Lake diatom response to climate change and sedimentary events on the southeastern Tibetan Plateau during the last millennium
Lake diatom response to climate change and sedimentary events on the southeastern Tibetan Plateau during the last millennium
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近千年来青藏高原东南部湖泊硅藻对气候变化和沉积事件的响应
DOI：
10.1016/j.quascirev.2020.106409
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发表时间：
2020
影响因子：
4
通讯作者：
Kai Li
中科院分区：
文献类型：
--
作者：
Mengna Liao;Ulrike Herzschuh;Yongbo Wang;Xingqi Liu;Jian Ni;Kai Li
青藏高原东南部的气候变化对湖泊生态系统产生影响。然而，气候和非气候因素的平行变化以及集水过程对信号的调解使气候变化对湖泊生态系统影响的评估复杂化，需要长期和高分辨率的多变量时间序列。在这里，我们提出了一个硅藻记录在Basomtso湖，TP东南部，涵盖了1083-2012 CE与次十年分辨率，我们涉及到潜在的气候和非气候因素的可用代理。记录以浮游硅藻为主，其组成变化主要表现为大细胞和小细胞Pantocsekiella ocellata以及浮游硅藻和底栖硅藻之间的交替。硅藻组合显示，自世纪末以来，眼斑原甲藻（大型）数量减少，而眼斑原甲藻（小型）数量增加，硅藻生产力增加，反映了百年时间尺度上的变化，这种变化主要是随温度升高而变化的。我们记录了几个变化的比例，浮游生物和底栖物种丰度（P：B）的一个亚十年或十年的时间尺度。P：B的显著减少是高能流引起的快速沉积事件的结果。交叉相关分析揭示了硅藻和陆地植被对区域温度变化的同步响应和异步响应，表明湖泊硅藻对东南TP气候变化的时间和幅度有更高的探测潜力。结果表明，在巴松措，以及在其他山区湖泊的TP东南部的水生生态系统，可能会受到更大的风险比陆地生态系统在未来的气候情景下政权转移。
Climate change on the southeastern Tibetan Plateau (TP) is assumed to impact lake ecosystems. However, parallel changes in climate and non-climate factors and mediation of signals by catchment processes complicate the assessment of climate-change effects on lake ecosystems requiring long-term and high resolution multi-variable time-series. Here we present a diatom record from sediments in the lake Basomtso, southeastern TP, covering the period 1083–2012 CE with sub-decadal resolution which we relate to available proxies for potential climate and non-climate factors. The record is dominated by planktonic species and the compositional change is mainly characterized by alternations between big- and small-celledPantocsekiella ocellataand between planktonic and benthic diatom species. The diatom assemblages show a decrease ofP. ocellata(big form) since the end of 17th century and an increase ofP. ocellata(small form) as well as an increase in diatom productivity, reflecting changes on a centennial timescale which mainly follow temperature increase. We recorded several changes in the ratio of planktonic to benthic species abundance (P: B) on a sub-decadal or decadal timescale. Noticeable decreases in P: B were a result of rapid sedimentary events caused by high energy flows. Cross-correlation analyses reveal synchronous responses of diatoms and asynchronous responses of terrestrial vegetation to regional temperature change, indicating a higher potential of lake diatoms to detect the timing and magnitude of climate shifts on the southeastern TP. The results imply that aquatic ecosystems in Basomtso, as well as in other mountain lakes on the southeastern TP, are probably subject to a larger risk of regime shift than terrestrial ecosystems under future climate scenarios.