Distribution and food-web transfer of mercury in Napoleon and Winam Gulfs, Lake Victoria, East Africa
Distribution and food-web transfer of mercury in Napoleon and Winam Gulfs, Lake Victoria, East Africa
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DOI：
10.1016/s0380-1330(03)70554-1
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发表时间：
2003-01-01
影响因子：
2.2
通讯作者：
Dixon, DG
中科院分区：
文献类型：
--
作者：
Campbell, LM;Hecky, RE;Dixon, DG
测量了维多利亚湖北部拿破仑湾(乌干达)和维纳姆湾(肯尼亚)的食物网和水中的汞(汞)浓度。维多利亚湖的水总汞浓度在1.7~5.8 ng/L之间，而甲基汞浓度在0.2~1 ng/L之间。维多利亚湖的水汞浓度高于温带大湖，包括贝加尔湖、密歇根和安大略省，但顶级捕食性尼罗鱼的THG浓度比温带食鱼性鱼类低。虽然拿破仑湾和威南湾的水汞浓度相似，但拿破仑湾生物群中的THG浓度显著高于威南湾的同一物种，这可能是由于每个海湾的生物地球化学差异所致。尼罗鱼和尼罗罗非鱼的THG浓度随着两个海湾的总长度的增加而持续增加，并且增加的速度相似。由每个食物网的对数-THG与稳定氮同位素值的回归斜率(拿破仑湾和威纳姆湾的斜率分别为0.163和0.165)表明，汞的生物积累速度在其他温带和热带湖泊中观察到的生物积累速度范围内，这表明汞在不同的水生食物网中的生物积累速度相似，无论纬度或物种组成如何。
Mercury (Hg) concentrations were measured for the food webs and water of Napoleon Gulf (Uganda) and Winam Gulf (Kenya) in northern Lake Victoria. Water total mercury (THg) concentrations in Lake Victoria range from 1.7 to 5.8 ng/L, while methylmercury (MeHg) concentrations range from 0.2 to 1 ng/L. Water Hg concentrations in Lake Victoria are higher than in temperate great lakes, including Lakes Baikal, Michigan, and Ontario, but the top predator Nile perch have relatively low THg concentrations compared to temperate piscivorous fish. While the water Hg concentrations are similar between Napoleon and Winam gulfs, the THg concentrations in biota are significantly higher in Napoleon Gulf than in the same species from Winam Gulf, which may be due to biogeochemical differences in each gulf. THg concentrations in Nile perch and Nile tilapia consistently increase with total length in both gulfs and the rates of increase are similar. The rates of THg bioaccumulation, as indicated by the regression slopes of log-THg vs. stable nitrogen isotope values for each food web (slopes of 0.163 and 0.165 for Napoleon and Winam gulfs, respectively), are within the ranges of bioaccumulation rates observed in temperate and tropical lakes elsewhere which suggests that Hg bioaccumulates at a similar rate in diverse aquatic food webs, regardless of latitude or species composition.