Faculty of Oceanography and Geography, University of Gdansk, Gdansk, Poland.
Institute of Geography & Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland.
Sci Total Environ. 2022 Oct 10;842:156787. doi: 10.1016/j.scitotenv.2022.156787. Epub 2022 Jun 22.
Despite varved sediments being widely used for paleolimnological studies, little information is available about how climate and meteorological signals are recorded in varves at sub-seasonal to annual scale. We investigate links between meteorological and limnological conditions and their influence on biochemical varve formation and preservation of sub-seasonal climate signals in the sediments. Our study site is postglacial Lake Żabińskie located in NE Poland, in which thick and complex varved sediments have been studied for the last decade. These sediments provide an excellent material for studying the influence of short-term weather conditions on geological records. For this, we use an almost decade-long (2012-2019) series of observational data (meteorological conditions, physicochemical water parameters, and modern sedimentation observations) to understand varve formation processes. Then we compare these results with a high-resolution biogeochemical proxy dataset based on μXRF and hyperspectral imaging (HSI) measurements of a varved sediment core spanning the same period. Here we show direct links between the meteorological and limnological conditions and varve formation processes. This is particularly the case for air temperature which governs calcite laminae formation and primary production. We further show that calcite grain size is influenced by lake mixing intensity resulting from the wind activity, and that holomixis events lead to the formation of distinct manganese (Mn) peaks in the typically anoxic sediments. Our findings show that high-resolution non-destructive spectroscopy methods applied to complex biochemical varves, in combination with long observational limnological datasets, provide useful information for tracking meteorological and limnological processes in the past.
尽管纹层沉积物被广泛用于古湖泊学研究，但关于气候和气象信号如何在亚季节性到年度尺度上记录在纹层中，信息却很少。我们研究了气象和湖泊条件之间的联系，以及它们对生化纹层形成和保存亚季节性气候信号的影响。我们的研究地点是位于波兰东北部的后冰川期扎比辛斯基湖，过去十年一直在研究那里厚厚的、复杂的纹层沉积物。这些沉积物为研究短期天气条件对地质记录的影响提供了极好的材料。为此，我们使用了近十年（2012-2019 年）的观测数据系列（气象条件、理化水参数和现代沉积观测）来了解纹层形成过程。然后，我们将这些结果与一个高分辨率的生物地球化学示踪数据集进行比较，该数据集基于微 XRF 和高光谱成像（HSI）对同一时期的纹层沉积物芯的测量结果。在这里，我们展示了气象和湖泊条件与纹层形成过程之间的直接联系。特别是气温，它控制着方解石纹层的形成和初级生产力。我们进一步表明，碳酸钙晶粒尺寸受到风活动引起的湖泊混合强度的影响，而全混事件导致在典型缺氧沉积物中形成明显的锰（Mn）峰值。我们的研究结果表明，应用于复杂生化纹层的高分辨率非破坏性光谱方法与长期观测到的湖泊学数据集相结合，可以为追踪过去的气象和湖泊学过程提供有用的信息。
