Ice-covered lakes in Antarctica preserve records of regional hydroclimate and harbour extreme ecosystems that may serve as terrestrial analogues for exobiotic environments. Here, we examine the impacts of hydroclimate and landscape on the formation history of Lake Eggers, a small ice-sealed lake, located in the coastal polar desert of McMurdo Sound, Antarctica (78°S). Using ground penetrating radar surveys and three lake ice cores we characterize the ice morphology and chemistry. Lake ice geochemistry indicates that Lake Eggers is fed primarily from local snowmelt that accreted onto the lake surface during runoff events. Radiocarbon ages of ice-encased algae suggest basal ice formed at least 735 ± 20 calibrated years before present (1215 C.E.). Persisting through the Late Holocene, Lake Eggers alternated between periods of ice accumulation and sublimation driven by regional climate variability in the western Ross Sea. For example, particulate organic matter displayed varying δ15N ratios with depth, corresponding to sea ice fluctuations in the western Ross Sea during the Late Holocene. These results suggest a strong climatic control on the hydrologic regime shifts shaping ice formation at Lake Eggers.

中文翻译：

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全新世晚期气候对麦克默多海峡埃格斯湖水文的影响

南极洲冰雪覆盖的湖泊保存了区域水文气候的记录，并拥有极端生态系统，可以作为外生环境的陆地类似物。在这里，我们研究了水文气候和景观对艾格斯湖形成历史的影响，艾格斯湖是一个冰封的小湖，位于南极洲麦克默多海峡（78°S）的沿海极地沙漠。使用探地雷达调查和三个湖冰芯，我们描述了冰的形态和化学性质。湖冰地球化学表明，艾格斯湖主要来自径流事件期间积聚到湖面的当地融雪。冰封藻类的放射性碳年龄表明，基底冰形成于现在（公元 1215 年）至少 735 ± 20 校准年之前。持续到全新世晚期，埃格斯湖在罗斯海西部区域气候变化驱动的冰积累和升华之间交替出现。例如，颗粒有机物显示出不同的 δ15N 与深度的比率，对应于全新世晚期罗斯海西部的海冰波动。这些结果表明，对艾格斯湖冰形成的水文状况变化有很强的气候控制。