Late-Holocene climate dynamics recorded in the peat bogs of Tierra del Fuego, South America
Late-Holocene climate dynamics recorded in the peat bogs of Tierra del Fuego, South America
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DOI：
10.1177/0959683615609756
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发表时间：
2016-03
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通讯作者：
S. van Bellen;D. Mauquoy;Paul D.M. Hughes;T. Roland;T. Daley;N. Loader;F. Street-Perrott;Emma M. Rice;V. Pancotto;Richard J Payne
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作者：
S. van Bellen;D. Mauquoy;Paul D.M. Hughes;T. Roland;T. Daley;N. Loader;F. Street-Perrott;Emma M. Rice;V. Pancotto;Richard J Payne
火地岛的疏养泥炭沼泽位于南部西风带（SWWB）内，主导着该地区的气候变化。我们从三个泥炭沼泽重建了晚全新世的地下水位深度，目的是将这些记录与区域气候的变化联系起来。地下水位深度通过对晚期变形虫组合的分析来量化，并使用区域传递函数来推断过去的地下水位深度。在过去的2000年里，无足变形虫的组合相对稳定，以毛羽变形虫和毛羽变形虫为主，而在每个剖面的顶部都有增加的Assulina muscorum和其他Euglyphida。多变量分析表明，地下水位深度仍然是解释TiA12岩心组合的主要环境变量，但对其他两个岩心的重建并不显著。与组合的低变率一致，地下水位在过去2000年中相对稳定。在~1400 ~ 900 cal. BP之间发现了稍湿润的条件，并且在所有三个泥炭剖面中都重建了明显的近期干移。考虑到区域气候背景，最近的这种转变可能是由降水减少和与西南偏流重要性增加相关的变暖条件所强迫的。尽管如此，我们不能排除自1970年代末以来臭氧层局部退化造成的更高的UV-B辐射的影响，这可能对巴塔哥尼亚南部地区的相对存在有额外的影响。
The ombrotrophic peat bogs of Tierra del Fuego are located within the southern westerly wind belt (SWWB), which dominates climate variability in this region. We have reconstructed late-Holocene water-table depths from three peat bogs and aimed to relate these records to shifts in regional climate. Water-table depths were quantified by the analysis of testate amoeba assemblages, and a regional transfer function was used to infer past water-table depths. During the last 2000 years, testate amoeba assemblages have been relatively stable, with a dominance of Difflugia pulex and Difflugia pristis type, and an increase in Assulina muscorum and other Euglyphida at the top of each section. Multivariate analyses show that water-table depth remained the main environmental variable explaining assemblages along the TiA12 core, but reconstructions were not significant for the two other cores. In line with the low variability in assemblages, water tables were relatively stable during the last 2000 years. Slightly wetter conditions were found between ~1400 and 900 cal. BP and a pronounced recent dry shift was reconstructed in all of the three peat profiles. Considering the regional climatic context, this recent shift may have been forced by a decrease in precipitation and warmer conditions linked to an increase in the importance of the SWWB. Nevertheless, we cannot exclude the influence of higher UV-B radiation resulting from the local degradation of the ozone layer since the late 1970s, which may have had an additional effect on the relative presence of A. muscorum in the southern Patagonian region.