Coastal Loading and Transport of<i>Escherichia coli</i>at an Embayed Beach in Lake Michigan

Ge, Zhongfu; Nevers, Meredith B.; Schwab, David J.; Whitman, Richard L.

doi:10.1021/es100797r

Cited by 52 publications

(65 citation statements)

References 27 publications

(37 reference statements)

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“…In addition to marine water bodies, the POM has been successfully applied to the entire Lake Michigan (Beletsky and Schwab 2001) as well as considerably smaller areas, such as coastal waters in southern Lake Michigan (Thupaki et al 2010). In contrast to open coastal waters (Thupaki et al 2010), the embayed 63rd Street Beach has interesting flow structures, such as flow separation, recirculation (gyres) due to the blockage effect of the breakwaters, and the formation of turbulent shear layer near the opening of the embayment (Ge et al 2010).…”

Section: Methodsmentioning

confidence: 99%

Nearshore hydrodynamics as loading and forcing factors for Escherichia coli contamination at an embayed beach

Whitman

Nevers

et al. 2012

Limnology & Oceanography

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Numerical simulations of the transport and fate of Escherichia coli were conducted at Chicago's 63rd Street Beach, an embayed beach that had the highest mean E. coli concentration among 23 similar Lake Michigan beaches during summer months of [2000][2001][2002][2003][2004][2005], in order to find the cause for the high bacterial contamination. The numerical model was based on the transport of E. coli by current circulation patterns in the embayment driven by longshore main currents and the loss of E. coli in the water column, taking settling as well as bacterial dark-and solar-related decay into account. Two E. coli loading scenarios were considered: one from the open boundary north of the embayment and the other from the shallow water near the beachfront. Simulations showed that the embayed beach behaves as a sink for E. coli in that it generally receives E. coli more efficiently than it releases them. This is a result of the significantly different hydrodynamic forcing factors between the inside of the embayment and the main coastal flow outside. The settled E. coli inside the embayment can be a potential source of contamination during subsequent sediment resuspension events, suggesting that deposition-resuspension cycles of E. coli have resulted in excessive bacterial contamination of beach water. A further hypothetical case with a breakwater shortened to half its original length, which was anticipated to enhance the current circulation in the embayment, showed a reduction in E. coli concentrations of nearly 20%.Beach water, as the interface between the land and coastal waters, is a dynamic physical and ecological system. The transport and fate of fecal indicator bacteria (FIB) in beach water not only have direct implications for human health in coastal areas (Nevers and Whitman 2005;Frick et al. 2008) but also constitute an integral influence on the coastal ecosystem. Recently, computational models allowing for a simulation of temporal and spatial variations of model variables have been developed to understand microbial water quality in open beach waters of Lake Michigan (Liu et al. 2006;Thupaki et al. 2010). Embayed (i.e., partially enclosed) beach waters have been of particular interest because of their significantly more complex hydrodynamic properties and the tendency to accumulate FIB and other contaminants (Grant and Sanders 2010).The 63rd Street Beach of Chicago, a frequently closed beach, had by far the highest Escherichia coli concentration (geometric mean 140 MPN [most probable number], 100 mL 21 ) among 23 recreational beaches along Chicago's 37-km Lake Michigan shoreline during 2000-2005. In comparison, the site with the second-highest E. coli concentration was Montrose Beach, with a geometric mean of only 77 MPN 100 mL 21 (Whitman and Nevers 2008). Since typical meteorological (e.g., rainfall) and hydrodynamic (e.g., current and wave) events usually have spatial scales larger than 37 km, the unique situation of microbial contamination at 63rd Street Beach likely resulted from local facto...

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Section: Methodsmentioning

confidence: 99%

Nearshore hydrodynamics as loading and forcing factors for Escherichia coli contamination at an embayed beach

Whitman

Nevers

et al. 2012

Limnology & Oceanography

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“…Numerous studies have shown that beach sand may serve as a reservoir for pathogens harmful to human health and indicator microbes that can be released into surrounding waters through tidal action or run-off (Alm et al, 2003;Whitman and Nevers, 2003;Boehm and Weisberg, 2005;Beversdorf et al, 2007;Colford et al, 2007;Fleisher et al, 2010;Ge et al, 2010;Sinigalliano et al, 2010;Abdelzaher et al, 2010). Several authors have reported that both indicator bacteria and potential pathogens occur in beach sands of both freshwater and marine environments (Sanchez et al, 1986;Ghinsberg et al, 1994Ghinsberg et al, , 1995Obiri-Danso and Jones, 2000;Desmarais et al, 2002;Sato et al, 2005;Vantarakis et al, 2005;Beversdorf et al, 2007;Bonilla et al, 2007;Vogel et al, 2007;Hartz et al, 2008;Abdelzaher et al, 2010).…”

Section: Bacteriamentioning

confidence: 99%

Routine screening of harmful microorganisms in beach sands: Implications to public health

