Chumchal Matthew M, Drenner Ray W, Greenhill Frank M, Kennedy James H, Courville Ashlyn E, Gober Charlie A A, Lossau Luke O
Department of Biology, Texas Christian University, Fort Worth, Texas, USA.
Department of Biological Sciences, University of North Texas, Denton, Texas, USA.
Environ Toxicol Chem. 2017 Aug;36(8):1986-1990. doi: 10.1002/etc.3734. Epub 2017 Feb 2.
Small ponds exist across a permanence gradient, and pond permanence is hypothesized to be a primary determinant of insect community structure and insect-mediated methylmercury (MeHg) flux from ponds to the surrounding terrestrial landscape. The present study describes the first experiment examining the recovery of insect-mediated MeHg flux following a drying disturbance that converted permanent ponds with insectivorous fish to semipermanent ponds without fish. Floating emergence traps were used to collect emergent insects for 10 wk in the spring and summer from 5 ponds with fish (permanent) and 5 ponds that were drained to remove fish, dried, and refilled with water (semipermanent). During the 73-d period after semipermanent ponds were refilled, total MeHg flux from semipermanent ponds was not significantly different than total MeHg flux from permanent ponds, indicating that insect-mediated MeHg flux had rapidly recovered in semipermanent ponds following the drying disturbance. Methylmercury fluxes from dragonflies (Odonata: Anisoptera) and phantom midges (Diptera: Chaoboridae) were significantly greater from newly refilled semipermanent ponds than permanent ponds, but the MeHg fluxes from the other 8 emergent insect taxa did not differ between treatments. The present study demonstrates the impact of drying disturbance and the effect of community structure on the cross-system transport of contaminants from aquatic to terrestrial ecosystems. Environ Toxicol Chem 2017;36:1986-1990. © 2017 SETAC.
小型池塘沿着一个永久性梯度分布，并且池塘永久性被假定为昆虫群落结构以及昆虫介导的甲基汞（MeHg）从池塘向周围陆地景观通量的主要决定因素。本研究描述了首个实验，该实验考察了在一次干燥干扰后昆虫介导的MeHg通量的恢复情况，这次干扰将有食虫鱼类的永久性池塘转变为无鱼的半永久性池塘。在春季和夏季，使用漂浮式诱虫器从5个有鱼的池塘（永久性）和5个排干水以去除鱼类、干燥后再重新注水的池塘（半永久性）中收集羽化昆虫，为期10周。在半永久性池塘重新注水后的73天内，半永久性池塘的总MeHg通量与永久性池塘的总MeHg通量没有显著差异，这表明在干燥干扰后，半永久性池塘中昆虫介导的MeHg通量迅速恢复。新重新注水的半永久性池塘中，蜻蜓（蜻蜓目：差翅亚目）和 phantom 蠓（双翅目：摇蚊科）的甲基汞通量显著高于永久性池塘，但其他8个羽化昆虫类群的MeHg通量在不同处理之间没有差异。本研究证明了干燥干扰的影响以及群落结构对污染物从水生生态系统向陆地生态系统跨系统传输的作用。《环境毒理学与化学》2017年；36：1986 - 1990。© 2017 SETAC。
