Mercury in the open mediterranean: Evidence of contamination?

Aston, S.R.; Fowler, Scott W.

doi:10.1016/0048-9697(85)90028-2

Cited by 49 publications

(23 citation statements)

References 13 publications

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“…Finally, from an ecological point of view, our finding that net Hg methylation in the open ocean is promoted by the presence of nano-and picophytoplankton, that dominate under oligotrophic conditions, is consistent with the hyperbioaccumulation of methyl mercury in the Mediterranean top predatory animals discovered more than 25 years ago (see review by Aston and Fowler, 1985). It can be reasonably speculated that high methylmercury biomagnification in oligotrophic Mediterranean food webs is favored by higher methylmercury incorporation by the microbial food web (Kainz and Mazumder, 2005), and higher bioamplification due to the longer food web (Cabana and Rasmussen, 1994), compared to ecosystems based on microphytoplankton.…”

Section: Discussionsupporting

confidence: 83%

Methyl mercury distributions in relation to the presence of nano- and picophytoplankton in an oceanic water column (Ligurian Sea, North-western Mediterranean)

Heimbürger

Cossa

Marty

et al. 2010

Geochimica et Cosmochimica Acta

161

155

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Recent findings on the distribution of methylated mercury (MeHg T ) in waters have highlighted the importance of organic carbon remineralization on the production of these compounds in the open ocean. Here, we present the first time-series (20 monthly samplings between July 2007 and May 2009) of high-resolution vertical profiles (10-12 depths in a 2350 m water column) of MeHg T distributions in an open ocean environment, the Ligurian Sea (North-western Mediterranean Sea). Concentrations varied within the sub-picomolar range (general mean: 0.30 ± 0.17 pmol L À1 , n = 214) with the lowest values at the surface, increasing with depth up to the oxygen minimum zone, and decreasing slowly at greater depth. Concentrations in the surface waters never exceeded 0.15 pmol L À1 , while the highest concentrations (up to 0.82 pmol L À1 ) were associated to the hypoxycline during the autumn bloom. A detailed vertical MeHg T profile reveals a "double-peak" pattern, coincidental with the two microbial layers described by Tanaka and Rassoulzadegan (2002), the so-called "microbial food web" in the euphotic zone (<100 m) and the "microbial loop" in the aphotic zone (>100 m). Temporal variations in the MeHg T abundance and distribution in the water column were linked to seasonality. The highest MeHg T concentrations were found in the oxygen minimum zone during the period of stratification, and coincide with the greatest abundance of nano-and picophytoplankton (cyanobacteria, nanoflagellates, etc.) in the euphotic layer. None of our deep MeHg T measurements ($100 m above the sea bottom) revealed a significant sedimentary source of MeHg T . We explored the correlation between MeHg T concentrations and the apparent oxygen utilization, a proxy of organic matter remineralization, over the study period. Results of this study strengthen the hypothesis that net mercury methylation in the open ocean occurs in the water column, is linked to organic matter regeneration, and is promoted by the presence of small-sized nano-and picophytoplankton, that dominate under oligotrophic conditions.

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Section: Discussionsupporting

confidence: 83%

Methyl mercury distributions in relation to the presence of nano- and picophytoplankton in an oceanic water column (Ligurian Sea, North-western Mediterranean)

Heimbürger

Cossa

Marty

et al. 2010

Geochimica et Cosmochimica Acta

161

155

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“…These findings partly answer to the "mercury enigma" in Mediterranean waters pointed out thirty years ago (Aston and Fowler, 1985). However, the study of MeHg uptake by phytoplankton and its transfer through the various components of trophic webs is a challenging issue for better understanding its bioaccumulation and biomagnification processes in marine fishes.…”

Section: Risk Consequencesmentioning

confidence: 71%

“…Aston and Fowler (1985) reviewed the main hypotheses that may explain these observations, from the bioavailability of mercury in waters to the specificities of the Mediterranean food web structures. However, they failed to reach a clear conclusion and suggested that more data were needed to resolve these issues.…”

Section: Introductionmentioning

confidence: 99%

Difference of mercury bioaccumulation in red mullets from the north-western Mediterranean and Black seas

