Analysis of the Present State of Eutrophication of Lake Baikal

我们调查了俄罗斯贝加尔湖富营养化的现状。使用考察船进行的实地调查是与俄罗斯阿卡迪米科学学院湖泊研究所的俄罗斯研究人员一起进行的。虽然这些调查是综合的，但我们在以下几个方面综合了结果。1)浮游带浮游植物发育分析。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)滨海地带水生杂草的营养生理。5)营养离子对浮游植物生产过程的影响。6)从流域到远洋带的物质循环分析。7)滨海带湖水上涌过程的机理。8)分析了水温和水下光气候的分布和变化。我们证明了在贝加尔湖远洋带的广大区域，在热盐化期间，由微囊藻形成的大量水华是常见的现象。这种水华导致了有机质产量的增加。我们还明确了浮游生物群落内部的相互作用，特别是与营养元素动态有关的相互作用。作为贝加尔湖富营养化过程的基础，有机和无机物质的流向可以从流域确定，通过滨海带进入湖泊上层生物。研究结果将为今后贝加尔湖地区环境保护规划的制定提供参考。

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.