在河口食物网中,双壳软体动物将营养物质和污染物转移到更高的营养水平。汞(Hg)污染无处不在,但在历史上受工业活动影响的河口,比如美国东北部。单甲基汞(MeHg),汞的有机形式,在食物网中具有高度的生物蓄积性和可转移性,导致最大和最古老的海洋捕食者的浓度最高。海洋双壳软体动物中汞的浓度模式,然而,知之甚少。在这项研究中,无机Hg(iHg),MeHg,以及北部quahogs(Mercenariamercenaria)软组织中的总汞(THg),东部牡蛎(Crassostreavirginica),和来自长岛东部声音的罗纹贻贝(Geukensiademissa),调查了北大西洋西部的一个温带河口。在所有三个物种中,THg的浓度在四个采样月之间保持相似(5月,六月,七月,和9月),并且大多与动物的大小无关。在quahogs,MeHg和iHg显示出显着(p<0.05)正(5月和6月的iHg)和负(7月和9月的MeHg)随壳高的变化而变化。THg浓度的变异性,MeHg,还有iHg,在quahogs和牡蛎中,跨特异性和内特异性都很高,而且更大(THg:37,39%,甲基汞:28,39%,分别)比贻贝(THg:13%,MeHg:20%)。THg是MeHg(%MeHg)的百分比在这三个物种中也是高度可变的(范围:10-80%),强调测量甲基汞的重要性,而不仅仅是软体动物中的THg。
In estuarine food webs, bivalve molluscs transfer nutrients and pollutants to higher trophic levels. Mercury (Hg) pollution is ubiquitous, but it is especially elevated in estuaries historically impacted by industrial activities, such as those in the U.S. Northeast. Monomethylmercury (MeHg), the organic form of Hg, is highly bioaccumulative and transferable in the food web resulting in the highest concentrations in the largest and oldest marine predators. Patterns of Hg concentrations in marine bivalve molluscs, however, are poorly understood. In this
study, inorganic Hg (iHg), MeHg, and the total Hg (THg) in soft tissues of the northern quahogs (Mercenaria mercenaria), eastern oysters (Crassostrea virginica), and ribbed mussels (Geukensia demissa) from eastern Long Island sound, a temperate estuary of the western North Atlantic Ocean was investigated. In all three species, concentrations of THg remained similar between the four sampling months (May, June, July, and September), and were mostly independent of animal size. In quahogs, MeHg and iHg displayed significant (p < 0.05) positive (iHg in May and June) and negative (MeHg in July and September) changes with shell height. Variability in concentrations of THg, MeHg, and iHg, both inter- and intra-specifically was high and greater in quahogs and oysters (THg: 37, 39%, MeHg: 28, 39%, respectively) than in mussels (THg: 13%, MeHg: 20%). The percentage of THg that was MeHg (%MeHg) was also highly variable in the three species (range: 10-80%), highlighting the importance of measuring MeHg and not only THg in molluscs.