Influences of Bioavailability, Trophic Position, and Growth on Methylmercury in Hakes (Merluccius merluccius) from Northwestern Mediterranean and Northeastern Atlantic

详细信息    查看全文

• 作者：D. Cossa ; M. Harmelin-Vivien ; C. Mellon-Duval ; V. Loizeau ; B. Averty ; S. Crochet ; L. Chou ; J.-F. Cadiou
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2012
• 出版时间：May 1, 2012
• 年：2012
• 卷：46
• 期：9
• 页码：4885-4893
• 全文大小：461K
• 年卷期：v.46,no.9(May 1, 2012)
• ISSN：1520-5851

文摘

Methylmercury (MeHg) determinations in hake, its food-chain, and the surrounding waters and sediments allowed us to show that the higher length or age normalized mercury concentrations of Northwestern Mediterranean (Gulf of Lions: GoL) muscle hakes compared to its Northeastern Atlantic (Bay of Biscay: BoB) counterpart are due to both biotic and abiotic differences between their ecosystems. Bioenergetic modeling reveals that the slower growth rate of Mediterranean hake favors the MeHg bioaccumulation in the fish muscle and explains most of the difference between GOL and BoB hake populations. In addition, the waters of the Mediterranean hake habitat favor a higher MeHg exposition, due to the upper position of the thermohalocline, where MeHg is formed. Furthermore, we show that, within the Mediterranean hake population, a major increase in the biomagnification power (the slope of the relationships between logMeHg and 未¹⁵N), from 0.36 up to 1.12, occurs when individuals enter adulthood, resulting from the combined effects of lowering growth rate and change in feeding habits. Finally, 未¹⁵N normalized Hg concentrations indicate that the highest Hg concentrations are for hake from the shelf edge and the lowest are for hake from the Rh么ne prodelta area, suggesting a lower Hg bioavailability in inshore environments, consistent with MeHg distributions in water, sediment, and preys.