Orihel Diane M, Paterson Michael J, Blanchfield Paul J, Bodaly R A Drew, Gilmour Cynthia C, Hintelmann Holger
Clayton H. Riddell Faculty of Environment, Earth, and Resources, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada.
Environ Pollut. 2008 Jul;154(1):77-88. doi: 10.1016/j.envpol.2007.12.030. Epub 2008 Feb 13.
Our objective was to examine how the behavior of atmospheric mercury (Hg) deposited to boreal lake mesocosms changed over time. We added inorganic Hg enriched in a different stable isotope in each of two years, which allowed us to differentiate between Hg added in the first and second year. Although inorganic Hg and methylmercury (MeHg) continued to accumulate in sediments throughout the experiment, the availability of MeHg to the food web declined within one year. This decrease was detected in periphyton, zooplankton, and water mites, but not in gomphid larvae, amphipods, or fish. We suggest that reductions in atmospheric Hg deposition should lead to decreases in MeHg concentrations in biota, but that changes will be more easily detected in short-lived pelagic species than long-lived species associated with benthic food webs.
我们的目标是研究沉积到北方湖泊中型生态系统中的大气汞（Hg）的行为如何随时间变化。我们在两年中的每一年都添加了富集不同稳定同位素的无机汞，这使我们能够区分第一年和第二年添加的汞。尽管在整个实验过程中无机汞和甲基汞（MeHg）在沉积物中持续积累，但食物网中甲基汞的可利用性在一年内下降。在附生植物、浮游动物和水螨中检测到了这种下降，但在大蚊幼虫、双足虾或鱼类中未检测到。我们认为，大气汞沉积的减少应会导致生物群中甲基汞浓度的降低，但与底栖食物网相关的长寿物种相比，在短命的浮游物种中更容易检测到这种变化。
