Temporal variations in fecal indicator bacteria in bathing water and sediment in a coastal ecosystem (Aytré Bay, Charente-Maritime, France) - Archive ouverte HAL Access content directly
Journal Articles Marine Pollution Bulletin Year : 2022

Temporal variations in fecal indicator bacteria in bathing water and sediment in a coastal ecosystem (Aytré Bay, Charente-Maritime, France)

Abstract

Coastal ecosystems are popular environments for economic and recreational activities that may be exposed to fecal contamination. We present a one-year survey of the fecal indicator bacteria dynamics in the bathing water and beach sediment of Aytré Bay (Charente Maritime, France). First, we quantified the Escherichia coli and intestinal enterococci abundance, representing fecal indicator contamination, according to Bathing Water Directive (BWD, European Union 2006/7/CE). Then, we measured the total bacterial abundance and the environmental characteristics of the beach, which included chemical (ammonia, nitrate, nitrite, silicate, phosphate, salinity, pH, dissolved oxygen, and total organic carbon) and climatic (rainfall, temperature at water and sediment surface, air temperature and tidal coefficient) parameters. By sampling the water and the sediment at two sites in the beach, we showed that the fecal indicator bacteria (FIB) were occasionally higher than the regulatory threshold during winter, summer and fall. The “poor quality” of the bathing water at the two sampling sites was mainly due to high intestinal enterococci abundance. The FIB abundances were globally correlated between the two sampling sites and between the water and sediment samples in the North Platin site. We found negative significant correlations between FIB and water temperature and salinity, and positive significant correlations between FIB and rainfall, PO4, NO3, NO2 and SiO2 mainly in the water samples. The relationships between all parameters showed that the main environmental drivers in the water and sediment samples during summer and spring were water temperature and salinity, while in fall and winter; the main environmental drivers were rainfall and dissolved nutrients. These results suggested that FIB occurrence at the two bathing sites of the Aytré Bay had different temporal dynamics according to the seasons.
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Dates and versions

hal-03602378 , version 1 (13-02-2024)

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Méry Ndione, Pascaline Ory, Tony Agion, Michaël Treilles, Luc Vacher, et al.. Temporal variations in fecal indicator bacteria in bathing water and sediment in a coastal ecosystem (Aytré Bay, Charente-Maritime, France). Marine Pollution Bulletin, 2022, 175, pp.113360. ⟨10.1016/j.marpolbul.2022.113360⟩. ⟨hal-03602378⟩
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