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首页> 外文期刊>Journal of Paleolimnology >Diatom-inferred lake level from near-shore cores in a drainage lake from the Experimental Lakes Area, northwestern Ontario, Canada
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Diatom-inferred lake level from near-shore cores in a drainage lake from the Experimental Lakes Area, northwestern Ontario, Canada

机译：来自加拿大安大略省西北部实验湖区的排水湖中近岸岩心的硅藻推断湖平面

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We inferred late Holocene lake-level changes from a suite of near-shore gravity cores collected in Lake 239 (Rawson Lake), a headwater lake in the Experimental Lakes Area, northwestern Ontario. Results were reproduced across all cores. A gravity core from the deep central basin was very similar to the near-shore cores with respect to trends in the percent abundance of the dominant diatom taxon, Cylcotella stelligera. The central basin, however, does not provide a sensitive site for reconstruction of lake-level changes because of the insensitivity of the diatom model at very high percentages of C. stelligera and other planktonic taxa. Quantitative estimates of lake level are based on a diatom-inferred depth model that was developed from surficial sediments collected along several depth transects in Lake 239. The lake-level reconstructions during the past ~3,000 years indicate that lake depth varied on average by ±2 m from present-day conditions, with maximum rises of ~3–4 m and maximum declines of ~3.5–5 m. The diatom-inferred depth record indicates several periods of persistent low levels during the nineteenth century, from ~900 to 1100 AD, and for extended periods prior to ~1,500 years ago. Periods of inferred high lake levels occurred from ~500 to 900 AD and ~1100 to 1650 AD. Our findings suggest that near-shore sediments from small drainage lakes in humid climates can be used to assess long-term fluctuations in lake level and water availability.
机译：我们从安大略湖西北部实验湖区的上游水库239湖（罗森湖）收集的一组近岸重力岩心中推断出全新世晚期的湖面变化。结果在所有核心上均得到再现。就占优势的硅藻类群Cylcotella stelligera的丰度百分比趋势而言，深部中部盆地的重力岩心与近岸岩心非常相似。但是，由于硅藻模型在极高比例的C. stelligera和其他浮游生物群中不敏感，因此中部盆地没有为重建湖面变化提供敏感地点。湖泊水位的定量估算基于硅藻推断的深度模型，该模型是根据沿239个湖泊的几个深度样点收集的表层沉积物开发的。过去3,000年来的湖泊水位重建表明，湖泊深度平均变化了±2从目前的情况来看，最大距离为m，最大上升约3-4 m，最大下降约3.5-5 m。硅藻推断的深度记录表明，在19世纪（从公元900到1100年）以及在大约1500年前的较长时期中，有几个持续的低水平时期。推断的高湖水位发生于公元500〜900年和公元1100〜1650年。我们的研究结果表明，潮湿气候下的小型排水湖泊的近岸沉积物可用于评估湖泊水位和水的长期波动。

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