increase concentrations of surf-zone fecal indicator bacteria (FIB) above single-sample public health standards [104 most probable number (MPN).(100 mL)(-1)] but had no effect on phytoplankton. Contamination was constrained to the nourishment site: waters 300 m north or south of the nourishment were always below single-sample and geometric mean [<= 35 MPN.(100 mL)(-1)] standards. Nourishment fines were identified as a source of the fecal indicator Enterococcus; correlations between fines and enterococci were significant (p < 0.01), and generalized linear model analysis identified fines as the single best predictor of enterococci. Microcosm experiments and field sampling suggest that the short surf-zone residence times observed for enterococci (e-folding time 4 h) resulted from both rapid, postplacement FIB inactivation and mixing/transport by waves and alongshore currents. Nourishment fines were phosphate-rich/nitrogen-poor and were not correlated with surf-zone phytoplankton concentrations, which may have been nitrogen-limited.

Short TitleEnviron. Sci. Technol.
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