Oxygen isotopes in tree rings show good coherence between species and sites in Bolivia
Oxygen isotopes in tree rings show good coherence between species and sites in Bolivia
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DOI：
10.1016/j.gloplacha.2015.09.008
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发表时间：
2015-10-01
影响因子：
3.9
通讯作者：
Brienen, Roel J. W.
中科院分区：
文献类型：
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作者：
Baker, Jessica C. A.;Hunt, Sarah F. P.;Brienen, Roel J. W.
一个树轮氧同位素（三角洲O-18（TR））年表从一个物种（Cedrela odorata）生长在一个单一的网站已被证明是一个敏感的代理亚马逊流域的降雨量，从而允许重建的降水量在一个地区的气象记录是短暂的和稀缺的。虽然这些结果表明，亚马逊河三角洲O-18（TR）记录应该具有大尺度（>100公里）的空间一致性，但这一点尚未得到检验。此外，它是感兴趣的调查是否其他，可能寿命较长，物种同样记录亚马逊降水的年际变化，并可用于开发气候敏感的同位素年表。在这项研究中，我们测量了来自玻利维亚的七个低地和一个高地树种的树木年轮中的δ O-18。我们的“同位素交叉定年法”证实了放射性碳“炸弹峰”日期，并有可能大大促进发展的三角洲O-18（TR）记录在热带地区，确定测年误差，并检查年轮形成在热带树木。七个低地物种中有六个与飞机草显著相关，表明δ O-18（TR）的变化在非常不同的物种之间具有一致的印记，最有可能是由于源水δ O-18对δ O-18（TR）的主导影响。此外，我们还表明，δ O-18（TR）系列在物种内部和物种之间的大距离上具有一致性。两个C的比较来自相距数百公里的地点的odorata delta O-18（TR）年表显示出非常强的相关性（r = 0.80，p < 0.001，1901-2001），在低地香樟树和生长在较远的高原上的多鳞草树之间发现了（但较弱的）关系（r = 0.39，p < 0.01，1931-2001）。这种大规模的一致性三角洲O-18（TR）的记录可能是由一个强大的空间一致性触发的降水三角洲O-18由于大规模的控制。这些结果突出了三角洲O-18（TR）作为降水代理的强度，并为南美洲降水重建的时空扩展开辟了道路。(C)2015年，作者。由爱思唯尔公司出版
A tree ring oxygen isotope (delta O-18(TR)) chronology developed from one species (Cedrela odorata) growing in a single site has been shown to be a sensitive proxy for rainfall over the Amazon Basin, thus allowing reconstructions of precipitation in a region where meteorological records are short and scarce. Although these results suggest that there should be large-scale (>100 km) spatial coherence of delta O-18(TR) records in the Amazon, this has not been tested. Furthermore, it is of interest to investigate whether other, possibly longer-lived, species similarly record interannual variation of Amazon precipitation, and can be used to develop climate sensitive isotope chronologies. In this study, we measured delta O-18 in tree rings from seven lowland and one highland tree species from Bolivia We found that cross-dating with delta O-18(TR) gave more accurate tree ring dates than using ring width. Our "isotope cross-dating approach" is confirmed with radiocarbon "bomb-peak" dates, and has the potential to greatly facilitate development of delta O-18(TR) records in the tropics, identify dating errors, and check annual ring formation in tropical trees. Six of the seven lowland species correlated significantly with C odorata, showing that variation in delta O-18(TR) has a coherent imprint across very different species, most likely arising from a dominant influence of source water delta O-18 on delta O-18(TR), In addition we show that delta O-18(TR) series cohere over large distances, within and between species. Comparison of two C. odorata delta O-18(TR) chronologies from sites several hundreds of kilometres apart showed a very strong correlation (r = 0.80, p < 0.001, 1901-2001), and a significant (but weaker) relationship was found between lowland C odorata trees and a Polylepis tarapacana tree growing in the distant Altiplano (r = 0.39, p < 0.01, 1931-2001). This large-scale coherence of delta O-18(TR) records is probably triggered by a strong spatial coherence in precipitation delta O-18 due to large-scale controls. These results highlight the strength of delta O-18(TR) as a precipitation proxy, and open the way for temporal and spatial expansion of precipitation reconstructions in South America. (C) 2015 The Authors. Published by Elsevier B.V.