Present-day variability and Holocene dynamics of permafrost-affected lakes in central Yakutia (Eastern Siberia) inferred from diatom records
Present-day variability and Holocene dynamics of permafrost-affected lakes in central Yakutia (Eastern Siberia) inferred from diatom records
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根据硅藻记录推断雅库特中部（东西伯利亚）受永久冻土影响的湖泊的当今变化和全新世动态
DOI：
10.1016/j.quascirev.2012.06.020
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发表时间：
2012
影响因子：
4
通讯作者：
M. Ulrich
中科院分区：
文献类型：
--
作者：
L. Pestryakova;U. Herzschuh;S. Wetterich;M. Ulrich
热岩溶湖泊被认为是周期性发展的，由气候触发的过程驱动，并由可能触发湖泊排水的内部反馈维持。然而，这些循环的持续时间仍然不确定，以及它们是否影响到千年时间尺度上永久冻土区湖泊生态系统的稳定。我们的研究结合了对现代湖泊间变异性的调查和对个别湖泊长期发展的研究。我们研究了雅库特中部(东西伯利亚)101个不同成因的湖泊的物理化学和硅藻组成，包括热岩溶湖泊、河流侵蚀热岩溶湖泊、河流侵蚀湖泊和沙丘湖泊。通过多响应排列过程、指示物种分析和冗余分析，我们发现湖泊成因与环境和硅藻特征的现代变异性之间存在显著的关系。环境参数与硅藻数据的变化也表现出显著的相关性，它们可能在很大程度上对此负有责任。镁和SO4浓度以及pH和水深被认为是最重要的参数，对硅藻数据的影响几乎与整个环境参数集的影响一样大。因此，我们能够建立一个稳健的镁硅藻转移函数，然后将其应用于三个全新世湖泊记录。根据这些重建，再加上对硅藻记录的一般解释(例如，包括底栖/附生和浮游类群之间的比率)，我们已经能够推断，所有这三个湖泊都表现出(1)没有干燥事件的连续记录，(2)全新世早期的高湖水位，(3)百年至千年的尺度变异性，以及(4)全新世早期的高度变异性，但在晚全新世期间相当稳定(这一特征也在世界其他地点已知)。因此，我们得出结论，这三个湖泊的发育主要是由气候直接驱动的，而不是由融化的湖泊循环驱动的。
Thermokarst lakes are assumed to develop cyclically, driven by processes that are triggered by climate and maintained by internal feedbacks that may trigger lake drainage. However, the duration of these cycles remains uncertain, as well as whether or not they affect the stabilization of lake ecosystems in permafrost regions over millennial time scales. Our research has combined investigations into modern lake-to-lake variability with a study of the long-term development of individual lakes. We have investigated the physico-chemical and diatom compositions of a set of 101 lakes with a variety of different origins in central Yakutia (Eastern Siberia), including thermokarst lakes, fluvial-erosion thermokarst lakes, fluvial-erosion lakes, and dune lakes. We found a significant relationship between lake genesis and the present-day variability in environmental and diatom characteristics, as revealed by multi-response permutation procedures, indicator species analyses, and redundancy analyses. Environmental parameters also exhibit a significant correlation with variations in the diatom data, for which they may have been to a substantial extent responsible. Mg and SO4concentrations, together with pH and water depth, were identified as the most important parameters, influencing the variations in the diatom data almost as much as the entire environmental parameter set. We were therefore able to establish a robust Mg-diatom transfer function, which was then applied to three Holocene lake records. From these reconstructions, together with a general interpretation of the diatom record (including, e.g., the ratio between benthic/epiphytic and planktonic taxa), we have been able to infer that all three of these lakes show (1) a continuous record with no desiccation events, (2) high lake water-levels during the early Holocene, (3) centennial to millennial scale variability, and (4) high levels of variability during the early Holocene but rather stable conditions during the late Holocene (a feature that is also known from other sites around the world). We therefore concluded that the development of these three lakes was mainly driven directly by the climate, rather than by thaw lake cycling.