Ecological and hydroclimate responses to strengthening of the Hadley circulation in South America during the Late Miocene cooling
Ecological and hydroclimate responses to strengthening of the Hadley circulation in South America during the Late Miocene cooling
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DOI：
10.1073/pnas.1810721116
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发表时间：
2019-05-14
影响因子：
11.1
通讯作者：
Feng, Ran
中科院分区：
文献类型：
--
作者：
Carrapa, Barbara;Clementz, Mark;Feng, Ran
近现代生态系统的建立是中新世晚期快速生态适应和气候变化的结果。在陆地上，随着包括C-4草原生态系统在内的开放生境的扩大，晚中新世干旱也在蔓延。安第斯山脉中部跨越晚中新世冷却的替代记录表明，南美洲在15-35度S之间发生了亚热带生态系统和水文气候的重组。保存在新近纪盆地中的陆源碳酸盐记录了三角洲O-18和C-13值从晚中新世冷却前到晚中新世冷却后的普遍增加，最强劲的发生在亚热带(S 25-30度)，这表明干旱和向以C4植物为主的生态系统的转变。这些变化与哈德利环流的加强和副热带向热带辐合区的水汽辐散密切相关，气候模式模拟的指定海面温度(SST)反映了不同程度的LMC赤道-顶极温度梯度变陡和CO_2下降。
Near-modern ecosystems were established as a result of rapid ecological adaptation and climate change in the Late Miocene. On land, Late Miocene aridification spread in tandem with expansion of open habitats including C-4 grassland ecosystems. Proxy records for the central Andes spanning the Late Miocene cooling (LMC) show the reorganization of subtropical ecosystems and hydroclimate in South America between 15 and 35 degrees S. Continental pedogenic carbonates preserved in Neogene basins record a general increase of delta O-18 and delta C-13 values from pre-LMC to post-LMC, most robustly occurring in the subtropics (25 to 30 degrees S), suggesting aridification and a shift toward a more C4-plant-dominated ecosystem. These changes are closely tied to the enhancement of the Hadley circulation and moisture divergence away from the subtropics toward the Intertropical Convergence Zone as revealed by climate model simulations with prescribed sea-surface temperatures (SSTs) reflecting different magnitudes of LMC steepening of equator-topole temperature gradient and CO2 decline.