Lake Mogilnoe is a rare example of an anchialine lake (with subterranean connection to the ocean) in the Arctic, a refuge for landlocked populations of marine organisms. The lake has been the subject of intensive studies since the end of the 19th century. Here we demonstrate that between the 2003–07 and 2015–18 observation periods this permanently stratified lake experienced significant changes. The surface salinity increased and exceeded the tolerance limits of many freshwater organisms. The bottom anoxia expanded from one-fifth to one-third of the lake volume. Such a turn in stratification affected both composition and distribution of biota: freshwater zooplanktonic species virtually disappeared, while benthic communities shifted to shallower depths. Although recent changes in the lake stratification are consistent with the long-term trend, their scale is much larger than has been observed during the past 120 years. It was earlier considered that the lake dynamics were mainly affected by human activity in the vicinity of the lake. However, lack of human activity around Mogilnoe during last decades persuades us to search for the natural causes of the recorded changes.

中文翻译：

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到 21 世纪初，Mogilnoe 海洋湖（基尔丁岛、巴伦支海）分层的快速不可预测变化

Mogilnoe 湖是北极地区一个罕见的无水湖（与海洋相连的地下），是内陆海洋生物种群的避难所。自 19 世纪末以来，该湖一直是深入研究的主题。在这里，我们证明了在 2003-07 和 2015-18 观察期之间，这个永久分层的湖泊经历了重大变化。表面盐度增加并超过了许多淡水生物的耐受极限。底部缺氧从湖水量的五分之一扩大到三分之一。这种分层的转变影响了生物群的组成和分布：淡水浮游动物物种几乎消失了，而底栖生物群落转移到更浅的深度。虽然近期湖泊分层变化与长期趋势一致，它们的规模比过去 120 年观察到的要大得多。早先认为湖泊动态主要受湖泊附近人类活动的影响。然而，过去几十年莫吉尔诺周围人类活动的缺乏说服我们寻找记录变化的自然原因。