Department of Biology, Texas Christian University, Winton Scott Room 401, 2800 South University Drive, Fort Worth, Texas 76129, United States.
Environ Sci Technol. 2013 Feb 5;47(3):1614-9. doi: 10.1021/es303330m. Epub 2013 Jan 16.
We examined the effects of fish predation on emergent insect-mediated methyl mercury (MeHg) flux across a gradient of MeHg contamination in experimental ponds. Emergent insects were collected from ponds with (n = 5) and without fish (n = 5) over a six week period using floating emergence traps. We found that the potential for MeHg flux increased with Hg contamination levels of the ponds but that the realized MeHg flux of individual insect taxa was determined by fish presence. Fish acted as size-selective predators and reduced MeHg flux by suppressing emergence of large insect taxa (dragonflies and damselflies) but not small insect taxa (chironomids and microcaddisflies). MeHg flux by small insect taxa was correlated with concentrations of MeHg in terrestrial spiders along the shorelines of the study ponds, demonstrating for the first time the cross-system transport of MeHg by emergent insects to a terrestrial spider.
我们研究了鱼类捕食对实验池塘中甲基汞（MeHg）通量的影响，这些池塘的 MeHg 污染程度存在梯度。在六周的时间里，我们使用漂浮式昆虫诱捕器从有鱼（n = 5）和没有鱼（n = 5）的池塘中收集了水生昆虫。我们发现，MeHg 通量的潜在能力随着池塘中 Hg 污染水平的升高而增加，但个别昆虫类群的实际 MeHg 通量则由鱼类的存在决定。鱼类作为大小选择性捕食者，通过抑制大型昆虫类群（蜻蜓和豆娘）的出现来降低 MeHg 通量，但不影响小型昆虫类群（摇蚊和毛翅目）。小型昆虫类群的 MeHg 通量与研究池塘岸边陆地蜘蛛中的 MeHg 浓度相关，这首次证明了水生昆虫向陆地蜘蛛的跨系统 MeHg 传输。
