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首页> 美国卫生研究院文献>Philosophical Transactions of the Royal Society B: Biological Sciences >Diatom succession trends in recent sediments from Lake Baikal and their relation to atmospheric pollution and to climate change
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Diatom succession trends in recent sediments from Lake Baikal and their relation to atmospheric pollution and to climate change

机译：贝加尔湖最近沉积物中硅藻的继承趋势及其与大气污染和气候变化的关系

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Recent environmental change in Lake Baikal has been attributed to anthropogenic influences on the ecosystem, especially through pollution and cultural eutrophication. These hypotheses are tested in this paper principally by diatom analyses in 20 short sediment cores. Most of the cores were collected with a new type of box corer specifically designed for use on Lake Baikal. Most cores contain a good sediment record but turbidites occur in some sediment profiles which may be best recognized using a combination of techniques, such as radiometric dating and percentage dry weight analyses. The most recent sediments, especially those in the southern basin and in the very north of Baikal, contain a record of anthropogenic contamination in the form of lead and spheroidal carbonaceous particles, which confirms that the southern basin of Baikal is most affected by atmospheric sources of pollution. However, there is no sedimentary diatom evidence indicating offshore water quality deterioration in Baikal owing to air pollution or eutrophication. Small increases in diatoms which indicate nutrient enrichment (e.g. Stephanodiscus minutulus, Synedra acus v. radians and Synedra acus v. acus) may reflect local eutrophication of the shallow waters close to the Selenga Delta and certain coastal sites in the southern basin near to the Baikalsk paper and pulp mill. By using numerical techniques, Lake Baikal can be split into at least four regions on the basis of its surface sediment flora: the south, middle and north basins, and the shallow waters surrounding the Selenga Delta region. Diatom analyses reveal that the endemic flora of Lake Baikal has been constantly changing over at least the last 2000 years and that these fluctuations are probably responses to natural climatic variability. Recent sediments of Baikal may be affected by taphanomic processes (e.g. dissolution) and turbidite deposition, and these must be taken into account when interpreting the sedimentary diatom record. The diatom flora of the lake is currently dominated by several species, such as Aulacoseira baicalensis, A. islandica, Cyclotella minuta and Stephanodiscus binderanus v. baicalensis. All these species, except for C. minuta, have become more common in the lake in approximately the last 130 years, and we hypothesize that these changes may be attributed to a number of different processes linked to an ameliorating climate after the end of the Little Ice Age. The results presented here have important implications for this recently designated World Heritage Site, with regard to future pollution controls and catchment management policies.
机译：贝加尔湖最近的环境变化归因于人类活动对生态系统的影响，特别是通过污染和文化富营养化。本文主要通过对20个短沉积岩心中的硅藻分析对这些假设进行了检验。大多数岩心是使用专门为贝加尔湖设计的新型箱式挖矿机收集的。大多数岩心都具有良好的沉积物记录，但是在某些沉积物剖面中会出现混浊，这可以结合使用多种技术来最好地加以识别，例如放射性测年和干重百分比分析。最近的沉积物，尤其是贝加尔湖南部和北部最北部的沉积物，以铅和球状碳质颗粒的形式存在着人为污染的记录，这证明贝加尔湖南部盆地受大气中碳源的影响最大。污染。但是，没有沉积硅藻的证据表明由于空气污染或富营养化导致贝加尔湖的近岸水质恶化。硅藻的少量增加表明营养物质富集（例如Stephanodiscus minutulus，Synedra acus v。radians和Synedra acus v。acus）可能反映了Selenga Delta附近浅水区和贝加尔斯克附近南部盆地某些沿海地区的局部富营养化造纸厂。通过使用数值技术，贝加尔湖可以根据其表面沉积物菌群至少分为四个区域：南部，中部和北部盆地以及Selenga三角洲地区周围的浅水区。硅藻的分析表明，至少在过去的2000年中，贝加尔湖的特有植物群一直在不断变化，这些波动可能是对自然气候变化的反应。贝加尔湖最近的沉积物可能受过流过程（例如溶解）和浊石沉积的影响，在解释沉积硅藻记录时必须考虑这些因素。该湖的硅藻植物区系目前由几种物种控制，例如Aulacoseira baicalensis，A。islandica，Cyclotella minuta和Stephanodiscus bondanus v。baicalensis。在近130年来，除了C. minuta以外，所有这些物种在湖中都变得越来越普遍，我们假设这些变化可能归因于Little结束后与气候改善有关的许多不同过程。冰河世纪。就未来的污染控制和集水区管理政策而言，此处提出的结果对该新近指定的世界遗产具有重要意义。

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