Analysis of the Present State of Eutrophication of Lake Baikal

对俄罗斯贝加尔湖富营养化现状进行了调查。实地调查由俄罗斯科学院湖沼研究所的俄罗斯研究人员使用研究船进行。虽然这些调查是综合调查，但我们综合了以下几个方面的结果。1)远洋区浮游植物发育分析。2)微生物群落分布及其在湖泊物质循环中的作用。3)滨海-远洋过渡带营养元素的分布。4)沿岸水草的营养生理。5)营养离子对浮游植物生产过程的影响。6)流域至远洋带物质循环分析。7)湖滨带湖水上涌机理。8)水温和水下光气候的分布和变化分析。研究结果表明，在贝加尔湖热星化时期，碧青杆菌形成广泛的水华是贝加尔湖中上层广阔地区的普遍现象。这种水华导致有机质产量增加。我们还明确了浮游生物群落内部的相互作用，特别是营养元素的动态。作为贝加尔湖富营养化过程的基础，有机和无机物质的流动可以确定从小流域经沿岸带向湖泊上层水体的流动。研究结果可为今后贝加尔湖地区的环境保护规划提供参考。

We investigated the present state of eutrophication of Lake Baikal, Russia. The field surveys using research vessels were conducted with the Russian researchers from The Limnological Institute, Russian Akademy of Science. Although these surveys were integrated ones, we synthesized the results in the following aspects. 1) Analysis of phytoplankton development at the pelagic zone. 2) Distribution of microbial community and its role in lake matter cycles. 3) Distribution of nutrient elements in the littoral-pelagic transient zone. 4) Nutrient physiology of aquatic weeds at the littoral zone. 5) Effects on nutrient ions on the phytoplankton production process. 6) Analysis of matter cycle from the watershed to the pelagic zone. 7) Mechanism of the upwelling process of the lake water at the littoral zone. 8) Analysis of the distribution and the variation of water temperature and underwater light climate. We demonstrated that extensive bloom formation by picocyanobacteria is common phenomena in the broad area of the pelagic zone of L. Baikal during the thermal staratification period. This bloom resulted in the increased organic matter production. We also made clear the interactions within the plankton community, especially with reference to nutrient elements dynamics. As the basis of the eutrophication process in L. Baikal, the flow of organic and inorganic materials could be determined from, the watershed to the lake pelagics via littoral zone. The results of the present study would be useful in making plan for environmental conservation of the Baikal region in future.