Northern Mediterranean climate since the Middle Pleistocene: a 637 ka stable isotope record from Lake Ohrid (Albania/Macedonia)
Northern Mediterranean climate since the Middle Pleistocene: a 637 ka stable isotope record from Lake Ohrid (Albania/Macedonia)
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DOI：
10.5194/bg-13-1801-2016
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发表时间：
2016-01-01
期刊：
影响因子：
4.9
通讯作者：
Wagner, Bernd
中科院分区：
文献类型：
--
作者：
Lacey, Jack H.;Leng, Melanie J.;Wagner, Bernd
奥赫里德湖(马其顿/阿尔巴尼亚)是一个古老的湖泊，具有独特的生物多样性，对于研究气候、地质和构造事件对特有种群产生的影响具有全球意义。在这里，我们介绍了在奥赫里德湖过去物种形成条件科学合作(SCOP-SCO)项目中发现的复合岩心剖面上243米碳酸盐的氧(O-18)和碳(O-13)同位素数据。所调查的沉积物序列覆盖了过去约637ka。以前对该湖短岩心(长达15米，140 ka)的研究表明，沉积物的总无机碳(TIC)含量对上一次冰期-间冰期循环中的气候变化高度敏感。与暖期相对应的沉积物中含有丰富的内生方解石；然而，冰川沉积物中总体较低的TIC含量被早期成岩自生菱铁矿的离散条带所打断。内生方解石(三角洲O-18(C)和三角洲C-13(C))的同位素测量显示，间冰期之间和之间的变化表明，该湖在轨道和千年时间尺度上受到了古环境变化的影响。我们还测定了自生菱铁矿(S三角洲)和C-13三角洲(S)的同位素比值，并根据方解石和菱铁矿的氧同位素组成重建了637ka以来湖水的O-18三角洲(O-18三角洲(LW))。与冰期相比，间冰期的增量O-18(LW)值更高，这很可能是由于蒸发、夏季温度、冬季降水(降雪)的比例以及邻近的普雷斯帕湖的流入发生了变化。同位素地层学表明，奥赫里德湖经历了从海洋同位素阶段(MIS15)到MIS13的总体稳定期，突出了MIS14是一条特别温暖的冰川。在管理信息系统11和管理信息系统9期间，气候条件逐渐变得潮湿。管理信息系统9之后的间冰期的特点是，管理信息系统7、管理信息系统5和全新世的间冰期的条件越来越蒸发和干燥。我们的结果为地中海北部地区的长期气候变化提供了新的证据，这将为更好地了解重大环境事件对奥赫里德湖内生物进化的影响奠定基础。
Lake Ohrid (Macedonia/Albania) is an ancient lake with unique biodiversity and a site of global significance for investigating the influence of climate, geological, and tectonic events on the generation of endemic populations. Here, we present oxygen (delta O-18) and carbon (delta O-13) isotope data from carbonate over the upper 243 m of a composite core profile recovered as part of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOP-SCO) project. The investigated sediment succession covers the past ca. 637 ka. Previous studies on short cores from the lake (up to 15 m, < 140 ka) have indicated the total inorganic carbon (TIC) content of sediments to be highly sensitive to climate change over the last glacial-interglacial cycle. Sediments corresponding to warmer periods contain abundant endogenic calcite; however, an overall low TIC content in glacial sediments is punctuated by discrete bands of early diagenetic authigenic siderite. Isotope measurements on endogenic calcite (delta O-18(c) and delta C-13(c) ) reveal variations both between and within interglacials that suggest the lake has been subject to palaeoenvironmental change on orbital and millennial timescales. We also measured isotope ratios from authigenic siderite (delta O-18(s) and delta C-13(s)) and, with the oxygen isotope composition of calcite and siderite, reconstruct delta O-18 of lake water (delta O-18(lw)) over the last 637 ka. Interglacials have higher delta O-18(lw) values when compared to glacial periods most likely due to changes in evaporation, summer temperature, the proportion of winter precipitation (snowfall), and inflow from adjacent Lake Prespa. The isotope stratigraphy suggests Lake Ohrid experienced a period of general stability from marine isotope stage (MIS) 15 to MIS 13, highlighting MIS 14 as a particularly warm glacial. Climate conditions became progressively wetter during MIS 11 and MIS 9. Interglacial periods after MIS 9 are characterised by increasingly evaporated and drier conditions through MIS 7, MIS 5, and the Holocene. Our results provide new evidence for long-term climate change in the northern Mediterranean region, which will form the basis to better understand the influence of major environmental events on biological evolution within Lake Ohrid.