Lipid Biomarker Record Documents Hydroclimatic Variability of the Mississippi River Basin During the Common Era
Lipid Biomarker Record Documents Hydroclimatic Variability of the Mississippi River Basin During the Common Era
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DOI：
10.1029/2020gl087237
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发表时间：
2020-06-28
影响因子：
5.2
通讯作者：
Tierney, Jessica E.
中科院分区：
文献类型：
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作者：
Munoz, Samuel E.;Porter, Trevor J.;Tierney, Jessica E.
密西西比河流域的洪水和干旱是造成严重经济破坏的常年危害。在这里，我们开发并分析了马蹄湖（美国伊利诺伊州）的一种新的脂质生物标志物记录，以评估与过去1,800年来该地区发生的水文气候极端事件相关的气候条件。我们提出了地球化学代理证据的温度和湿度的变化，使用支链甘油二烷基甘油四醚（brGDGT）和植物叶蜡氢同位素组成（δ H-2（蜡）），并使用同位素启用耦合模型模拟诊断控制这些代理。我们的数据显示，中世纪时期（公元1000- 1600年）的明显变暖与中部大陆的特大干旱相对应。密西西比河上游流域的严重洪水也发生在中世纪时期，与暖季湿度增加的时期相对应。我们的研究结果意味着，预计温度和暖季降水的增加可能会增加干旱和洪水的危险，在这个经济上至关重要的region.Plain语言摘要密西西比河流域是一个经济上至关重要的地区，工业和农业，但它很容易破坏性的洪水和干旱。在这里，我们使用保存在湖泊沉积物核心中的有机分子来重建过去1,800年的温度和季节性湿度模式。我们的重建表明，中世纪时期（约。1000- 1，600年）相对温暖，该地区气温升高与严重干旱和洪水频率增加有关。这些发现普遍支持气候模式预测的干旱和洪水灾害增加的密西西比河流域的人为气候变化的结果。
Floods and droughts in the Mississippi River basin are perennial hazards that cause severe economic disruption. Here we develop and analyze a new lipid biomarker record from Horseshoe Lake (Illinois, USA) to evaluate the climatic conditions associated with hydroclimatic extremes that occurred in this region over the last 1,800 years. We present geochemical proxy evidence of temperature and moisture variability using branched glycerol dialkyl glycerol tetraethers (brGDGTs) and plant leaf wax hydrogen isotopic composition (delta H-2(wax)) and use isotope-enabled coupled model simulations to diagnose the controls on these proxies. Our data show pronounced warming during the Medieval era (CE 1000-1,600) that corresponds to midcontinental megadroughts. Severe floods on the upper Mississippi River basin also occurred during the Medieval era and correspond to periods of enhanced warm-season moisture. Our findings imply that projected increases in temperature and warm-season precipitation could enhance both drought and flood hazards in this economically vital region.Plain Language Summary The Mississippi River basin is an economically vital region for industry and agriculture, but it is prone to disruptive flooding and drought. Here we use organic molecules preserved in a lake sediment core to reconstruct the temperature and seasonal moisture patterns of the last 1,800 years. Our reconstruction shows that the Medieval period (ca. CE 1000-1,600) was relatively warm and that warmer temperatures in this region are associated with increased frequencies of severe droughts and floods. These findings generally support climate model projections of increasing drought and flood hazard in the Mississippi River basin as a result of anthropogenic climate change.