Institute of Ecology, University of Innsbruck , Technikerstraße 25, 6020 Innsbruck, Austria.
Environ Sci Technol. 2014 Jun 3;48(11):6192-200. doi: 10.1021/es500180c. Epub 2014 May 15.
Despite the fact that rock glaciers are one of the most common geomorphological expressions of mountain permafrost, the impacts of their solute fluxes on lakes still remain largely obscure. We examined water and sediment chemistry, and biota of two neighboring water bodies with and without a rock glacier in their catchments in the European Alps. Paleolimnological techniques were applied to track long-term temporal trends in the ecotoxicological state of the water bodies and to establish their baseline conditions. We show that the active rock glacier in the mineralized catchment of Lake Rasass (RAS) represents a potent source of acid rock drainage that results in enormous concentrations of metals in water, sediment, and biota of RAS. The incidence of morphological abnormalities in the RAS population of Pseudodiamesa nivosa, a chironomid midge, is as high as that recorded in chironomid populations inhabiting sites heavily contaminated by trace metals of anthropogenic origin. The incidence of morphological deformities in P. nivosa of ∼70% persisted in RAS during the last 2.5 millennia and was ∼40% in the early Holocene. The formation of RAS at the toe of the rock glacier most probably began at the onset of acidic drainage in the freshly deglaciated area. The present adverse conditions are not unprecedented in the lake's history and cannot be associated exclusively with enhanced thawing of the rock glacier in recent years.
尽管岩冰河是山区多年冻土最常见的地貌表现形式之一，但它们的溶质通量对湖泊的影响仍然很大程度上不为人知。我们研究了两个相邻水体的水和沉积物化学以及生物群，这些水体的流域内有和没有岩冰河。古湖泊学技术被用来追踪水体生态毒理学状态的长期时间趋势，并确定它们的基线条件。我们表明，拉萨斯湖（RAS）矿化流域中的活跃岩冰河是酸性岩石排水的有力来源，导致水中、沉积物中和生物群中金属浓度极高。在 Pseudodiamesa nivosa 的 RAS 种群中，形态异常的发生率高达在受人为来源痕量金属严重污染的地点栖息的摇蚊种群中记录到的水平。在过去的 2500 年中，RAS 中 P. nivosa 的形态畸形发生率约为 70%，在早全新世约为 40%。岩冰河在冰河脚下形成的时间很可能是在新冰川融化的地区开始出现酸性排水的时候。目前的不利条件在湖泊历史上并不是前所未有的，不能仅与近年来岩冰河的融冻增强联系在一起。
