Glacier retreat as a consequence of climate change influences freshwater ecosystems in manifold ways, yet the physical and chemical bases of these effects are poorly studied. Here, we characterize how water temperature differs between alpine lakes with and without direct glacier influence on seasonal and diurnal timescales. Using high temporal resolution monitoring of temperature in 4 lakes located in a catchment influenced by glacier retreat, we reported unexpectedly high surface temperatures, even in proglacial lakes located 2600 m a.s.l. Cold glacier meltwater and low nighttime air temperatures caused a distinct diurnal pattern of water temperature in the water column of glacier-influenced lakes. Precipitation onto glacier surfaces apparently leads to rapid cooling of the glacier-fed lakes and disrupts the thermal stratification with several mixing events during the summer. Taken together, these mechanisms contribute to the unique seasonal and diurnal dynamics of glacier-influenced lakes that contrast with the typical dimictic pattern of clear alpine lakes and represent an example of discontinuous cold polymictic lake type. This work contributes to the basic description of how climate and meteorology affect the physical properties of an increasingly common lake type.

气候变化导致的冰川退缩以多种方式影响淡水生态系统，但这些影响的物理和化学基础研究很少。在这里，我们描述了高山湖泊之间水温的差异，无论有无冰川对季节和昼夜时间尺度的直接影响。使用高时间分辨率监测位于受冰川退缩影响的集水区的 4 个湖泊的温度，我们报告了出乎意料的高地表温度，即使在位于 2600 m asl 的前冰河湖中 寒冷的冰川融水和低夜间气温导致了明显的水温昼夜模式在受冰川影响的湖泊的水柱中。冰川表面的降水显然导致冰川补给的湖泊迅速冷却，并在夏季通过几次混合事件破坏了热分层。总之，这些机制促成了受冰川影响的湖泊独特的季节性和昼夜动态，这与清澈的高山湖泊的典型二元模式形成鲜明对比，代表了不连续的冷多元湖类型的一个例子。这项工作有助于基本描述气候和气象如何影响日益常见的湖泊类型的物理特性。这些机制促成了受冰川影响的湖泊独特的季节性和昼夜动态，这与清澈的高山湖泊的典型二元模式形成鲜明对比，并代表了不连续的冷多元湖泊类型的一个例子。这项工作有助于基本描述气候和气象如何影响日益常见的湖泊类型的物理特性。这些机制促成了受冰川影响的湖泊独特的季节性和昼夜动态，这与清澈的高山湖泊的典型二元模式形成鲜明对比，并代表了不连续的冷多元湖泊类型的一个例子。这项工作有助于基本描述气候和气象如何影响日益常见的湖泊类型的物理特性。