Changing nutrient cycling in Lake Baikal, the world's oldest lake.
Changing nutrient cycling in Lake Baikal, the world's oldest lake.
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DOI：
10.1073/pnas.2013181117
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发表时间：
2020-11-03
影响因子：
11.1
通讯作者：
Mackay AW
中科院分区：
文献类型：
--
作者：
Swann GEA;Panizzo VN;Piccolroaz S;Pashley V;Horstwood MSA;Roberts S;Vologina E;Piotrowska N;Sturm M;Zhdanov A;Granin N;Norman C;McGowan S;Mackay AW
贝加尔湖（西伯利亚）是世界上最古老、最深的湖泊，也是联合国教科文组织世界遗产。该湖拥有极高水平的生物多样性和特有性，此外全球五分之一的淡水没有储存在冰盖中，该湖被联合国教科文组织称为“淡水生态系统最杰出的例子”。利用地球化学和气候数据，我们证明了在过去 2000 年到 20 世纪和 21 世纪中，湖泊透光区的养分供应率已上升到前所未有的水平。与增强深层通风的风速增加相关，我们表明这些变化能够改变湖泊初级生产和群落动态，包括地方性物种和世界性物种之间的平衡。贝加尔湖位于西伯利亚东南部的裂谷地带，是世界上最古老、最深、面积最大的湖泊，形成于三千万年前。由于其高度的地方性，该湖被称为“淡水生态系统最杰出的例子”，并于 1996 年被指定为世界遗产，但它及其生态系统日益受到气候变化和人为干扰的威胁。在这里，我们展示了湖中养分循环的记录，该记录来自硅藻的硅同位素组成，硅藻在水生初级生产力中占主导地位。利用该地区的历史记录，我们评估了过去 2000 年自然和人为因素改变该湖生物地球化学循环的程度。我们发现，自 19 世纪中叶以来，由于风动力的变化、冰盖的减少及其对湖泊湖泊过程的相关影响，从深水区到透光区的养分供应率急剧增加。由于未经处理的污水和流域开发带来的压力现在也影响着贝加尔湖的近岸地区，该湖高度流行的生态系统对持续和未来干扰的恢复能力越来越不确定。
Lake Baikal (Siberia) is the world’s oldest and deepest lake and a UNESCO World Heritage Site. Containing an exceptionally high level of biodiversity and endemism, in addition to a fifth of global freshwater not stored in ice sheets, the lake has been cited by UNESCO as the “most outstanding example of a freshwater ecosystem.” Using geochemical and climate data, we demonstrate that rates of nutrient supply to the lake’s photic zone have risen to unprecedented levels in the last 2,000 y through the 20th and 21st centuries. Linked to increases in wind speed enhancing deep ventilation, we show that these changes are capable of altering lake primary production and community dynamics, including the balance between endemic and cosmopolitan species. Lake Baikal, lying in a rift zone in southeastern Siberia, is the world's oldest, deepest, and most voluminous lake that began to form over 30 million years ago. Cited as the “most outstanding example of a freshwater ecosystem” and designated a World Heritage Site in 1996 due to its high level of endemicity, the lake and its ecosystem have become increasingly threatened by both climate change and anthropogenic disturbance. Here, we present a record of nutrient cycling in the lake, derived from the silicon isotope composition of diatoms, which dominate aquatic primary productivity. Using historical records from the region, we assess the extent to which natural and anthropogenic factors have altered biogeochemical cycling in the lake over the last 2,000 y. We show that rates of nutrient supply from deep waters to the photic zone have dramatically increased since the mid-19th century in response to changing wind dynamics, reduced ice cover, and their associated impact on limnological processes in the lake. With stressors linked to untreated sewage and catchment development also now impacting the near-shore region of Lake Baikal, the resilience of the lake’s highly endemic ecosystem to ongoing and future disturbance is increasingly uncertain.
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影响因子：
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通讯作者：
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