| 摘要: |
| 为了进一步探索重富营养化湖泊水质形成机理，1996年7月19日－9月2日，在太湖北端湖湾重富营养化水体—五里湖中层水体进行了试验。通过对微分方程的积分与数理统计分析，确定了该湖区该时段平均沉降通量为405g/(dm)，其中有机质沉降通量是无机沉降通量的3倍，有机质初始分解率为0.01251/h，长期分解率为 0.00662/h，1个月的时间就有80%的有机质分解掉。这种作用造成许多重富营养化湖泊，当悬浮物以死亡的藻类为主时，就会出现透明度低而叶绿素并不高的现象；藻类死亡后，逐步沉降并矿化分解，其残体与矿化物又可返回水体，其中的营养盐又被新生的藻类再次吸收利用，导致富营养化湖泊水质的变化长期处于恶性循环，这一现象在当前富营养化湖泊的治理中应予重视。 |
| 关键词: 沉降通量 有机质分解率 太湖 五里湖 |
| DOI：10.11693/hyhz200003015015 |
| 分类号: |
| 基金项目:中国国家科委和欧洲联盟科技部资助项目，C11＊－CT93－0094（DG12HSMU） |
附件 |
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| DOWWARD FLUX OF SUSPENDED SUBSTANCE AND ORGANIC DECOMPOSITION RATE IN WULIHU BAY, TAIHU LAKE |
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HU Chun-hua, PU Pei-min
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Nanjing Institute of Geography and Limnology, The Chinese Academy Of Sciences, Nanjing210008
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| Abstract: |
| In order to explore further the water-quality-change mechanism in hypertrophic lakes, the test was undertaken for the middle water layer in hypertrophic Wulihu Bay, northern Taihu Lake, during the period from July 19 to September 2 in 1996. On the basis of differential-equation integration calculus and mathematical and physical statistics, it was found that in this part of the lake during the period, the downward flux was 405 g/(dm2) on average, and that the downward organic fluxes were three times more than the downward inorganic fluxes. The initial decomposition rate of organic substances is about 0.01251/h, and the long-term decomposition rate is 0.00662/h, the instantaneous decomposition rate (D, h-1) may be described by the following equation; D=0.0066241+0.005859e-0.0066241t, where t is time (h). Around 80% of the organic substance was decomposed within a mouth. In many hypertrophic lakes it appears that transparency is low and chlorophyll-a is not high when suspended substances are dominated by dead algae. After algae die, they drop progressively, mineralize and are decomposed simultaneously, then the remains and mineralized substances return to water body, and the nutrients are absorbed and utilized by the newborn algae. Thus, the water quality changes are for long periods in vicious circles in the hypertrophic lake. The effects of rinsing and dredging etc., which cannot break the vicious circle, are not very ideal. The phenomenon should be taken into account during harnessing the present hypentrophic lake. |
| Key words: Downward flux of suspended substance, Organic decomposition rate, Taihu Lake, Wulihu Bay |
