Holocene environmental change in Kamchatka: A synopsis
Holocene environmental change in Kamchatka: A synopsis
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DOI：
10.1016/j.gloplacha.2015.09.004
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发表时间：
2015-11-01
影响因子：
3.9
通讯作者：
Hammarlund, D.
中科院分区：
文献类型：
--
作者：
Brooks, S. J.;Diekmann, B.;Hammarlund, D.
我们对俄罗斯远东地区堪察加全新世环境变化的多代理、多地点、古生态研究的结果进行了综合，其细节在卷中的其他地方给出。我们总结了堪察加半岛纬度梯度上五个湖泊和一个泥炭序列的花粉、硅藻、摇蚊和遗迹变形虫组合，以及氧和碳的稳定同位素和沉积物特征的分析结果，以推断环境变化，建立主要的气候作用力和气候遥相关。大多数生物群的组合组成在6.5-62 ka BP、5.2 ka BP、4.0 ka BP和3.5 ka BP之间存在同步变化，表明这些时期是对强烈的区域气候强迫的响应。这些日期对应于全新世最热最高温度(HTM)的最热部分(6.5-6.2ka BP)，新冰川冷却的开始(5.2ka BP)，新冰川最冷和最潮湿的部分(4.0ka BP)，以及3.5ka BP向更温暖和更干燥条件的转变。我们的结果为全新世不同时期不同气团的穿透和支配提供了证据。冬季的冷干期(例如，6.0ka BP)是由西伯利亚高压和阿留申低气压之间相对较弱的气压梯度驱动的，而冬季的凉湿期(例如，新冰期和LIA期间)是由于这两个系统的强度增加而形成的。夏季温暖、干燥的大陆期(例如，2.5ka BP)是由西伯利亚高压减弱驱动的。我们发现堪察加的HTM发生的时间晚于欧亚北极，但与北欧和东西伯利亚的亚北极地区相似。这种逐渐发生的HTM是由于冰后冰盖退化的影响，它调制了欧亚大陆西风风暴路径的路线。一个主要的生态系统驱动因素是西伯利亚矮松，它在全新世期间因冬季降雪增加而向北扩散，并在到达我们研究的湖泊的集水区时引起了水化学变化，并在硅藻和摇蚊组合中做出了反应。我们还检测到火山灰沉积后水化学变化的短期响应，特别是在硅藻组合中。(C)2015年提交人。爱思唯尔出版公司(Elsevier B.V.)
We present a synthesis of the results of a multiproxy, multisite, palaeoecological study of Holocene environmental change in Kamchatka, Far East Russia, details of which are presented elsewhere in the volume. We summarise the results of the analyses of pollen, diatom, chironomid, and testate amoebae assemblages, together with stable isotopes of oxygen and carbon, and sediment characteristics from the sediments of five lakes and a peat succession on a latitudinal gradient of the Kamchatka Peninsula, to infer environmental change and establish the major climate forcers and climatic teleconnections. There are synchronous shifts in the assemblage composition of most of the biota and across most sites at 6.5-62 ka BP, 5.2 ka BP, 4.0 ka BP, and 3.5 ka BP, suggesting a response to strong regional climate forcing at these times. These dates correspond to the warmest part of the Holocene Thermal Maximum (HTM) (6.5-6.2 ka BP), the beginning of the Neoglacial cooling (5.2 ka BP), the coolest and wettest part of the Neoglacial (4.0 ka BP), and a switch to warmer and drier conditions at 3.5 ka BP. Our results provide evidence for the penetration and domination of different air masses at different periods during the Holocene. Cool and dry periods in winter (e.g., at 6.0 ka BP) were driven by a relatively weak pressure gradient between the Siberian High and the Aleutian Low, whereas cool, wet periods in winter (e.g., the Neoglacial and during the LIA) developed when these two systems increased in strength. Warm, dry, continental periods in summer (e.g., at 2.5 ka BP) were driven by a weakening of the Siberian High. We find that the timing of the HTM in Kamchatka is later than in the Eurasian arctic but similar to northern Europe and the sub-arctic part of eastern Siberia. This progressive onset of the HTM was due to the effects of postglacial ice-sheet decay that modulated the routes of westerly storm tracks in Eurasia.A major ecosystem driver was the Siberian dwarf pine Pinus pumila, which spread northward during the Holocene in response to increasing winter snow, and caused water chemistry changes on arrival in the catchments of our study lakes and a response in diatom and chironomid assemblages. We also detect shortterm responses, especially in diatom assemblages, to water chemistry changes following volcanic ash deposits. (C) 2015 The Authors. Published by Elsevier B.V.