The system of biological production and ecological change in the huge lake promoted by the process of material loading and circulation of Lake Baikal

通过2002年至2005年4年的研究，我们取得了以下科学成果：研究了巴尔古津湾和利斯特维扬卡近海地区沉降通量的组成和季节变化。从冰封期到解冻期，活跃的生物生产使通量显著增加。研究了尿素的生物地球化学动力学。夏季尿素在地表水中的停留时间为3 ~ 6 d，冬季停留时间为560 d。考察了浮游植物的水平和垂直分布、营养状况、生产限制因子。巴尔古津湾近海浮游生物丰度呈上升趋势，但不受磷限制。对浮游植物初级生产中的营养限制进行了研究。在贝加尔湖的南部和中部，人们认为夏季首要的限制养分是磷而不是氮。用傅里叶变换和多离子回旋共振质谱法对溶解有机物进行了表征。异位腐殖质物质已被阐明在未变性的情况下被带到近海地区。该地区还产生了有机硫化合物等原生有机质。研究了水草对磷的吸收和积累机制。贝加尔湖和比洼湖的Elodea和Egeria机制无显著差异。研究了南海盆沿岸地区直立作物和附着藻群落的光合生产。尤以乌刺草和垂藻为优势群落，生物量较高。在近岸浅滩的岩石上发育的藻席显示出非常高的总光合作用速率。测定了巴尔古津湾的细菌、浮游植物和原生生物的垂直和水平丰度。在近海，叶绿素a的浓度与滤食性纤毛虫或捕虫纤毛虫的密度之间存在显著的相关性。对巴尔古津湾浮游植物的丰度、生长和放牧损失率进行了调查。浮游植物微生物食物网的丰度、组成和生态作用在近岸区和近海区存在差异。2004年6月至10月进行了长时间的水温调查。夏季，中部盆地和南部盆地西海岸表层气温同时下降，温差为10℃。建议发生深湖水上涌。少

We have got the following scientific results by our research for 4 years from 2002 to 2005.1. Composition and seasonal change of settling flux were examined in Barguzin Bay and off-shore area of Listvyanka. Significant increase of the flux by active biological production was observed from ice-covered to thawing periods of the lake.2. Bio-geochemical dynamics of urea was studied. Residence time of urea in the surface water was 3-6 days in summer, but was very long and 560 days in winter.3. Horizontal and vertical distributions, trophic state, production limiting factor of picophytoplankton was examined. Abundance of the plankton increased in off-shore area of Barguzin Bay, but was not under phosphorus limitation.4. Nutrient limitation in the primary production of phytoplankton was studied. In the southern and central Lake Baikal, the first limiting nutrient was thought to be phosphorus rather than nitrogen during summer.5. Dissolved organic matter was characterized with Fourier transfor … More m ion cyclotron resonance mass spectrometry. Alloctonus humic substances were elucidated to be brought to off-shore areas without denaturalization. Autochtonus organic matter, such as organic sulfur compounds, were produced in the area.6. Phosphate uptake and accumulation mechanisms of water plant were studied. Significant difference was not shown between their mechanisms of Elodea and Egeria in Lakes Baikal and Biwa.7. Standing crop and photosynthetic production of attached algal communities were studied at the littoral zone of the southern basin. High biomass were recorded especially in Ullothrix and Drapanaldiopsis dominated communities. The algal mat of Ullothrix developed on rocks on shallow near shore sites showed very high rate of gross photosynthesis.8. Vertical and horizontal abundance of bacteria, phytoplankton and protists were examined in Barguzin Bay. In off-shore, significant correlations were detected between concentrations of chlorophyll a and density of a filter feeding or raptorial ciliates.9. The abundance, growth and grazing loss rates of picophytoplankton were investigated in Barguzin Bay. There was a difference in the abundance, composition and ecological role in the microbial food web of picophytoplankton between the near-shore and the off-shore areas.10. Long time survey of water temperature was performed from June to October in 2004. Temperature decrease with 10℃ difference was observed at the same time in the surface layers on the western coasts of the central and southern basins in summer. Up-welling of deep lake water was suggested to occur. Less