Harmelin-Vivien

Cossa

Crochet

et al. 2009

Marine Pollution Bulletin

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Abstract:The relationships between total mercury (Hg) concentration and stable nitrogen isotope ratio (δ 15 N) were evaluated in Mullus barbatus barbatus and M. surmuletus from the Mediterranean Sea and M. barbatus ponticus from the Black Sea. Mercury concentration in fish muscle was six times higher in the two Mediterranean species than in the Black Sea one for similar sized animals. A positive correlation between Hg concentration and δ 15 N occurred in all species. Increase in Hg concentration with δ 15 N was high and similar in the two Mediterranean fishes and much lower in the Black Sea species. Since this was neither related to trophic level difference between species nor to methylmercury (MeHg) concentration differences between the north-western Mediterranean and the Black Sea waters, we suggested that the higher primary production of the Black Sea induced a dilution of MeHg concentration at the base of the food webs.

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“…higher Hg concentrations in Mediterranean individuals when compared with other oceans, even if concentrations in water or sediment were not significantly different (Aston and Fowler, 1985;Cossa and Coquery, 2005). Oligotrophy of the Mediterranean Sea was one of the main explanations of this discrepancy, as it drives the biogeochemical Hg cycle, the life history traits and the contamination pattern of the species (Cossa and Coquery, 2005;Harmelin-Vivien et al, 2009;Heimbürger et al, 2010;Cossa et al, 2012).…”

Section: The "Corsican Mercury Anomaly" An Effect Of Oligotrophy?mentioning

confidence: 90%

“…The case of Hg is peculiar in the Mediterranean, as biogeochemical and biological features of this sea cause the "Mediterranean mercury anomaly", i.e. higher Hg concentrations in Mediterranean organisms than in conspecifics from other environments, whereas Hg concentrations in water or sediment do not differ (Aston and Fowler, 1985;Cossa and Coquery, 2005;Cossa et al, 2009Cossa et al, , 2012Harmelin-Vivien et al, 2009;Heimbürger et al, 2010). Polychlorinated biphenyls (PCBs) are a group of synthetic organochlorinated compounds which have been produced as commercial technical mixtures since the 1920s.…”

Section: Introductionmentioning

confidence: 99%

A multitracer approach to assess the spatial contamination pattern of hake (Merluccius merluccius) in the French Mediterranean

Cresson

Bouchoucha

Morat³

et al. 2015

Science of The Total Environment

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Chemical contamination levels and stable isotope ratios provide integrated information about contaminant exposure, trophic position and also biological and environmental influences on marine organisms. By combining these approaches with otolith shape analyses, the aim of the present study was to document the spatial variability of Hg and PCB contamination of the European hake (Merluccius merluccius) in the French Mediterranean, hypothesizing that local contaminant sources, environmental conditions and biological specificities lead to site-specific contamination patterns. High Hg concentrations discriminated Corsica (average: 1.36 ± 0.80 μg g(-1) dm) from the Gulf of Lions (average values<0.5 μg g(-1) dm), where Rhône River input caused high PCB burdens. CB 153 average concentrations ranged between 4.00 ± 0.64 and 18.39 ± 12.38 ng g(-1) dm in the Gulf of Lions, whatever the sex of the individuals, whereas the highest values in Corsica were 6.75 ± 4.22 ng g(-1) dm. Otolith shape discriminated juveniles and adults, due to their different habitats. The use of combined ecotracers was revealed as a powerful tool to discriminate between fish populations at large and small spatial scale, and to enable understanding of the environmental and biological influences on contamination patterns.

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Mercury in the open mediterranean: Evidence of contamination?

Cited by 49 publications

References 13 publications

Methyl mercury distributions in relation to the presence of nano- and picophytoplankton in an oceanic water column (Ligurian Sea, North-western Mediterranean)

Methyl mercury distributions in relation to the presence of nano- and picophytoplankton in an oceanic water column (Ligurian Sea, North-western Mediterranean)

Difference of mercury bioaccumulation in red mullets from the north-western Mediterranean and Black seas

A multitracer approach to assess the spatial contamination pattern of hake (Merluccius merluccius) in the French Mediterranean

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