The fate of Lake Baikal: how climate change may alter deep ventilation in the largest lake on Earth
The fate of Lake Baikal: how climate change may alter deep ventilation in the largest lake on Earth
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DOI：
10.1007/s10584-018-2275-2
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发表时间：
2018-10-01
期刊：
影响因子：
4.8
通讯作者：
Toffolon, Marco
中科院分区：
文献类型：
--
作者：
Piccolroaz, Sebastiano;Toffolon, Marco
贝加尔湖是地球上最古老、最深、容量最大的淡水湖。尽管湖水深度巨大，但由于温压不稳定，偶尔（几乎每年两次）大量表层冷水和含氧水下沉至湖底，从而对整个湖的生态产生影响。使用最小一维模型来研究主要外部强迫（即风和湖面温度）的变化如何影响这种深层通风机制。考虑到 IPCC RCP8.5 和一些理想化情景，评估了气候变化的影响，并通过以下方式进行量化：(i) 估计年平均下降流量和温度；(ii) 分析垂直温度和溶解氧剖面。结果表明，最强的影响是由风力的变化产生的，而深层通风可以抵抗湖面温度的上升。事实上，深度通风的季节可以因湖泊变暖而及时改变，但其持续时间不会发生显着改变。总体而言，结果表明贝加尔湖对气候变化非常敏感，以至于这个独特的湖泊系统的生态系统和水质可能会受到深刻的干扰。
Lake Baikal is the oldest, deepest, and most voluminous freshwater lake on Earth. Despite its enormous depth, episodically (almost twice a year) large amounts of surface, cold, and oxygenated water sink until the bottom of the lake due to thermobaric instability, with consequent effects on the ecology of the whole lake. A minimal one-dimensional model is used to investigate how changes in the main external forcing (i.e., wind and lake surface temperature) may affect this deep ventilation mechanism. The effect of climate change is evaluated considering the IPCC RCP8.5 and some idealized scenarios and is quantified by (i) estimating the mean annual downwelling volume and temperature and (ii) analyzing vertical temperature and dissolved oxygen profiles. The results suggest that the strongest impact is produced by alterations of wind forcing, while deep ventilation is resistant to rising lake surface temperature. In fact, the seasons when deep ventilation can occur can be shifted in time by lake warming, but not dramatically modified in their duration. Overall, the results show that Lake Baikal is sensible to climate change, to an extent that the ecosystem and water quality of this unique lacustrine system may undergo profound disturbances.