Abstract

Long-chain alkenones (LCAs)—lipides produced by some microalgae of the Haptophyta group in seas and continental water bodies—are promising paleomarkers of climate changes because they are well-preserved in bottom sediments. The hydrocarbon chain and the degree of unsaturation of double bonds of this class of lipides can vary depending on habitat conditions of their producers. For the first time, we have discovered LCAs in the bottom sediments of two saline meromictic lakes Shira and Uchum located in arid steppes of southern Siberia (the North Minusinsk Depression) and estimated the distribution of their total content, length, and the degree of unsaturation. The highly abundant population of producers of LCAs—haptophyte algae of the genus Isochrysis (Haptophyta)—is revealed in the water column of Lake Uchum. It is shown that the species composition of the haptophyte algae and composition of the LCAs in the lakes under study are similar to those in saline stratified lakes of North America (Saskatchewan, Canada) with a similar climate and salt composition. The abundance of the С37:4 alkenone in the bottom sediments in the last 100 years reflected the variations in lake salinity caused by the documented changes in the water level. In this way, it is shown that the LCAs may be used as a paleomarker of climate-driven changes in the water level of the saline lakes in southern Siberia.

中文翻译：

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北米尼辛斯克De陷（南西伯利亚）的盐湖湖泊中的长链烯酮：知识和可能与水位动力学的关系。

摘要

长链烯酮（LCA）-由七足类植物群的一些微藻在海洋和大陆水域中产生的脂质-是有希望的气候变化的古迹，因为它们在底部沉积物中保存完好。这类脂质的烃链和双键的不饱和度可以根据其生产者的生境条件而变化。我们首次在位于西伯利亚南部干旱草原（北米努辛斯克sk陷）的两个盐渍性虹彩湖Shira和Uchum的底部沉积物中发现了LCAs，并估计了其总含量，长度和不饱和度的分布。LCAS的生产者的数量非常丰富，即等鞭藻属的七生植物藻类（Haptophyta）-在Uchum湖的水柱中被发现。结果表明，所研究的湖泊中的触藻植物的藻类组成和LCAs的组成与北美（加拿大萨斯喀彻温省）的盐化分层湖泊中的气候和盐组成相似。在过去的100年中，底部沉积物中С37：4烯酮的丰度反映了有记录的水位变化引起的湖盐度变化。通过这种方式，表明LCA可以用作气候驱动的西伯利亚南部盐湖水位变化的古标志。