Fluorescence properties of dissolved organic matter in coastal Mediterranean waters influenced by a municipal sewage effluent (Bay of Marseilles, France)

Abstract

International audienceFluorescent dissolved organic matter (FDOM) in coastal marine waters influenced by the municipal sewage effluent (SE) from Marseilles City (France, north-western Mediterranean Sea) has been characterised. Samples were collected eleven times from September 2008 to June 2010 in the Bay of Marseilles along a coast-open sea transect from the SE outlet in the South Bay and at the Mediterranean Institute Observation site in the central Bay. Fluorescence excitation-emission matrices combined with parallel factor analysis (PARAFAC) allowed the identification of two protein-like (tyrosine C1, with excitation maxima (lEx) and an emission maximum (lEm) of ,230, 275/306 nm; tryptophan C2, lEx/lEm,230, 270/346 nm) and three humic-like components (marine humic C3, lEx/lEm 280/386 nm; C4, lEx/lEm 235, 340/410 nm; C5, lEx/lEm 255, 365/474 nm). From the SE outlet to the central Bay, a gradient appeared, with decreasingFDOM intensities, decreasing dissolved organic carbon, particulate carbon, nutrients and faecal bacteria concentrations and increasing salinity values. This gradient was associated with decreasing abundances in protein-like fluorophores and rising abundances in humic-like (C3 and C5) materials. This shift in FDOM composition illustrated the decrease in wastewater inputs and the increase in marine sources of DOM along the transect. FDOM data showed that the Marseilles SE spread up to 1500m off the outlet, but it did not reach the central Bay. Tryptophan-like material was the dominant fluorophore in the SE and displayed the highest correlations with biogeochemical parameters (organic carbon, phosphates, faecal bacteria). Therefore, it is proposed to use its fluorescence intensity to detect and track SE inputs in the Marseilles coastal marine waters

Evolution of dissolved and particulate chromophoric materials during the VAHINE mesocosm experiment in the New Caledonian coral lagoon (south-west Pacific)

“…They represent compounds of low molecular weight at the state of free amino acids or amino acids bound in peptides or proteins. They are known to be released by autochthonous (marine) phytoplankton activity and serve as fresh and labile bioavailable products for heterotrophic bacteria (Yamashita and Tanoue, 2004;Nieto-Cid et al, 2006;Davis and Benner, 2007;RomeraCastillo et al, 2010;Tedetti et al, 2012). Moreover, they can be directly associated to humic substances (Stedmon and Cory, 2014).…”

“…The full analysis showed that no outliers were present in the data set. The validation of the PARAFAC model (running with the non-negativity constraint) and the determination of the correct number of components (from 2 to 6 components tested) were achieved through the examination of (1) the percentage of explained variance, (2) the shape of residuals, (3) the split half analysis and (4) the random initialization using the Tucker Congruence Coefficients (Tedetti et al, 2012). The fluorescence intensities of each component found are given in QSU.…”

“…The correction of spectra for instrumental response was conducted from 200 to 600 nm according to the procedure recommended by the manufacturer (Hitachi F-7000 Instruction Manual) and fully described in Tedetti et al (2012). The excitation (Ex) and emission (Em) correction curves were applied internally by the instrument to correct each fluorescence measurement acquired in signal over reference ratio mode.…”

Upwelling in the Kerch Strait and the adjacent waters of the Black Sea based on the contact and satellite data

“…Из-за сложности определения содержания этого веще-ства массовые сведения о нем стали возможными относительно недавно. В последние годы этот параметр активно используется для оценки качества вод прибрежных океанских и морских акваторий [15,16].…”

A New Glider-Compatible Optical Sensor for Dissolved Organic Matter Measurements: Test Case from the NW Mediterranean Sea

“…However, Trp is not only associated with wastewater bacterial activities, and is now becoming recognized as a by-product of marine primary production. Recent works suggest a relation between Trp and some phytoplankton groups or bacterial activities (Hudson et al, 2007;Suksomjit et al, 2009;Tedetti et al, 2012;Amin et al, 2015). Trp is also believed to act as a pheromone playing a role in sexual reproduction in marine environment (Riffell et al, 2004;Yambe et al, 2006).…”