Impact of monsoons, temperature, and CO2 on the rainfall and ecosystems of Mt. Kenya during the Common Era
Impact of monsoons, temperature, and CO2 on the rainfall and ecosystems of Mt. Kenya during the Common Era
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DOI：
10.1016/j.palaeo.2013.12.037
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发表时间：
2014-02
期刊：
影响因子：
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通讯作者：
B. Konecky;J. Russell;Y. Huang;M. Vuille;L. Cohen;F. Street-Perrott
中科院分区：
文献类型：
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作者：
B. Konecky;J. Russell;Y. Huang;M. Vuille;L. Cohen;F. Street-Perrott
冰川和全新世早期沉积物从湖泊山。肯尼亚记录了山地水文、生态系统和碳循环对过去温度和大气CO2浓度变化的强烈反应。然而，很少有人知道的气候和生态系统的变化。尽管有越来越多的证据表明，在过去的一千年里，东非低地发生了重大的气候变化，最近还观察到东非高地的高山冰川退缩，但肯尼亚在共同时代（过去~ 2000年）的气候变化仍然存在。本文报道了200年以来圣湖沉积物中保存的陆生植物蜡化合物（δDwax、δ 13 Cwax）的氢、碳同位素组成的新记录。直到世纪末。我们发现，Mt。在过去的1800年里，肯尼亚的气候变化很大。公元200年左右圣湖的干旱，公元700年，1100C.与肯尼亚中部和乌干达/刚果的类似干旱相一致，表明在共同时代早期，印度和大西洋季风的失败导致了整个赤道东非的大范围干旱。相比之下，在圣湖在过去的500年的干湿期显示与东非其他网站的纬向和纬向对比，这表明强烈的空间异质性，可能是由于独立的大西洋和印度季风的盈亏。在~ 1870 C. E.之后明显干燥。这表明，目前在圣湖观察到的干旱阶段可能已经开始之前的世纪，大约在当时的撤退山。肯尼亚的冰川最早是由欧洲探险家发现的。山肯尼亚的植被对最近的这些气候变化反应强烈，突出表明热带山地气候和生态系统对区域和全球气候模式特别敏感，并强调迫切需要了解未来气候变化对这一高度敏感地区的潜在影响。
Glacial and early Holocene-age sediments from lakes on Mt. Kenya have documented strong responses of montane hydrology, ecosystems, and carbon cycling to past changes in temperature and atmospheric CO2concentrations. However, little is known about climate and ecosystem variations on Mt. Kenya during the Common Era (the past ~ 2000 years), despite mounting evidence for significant climate changes in the East African lowlands during the past millennium and recent observations of alpine glacier retreat in the East African highlands. We present a new, high-resolution record of the hydrogen and carbon isotopic composition of terrestrial plant wax compounds (δDwax, δ13Cwax) preserved in the sediments of Sacred Lake from 200C.E. to the end of the 20th century. We find that Mt. Kenya's climate was highly variable during the past 1800 years. Droughts at Sacred Lake around ~ 200C.E., 700C.E., and 1100C.E. align with similar droughts in central Kenya and Uganda/Congo, indicating that failures of both the Indian and Atlantic monsoons caused widespread drought throughout equatorial East Africa during the early Common Era. In contrast, dry and wet periods at Sacred Lake during the past 500 years show meridional and zonal contrasts with other sites in East Africa, suggesting strong spatial heterogeneity, possibly due to independent waxing and waning of the Atlantic and Indian monsoons. Pronounced drying after ~ 1870C.E. suggests that the current dry phase observed at Sacred Lake may have begun prior to the 20th century, around the time when the retreat of Mt. Kenya's glaciers was first observed by European explorers. Mt. Kenya's vegetation responded strongly to these recent climate changes, highlighting the particular sensitivity of tropical montane climate and ecosystems to regional and global climate patterns, and underscoring the critical need to understand potential impacts of future climate change scenarios on this highly sensitive region.