Differential resilience of ancient sister lakes Ohrid and Prespa to environmental disturbances during the Late Pleistocene
Differential resilience of ancient sister lakes Ohrid and Prespa to environmental disturbances during the Late Pleistocene
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DOI：
10.5194/bg-13-1149-2016
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发表时间：
2016-01-01
期刊：
影响因子：
4.9
通讯作者：
Wilke, Thomas
中科院分区：
文献类型：
--
作者：
Jovanovska, Elena;Cvetkoska, Aleksandra;Wilke, Thomas
巴尔干半岛的奥赫里德湖和普雷斯帕湖等古代湖泊已成为研究地质和生物进化之间联系的模型系统。最近，启动了科学深钻项目“奥赫里德湖过去物种形成条件的科学合作”（SCOP-SCO），以更好地了解该湖的环境、气候和湖泊学演化。报告显示，奥赫里德湖在大约2000年期间经历了多次环境干扰。已有200万年的悠久历史。这些扰动包括持续较长时间的扰动（“新闻事件”），例如冰期-间冰期循环和海因里希事件，以及突然和短暂的扰动（“脉冲事件”），例如滑坡沉积、地震和火山灰沉积。后者包括更新世晚期最严重的火山爆发之一：Campanian Ignimbrite（称为 Y-5 海洋火山灰层）从 Campi Flegrei 火山口喷发，可追溯到 39.6+/-0.100 年前。该事件由大约的沉积物记录。奥赫里德湖 (DEEP-5045-1) 和普雷斯帕湖 (Co1204) 沉积岩芯中 15 厘米厚的火山灰层。巧合的是，这次脉冲事件与40.4-38400年前的海因里希H4事件叠加。在本文中，使用硅藻作为代理来比较这些湖泊对 Y-5（脉冲）和 H4（压力）干扰的响应。基于地层约束增量平方和聚类 (CONISS) 和无约束围绕中心点划分 (PAM) 分析，我们发现几乎没有证据表明两个湖中的硅藻群落组成对 H4 事件有响应。然而，Y-5 的流入引起了硅藻群落明显而快速的变化。在最初的响应之后，奥赫里德湖以及普雷斯帕湖（较小程度上）的群落组成慢慢恢复到准干扰前的状态。此外，没有证据表明与干扰有关的灭绝事件。这些发现的综合证据表明，奥赫里德湖和普雷斯帕湖可能没有经历政权更迭。因此得出的结论是，这两个湖泊都表现出对环境干扰的恢复能力。然而，奥赫里德湖似乎比普雷斯帕湖更具恢复力，因为硅藻群落的恢复更加明显，预计恢复时间仅为约 10 分钟。 1100 年 vs. 约 1100 年普雷斯帕湖已有 4000 年历史。差异响应的原因在很大程度上仍不清楚，但地质、湖泊年龄、湖沼学和硅藻代理的内在参数的差异可能发挥重要作用。
Ancient lakes, such as lakes Ohrid and Prespa on the Balkan Peninsula, have become model systems for studying the link between geological and biotic evolution. Recently, the scientific deep-drilling project Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOP-SCO) was initiated to better understand the environmental, climatic, and limnological evolution of the lake. It revealed that Lake Ohrid experienced a number of environmental disturbances during its ca. 2.0 million year long history. These are comprised of disturbances that lasted over longer periods of time ("press events") such as glacial-interglacial cycles and Heinrich events, as well as sudden and short disturbances ("pulse events") like the deposition of landslides, earthquakes, and volcanic ash depositions. The latter includes one of the most severe volcanic episodes during the Late Pleistocene: the eruption of the Campanian Ignimbrite (known as Y-5 marine tephra layer) from the Campi Flegrei caldera, dated to 39.6 +/- 0.1 thousand years ago. The event is recorded by the deposition of a ca. 15 cm thick tephra layer in sediment cores of lakes Ohrid (DEEP-5045-1) and Prespa (Co1204). Coincidently, this pulse event is superimposed by the Heinrich H4 event, 40.4-38.4 thousand years ago. In the current paper, diatoms were used as proxies to compare the responses of these lakes to the Y-5 (pulse) and the H4 (press) disturbances. Based on stratigraphically constrained incremental sum of squares cluster (CONISS) and unconstrained Partitioning Around Medoids (PAM) analyses, we found little evidence that diatom community compositions in either lake responded to the H4 event. However, the Y-5 influx caused clear and rapid diatom community changes. After the initial response, community compositions in Lake Ohrid and, to a lesser extent, in Lake Prespa slowly returned to their quasi pre-disturbance state. Moreover, there is no evidence for disturbance-related extinction events. The combined evidence from these findings suggests that lakes Ohrid and Prespa likely did not experience regime shifts. It is therefore concluded that both lakes show resilience to environmental disturbance. However, it seems that Lake Ohrid is more resilient than Lake Prespa, as the recovery of diatom communities is more pronounced and its estimated recovery time is only ca. 1100 years vs. ca. 4000 years in Lake Prespa. The reasons for the differential responses remain largely unknown, but differences in geology, lake age, limnology, and intrinsic parameters of the diatom proxies may play an important role.