Norwegian Institute for Nature Research, Gaustadalléen 21, NO-0349 Oslo, Norway.
Norwegian Public Roads Administration, Environmental Assessment Section, P.O. box 8142 Dep., NO-0033 Oslo, Norway; Norwegian University of Life Sciences, Department of Plant and Environmental Sciences, P.O. box 5003, NO-1432 Ås, Norway.
Sci Total Environ. 2014 Apr 15;478:36-47. doi: 10.1016/j.scitotenv.2014.01.076. Epub 2014 Feb 12.
Numerous boreal lakes across the Northern Hemisphere recovering from acidification are experiencing a simultaneous increase in chloride (Cl) concentrations from road salting. Increasing Cl may have profound effects on the lake ecosystem. We examine if an increase in Cl from road salting has modified the recovery of the microcrustacean community in an acidified boreal lake undergoing chemical recovery (study lake). Results from the study lake were compared with an acidified "reference lake". The community changed during the study period in the study lake mainly driven by the reduction in acidification pressure. Despite the community changes and an increase in species richness, the absence of several acid sensitive species, previously occurring in the lake, indicates a delayed biological recovery relative to the chemical recovery. Moreover, changes in occurrence of acid sensitive and acid tolerant species indicated that the biological recovery was slower in the study lake compared to the "reference". Although recurrent episodes of high aluminum and low pH and decreasing Ca are likely important factors for the delay, these do not explain, for instance, the shift from Cyclops scutifer to Bosmina longispina in the study lake. Although the contribution of Cl was not significant, the correlation between Cl and the variation in microcrustacean community was twice as high in the study lake compared to the "reference". We argue that small, sheltered forest lakes may be especially sensitive to increased Cl levels, through changes in pattern of stratification, thus providing a mechanism for the shift from C. scutifer to B. longispina. The reduction of the acidification pressure seems to override the Cl effects on microcrustaceans at low Cl levels in salt-affected lakes recovering from acidification. However, prognoses for growing traffic and increasing road salting raise concern for many recovering lakes located in proximity to roads and urbanized areas.
北半球众多受酸化影响的北方湖泊正在从道路盐分中同时经历氯（Cl）浓度的增加。增加 Cl 可能对湖泊生态系统产生深远影响。我们研究了道路盐分增加是否改变了正在进行化学恢复的酸化北方湖泊中微型甲壳动物群落的恢复情况（研究湖泊）。研究结果与酸化的“参考湖泊”进行了比较。在研究期间，研究湖泊中的群落主要受到酸化压力降低的驱动而发生变化。尽管群落发生了变化，物种丰富度增加，但由于以前存在于湖泊中的几种对酸敏感的物种缺失，表明相对于化学恢复，生物恢复滞后。此外，对酸敏感和耐酸物种出现的变化表明，与“参考”相比，研究湖泊中的生物恢复较慢。尽管反复出现高铝和低 pH 值以及 Ca 减少可能是延迟的重要因素，但这些因素并不能解释，例如，研究湖泊中从 Cyclops scutifer 到 Bosmina longispina 的转变。尽管 Cl 的贡献并不显著，但与“参考”相比，Cl 与微型甲壳动物群落变化之间的相关性在研究湖泊中要高两倍。我们认为，小而受保护的森林湖泊可能对 Cl 水平升高特别敏感，这会改变分层模式，从而为从 C. scutifer 到 B. longispina 的转变提供一种机制。在受酸化影响的恢复湖泊中，低 Cl 水平下，酸化压力的降低似乎会超过 Cl 对微型甲壳动物的影响。然而，随着交通量的增加和道路撒盐量的增加，许多位于道路和城市地区附近的恢复湖泊的前景令人担忧。