Sabino

Rodrigues

Costa

et al. 2014

Science of The Total Environment

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Beaches worldwide provide recreational opportunities to hundreds of millions of people and serve as important components of coastal economies. Beach water is often monitored for microbiological quality to detect the presence of indicators of human sewage contamination so as to prevent public health outbreaks associated with water contact. However, growing evidence suggests that beach sand can harbor microbes harmful to human health, often in concentrations greater than the beach water. Currently, there are no standards for monitoring, sampling, analyzing, or managing beach sand quality. In addition to indicator microbes, growing evidence has identified pathogenic bacteria, viruses, and fungi in a variety of beach sands worldwide. The public health threat associated with these populations through direct and indirect contact is unknown because so little research has been conducted relating to health outcomes associated with sand quality. In this manuscript, we present the consensus findings of a workshop of experts convened in Lisbon, Portugal to discuss the current state of knowledge on beach sand microbiological quality and to develop suggestions for standardizing the evaluation of sand at coastal beaches. The expert group at the "Microareias 2012" workshop recommends that 1) beach sand should be screened for a variety of pathogens harmful to human health, and sand monitoring should then be initiated alongside regular water monitoring; 2) sampling and analysis protocols should be standardized to allow proper comparisons among beach locations; and 3) further studies are needed to estimate human health risk with exposure to contaminated beach sand. Much of the manuscript is focused on research specific to Portugal, but similar results have been found elsewhere, and the findings have worldwide implications.

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“…However, contamination of beach sands by pollution in the water has also been suggested (9). Bacteria in beach sands may also enter the water column via overbeach transport, where tidal events or wave action release bacteria attached to sand particles or those residing in interstitial spaces and these bacteria then enter the water directly (10,11). Alternatively, throughbeach transport can also occur when bacteria in unsaturated sands are mobilized downward due to tidal or wave action, enter the groundwater, and are transported via subterranean discharge to the water column (3,12).…”

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confidence: 99%

Regional Similarities and Consistent Patterns of Local Variation in Beach Sand Bacterial Communities throughout the Northern Hemisphere

Staley

Sadowsky

2016

Appl Environ Microbiol

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Recent characterization of the bacterial community structure in beach sands has revealed patterns of biogeography similar to those observed in aquatic environments. Studies to date, however, have mainly focused on subtidal sediments from marine beaches. Here, we investigate the bacterial diversity, using Illumina-based sequencing of the V5-V6 region of the 16S rRNA gene, at 11 beaches representing those next to the Great Lakes, Florida, and the Pacific Ocean. The alpha diversity differed significantly among regions (P < 0.0001), while the within-region diversity was more similar. The beta diversity also differed by region (P < 0.001), where freshwater sands had significantly higher abundances of taxa within the Actinobacteria, Betaproteobacteria, and Verrucomicrobia than marine environments. In contrast, marine sands harbored greater abundances of Gammaproteobacteria and Planctomycetes, and those from Florida had more Deltaproteobacteria and Firmicutes. Marine beaches had significantly different phylogenetic community structures (P < 0.018), but freshwater and Florida beaches showed fewer within-region phylogenetic differences. Furthermore, regionally distinct patterns in taxonomic variation were observed in backshore sands, which had communities distinct from those in nearshore sands (P < 0.001). Sample depth minimally influenced the community composition. The results of this study reveal distinct bacterial community structures in sand on a broad geographic scale but moderate regional similarity and suggest that local variation is primarily related to the distance from the shoreline. This study offers a novel comparison of the bacterial communities in freshwater and marine beach sands and provides an important basis for future comparisons and analyses to elucidate factors affecting microbial ecology in this underexplored environment. IMPORTANCEThis study presents a large-scale geographic characterization of the bacterial communities present in beach sands. While previous studies have evaluated how environmental factors influence bacterial community composition, few have evaluated bacterial communities in freshwater sands. Furthermore, the use of a consistent methodology to characterize bacterial communities here allowed a novel comparison of communities across geographic regions. We reveal that while the community composition in sands at individual beaches is distinct, beach sands within the same region harbor similar assemblages of bacteria and these assemblages differ greatly between regions. In addition, moisture, associated with distance from the shoreline, strongly influences the bacteria present in sands and more strongly influences the bacteria present than sample depth does. Thus, the data presented here offer an important basis for a broader characterization of the ecology of bacteria in sands, which may also be relevant to public health and resource management initiatives.

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Coastal Loading and Transport ofEscherichia coliat an Embayed Beach in Lake Michigan

Cited by 52 publications

References 27 publications

Nearshore hydrodynamics as loading and forcing factors for Escherichia coli contamination at an embayed beach

Nearshore hydrodynamics as loading and forcing factors for Escherichia coli contamination at an embayed beach

Routine screening of harmful microorganisms in beach sands: Implications to public health

Regional Similarities and Consistent Patterns of Local Variation in Beach Sand Bacterial Communities throughout the Northern Hemisphere

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