Department of Chemistry and River Studies Center, University of Wisconsin-La Crosse, La Crosse, WI 54601, USA.
Ecotoxicology. 2011 Oct;20(7):1520-9. doi: 10.1007/s10646-011-0733-y. Epub 2011 Jul 7.
While mercury is a health hazard to humans and wildlife, the biogeochemical processes responsible for its bioaccumulation in pelagic food webs are still being examined. Previous studies have indicated both "bottom-up" control of piscivorous fish Hg content through methylmercury.(MeHg) supply, as well as site-specific trophic factors. We evaluated ten studies from the western Great Lakes region to examine the similarity of MeHg trophic transfer efficiency within the pelagic food web, and assessed regional-scale spatial variability. Analyses of bioaccumulation and biomagnification factors between water, seston, zooplankton, and preyfish indicated that the largest increases in MeHg occurred at the base of the food web, and that the relative extent of trophic transfer was similar between sites. Positive correlations were observed between aqueous unfiltered MeHg, total Hg, and dissolved organic carbon, and measures of the efficiency of MeHg trophic transfer were consistent across widely disparate systems (both natural and experimentally manipulated) throughout North America. Such similarity suggests that the aqueous supply of MeHg is largely controlling bioaccumulation in pelagic food webs, while local, lake-specific variability can result from an array of trophic (biological) factors.
虽然汞对人类和野生动物健康构成危害，但负责其在海洋浮游食物网中生物积累的生物地球化学过程仍在研究中。先前的研究表明，通过甲基汞（MeHg）供应以及特定地点的营养因素，对食鱼性鱼类 Hg 含量进行了“自上而下”的控制。我们评估了来自大湖区西部的十项研究，以检验海洋浮游食物网中 MeHg 营养传递效率的相似性，并评估区域尺度的空间变异性。对水、悬浮泥沙、浮游动物和猎物鱼之间的生物积累和生物放大因子的分析表明，MeHg 在食物网的基础上增加最多，并且营养传递的相对程度在各个地点之间相似。在水相中未过滤的 MeHg、总 Hg 和溶解有机碳之间观察到正相关，并且 MeHg 营养传递效率的衡量标准在整个北美的各种不同系统（自然和实验操作）中是一致的。这种相似性表明，MeHg 的水相供应在很大程度上控制了海洋浮游食物网中的生物积累，而局部的、特定于湖泊的变异性可能是由于一系列营养（生物）因素造成的。
