Groupe de recherche interuniversitaire en limnologie, Département de sciences biologiques, Université de Montréal, Montréal, Québec H3C 3J7, Canada.
Groupe de recherche interuniversitaire en limnologie, Département de sciences biologiques, Université de Montréal, Montréal, Québec H3C 3J7, Canada.
Environ Pollut. 2011 Jan;159(1):10-17. doi: 10.1016/j.envpol.2010.09.034.
We examined habitat-specific bioaccumulation of methylmercury (MeHg) in aquatic food webs by comparing concentrations in pelagic zooplankton to those in littoral macroinvertebrates from 52 mid-latitude lakes in North America. Invertebrate MeHg concentrations were primarily correlated with water pH, and after controlling for this influence, pelagic zooplankton had significantly higher MeHg concentrations than littoral primary consumers but lower MeHg than littoral secondary consumers. Littoral primary consumers and pelagic zooplankton are two dominant prey for fish, and greater MeHg in zooplankton is likely sufficient to increase bioaccumulation in pelagic feeders. Intensive sampling of 8 lakes indicated that habitat-specific bioaccumulation in invertebrates (of similar trophic level) may result from spatial variation in aqueous MeHg concentration or from more efficient uptake of aqueous MeHg into the pelagic food web. Our findings demonstrate that littoral-pelagic differences in MeHg bioaccumulation are widespread in small mid-latitude lakes.
我们通过比较北美 52 个中纬度湖泊的浮游动物和滨岸大型无脊椎动物体内甲基汞（MeHg）的浓度，研究了水生食物网中特定生境的甲基汞生物积累情况。无脊椎动物体内的 MeHg 浓度主要与水体 pH 值相关，在控制了这一影响后，浮游动物体内的 MeHg 浓度明显高于滨岸初级消费者，但低于滨岸次级消费者。滨岸初级消费者和浮游动物是鱼类的两种主要食物，浮游动物体内的 MeHg 浓度较高，可能足以增加海洋食源动物的生物积累。对 8 个湖泊的密集采样表明，无脊椎动物体内的生境特异性生物积累（具有相似营养级）可能是由于水体中 MeHg 浓度的空间变化，或是由于更有效地将水相 MeHg 吸收到浮游食物网中所致。我们的研究结果表明，在小型中纬度湖泊中，MeHg 生物积累在滨岸-浮游之间的差异普遍存在。
