Thousands of lakes in a ~ 17,000 km² area around Sudbury (Ontario) acidified (pH < 6) and became metal contaminated as a result of local smelting activities that have taken place since the 1880s. Middle Lake, an urban lake located in Sudbury, acidified to pH ~ 4.3, and was subsequently limed and fertilized in the 1970s and 1980s as part of experimental remediation efforts. Little is known about the long-term impacts of acidification, metal contamination, and subsequent remediation efforts on the benthic invertebrate communities in Middle Lake. Thus, we used paleolimnological methods to examine long-term trends in Chironomidae and Chaoboridae (Diptera) assemblages. Three important chironomid assemblage zones were identified, corresponding to pre-smelting/mining (i.e. reference) conditions, acidification/metal contamination, and subsequent remediation efforts. Acidification led to the increased abundance of acid-tolerant chironomid taxa such as Psectrocladius and Zalutschia, as well as the dominance of Chaoborus americanus indicating the loss of the fish community in the lake between ~ 1920 and ~ 1990. Liming, fertilization, and fish stocking abruptly shifted the chironomid assemblages from Chironomus- to Sergentia-dominated, likely through alterations to habitat quality, food availability, and predation pressure. Fish stocking efforts were clearly visible in the record by the loss of Chaoborus americanus. Following mitigation efforts, chironomid assemblages did not return to their pre-impact state; however, they remained relatively stable after ~ 1990. The recorded shifts in taxonomic composition provide insights into the impacts of smelting operations and remediation efforts on benthic invertebrates, which is important in future lake management and in the future inference of environmental conditions using chironomids in multiple-stressor systems.

中文翻译：

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与以前酸化的中湖（加拿大萨德伯里）的施肥湖和施肥相关的Chironomid组合的长期变化

约17,000公里²中的数千个湖泊²自1880年代以来发生的局部冶炼活动使萨德伯里（安大略省）周围地区酸化（pH <6）并被金属污染。Middle Lake是位于Sudbury的城市湖泊，酸化至pH〜4.3，随后在1970年代和1980年代进行了灰化和施肥，作为实验性修复工作的一部分。对于酸化，金属污染以及随后的治理工作对中湖底栖无脊椎动物群落的长期影响知之甚少。因此，我们使用古脂学方法检查了Chironomidae和Chaoboridae（Diptera）组合的长期趋势。确定了三个重要的手性组装区，分别对应于预熔/采矿（即参考）条件，酸化/金属污染以及随后的修复工作。Psectrocladius和Zalutschia以及美洲潮Chao的优势表明〜1920至〜1990年间湖中鱼类群落的丧失。撒石灰，施肥和鱼类放养使Chironomid组合突然从Chironomus移至以Sergentia为主的种群。通过改变栖息地质量，食物供应和捕食压力。在记录中，由于美洲潮of的丧失，鱼类放养工作显而易见。。经过缓解的努力，手足动物的组合并没有恢复到撞击前的状态。但是，它们在〜1990年之后仍保持相对稳定。分类的组成变化记录了熔炼操作和修复工作对底栖无脊椎动物的影响，这对于将来的湖泊管理以及将来使用多种手性虫的环境条件的推断很重要。压力系统。