RAINFALLS ACCELERATE THE DECLINE PROCESS OF MICROCYSTIS (CYANOPHYCEAE) BLOOMS

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	RAINFALLS ACCELERATE THE DECLINE PROCESS OF MICROCYSTIS (CYANOPHYCEAE) BLOOMS
	Wang, Zhicong 1,2; Li, Dunhai 1; Li, Zhongjie 1
刊名	FRESENIUS ENVIRONMENTAL BULLETIN
	2012
卷号	21 期号:8A 页码:2145-2152
关键词	rainfall Microcystis bloom decline buoyancy particle size photosynthetic activity
ISSN号	1018-4619
通讯作者	Li, DH (reprint author), Chinese Acad Sci, Inst Hydrobiol, 7 Donghu S Rd, Wuhan 430072, Hubei Province, Peoples R China.
中文摘要	In Lake Chaohu, China, a vertical stratification of water temperature and dissolved oxygen (DO) was observed on sunny days, whereas it was not obvious on rainy days and DO was low in the whole water body. This indicates that rainfall can lead to a vertical convection and a low DO. In this study, we found that the density of small Microcystis colonies (<100 mu m) was higher on rainy day than on sunny days, implying that rainfall had a mechanical impact on large colonies and broke them into small colonies. The measured results of algae collected on sunny day showed that oxygen removal in mucilaginous envelope, mechanical damage, and destruction of gas vesicles could significantly decrease the buoyancy of Microcystis colonies by 27.36 +/- 4.85% (p < 0.01), 45.57 +/- 5.29% (p < 0.01) and 18.23 +/- 3.24% (p < 0.05) in one-way ANOVA, respectively. However, when algae sampled on rainy day were treated with above mentioned three methods, the buoyancy of Microcystis colonies only decreased by 6.72 +/- 2.77% (p > 0.05), 33.37 +/- 4.02% (p < 0.01), and 13.34 +/- 3.58% (p < 0.05) in one-way ANOVA, respectively. These results suggested the rapid decrease in colony buoyancy on rainy days was not only due to the breakage of colonies but also due to the loss of oxygen bubble entrapped in mucilaginous envelope. Under simulated rainy day condition, the low DO in the water significantly decreased the photosynthetic activity, the up-floating velocity, and the growth rate of Microcystis colonies, which suggested that low-oxygen in some areas of lake could damage the photo-system of Microcystis and cause a bloom decline. The reculture of settled Microcystis colonies collected on rainy days showed that the recovery of photosynthetic activity and growth rate were very low, suggesting that most of the settled colonies could not act as seed source for the next bloom even though they were stirred and suspended in the water column after the weather conditions became suitable. Therefore, the physiological inactivity and the settling of Microcystis colonies under frequent heavy rainfall condition are the important reasons for the seasonal, rapid, irreversible collapse of severe algal blooms until the following year.
英文摘要	In Lake Chaohu, China, a vertical stratification of water temperature and dissolved oxygen (DO) was observed on sunny days, whereas it was not obvious on rainy days and DO was low in the whole water body. This indicates that rainfall can lead to a vertical convection and a low DO. In this study, we found that the density of small Microcystis colonies (<100 mu m) was higher on rainy day than on sunny days, implying that rainfall had a mechanical impact on large colonies and broke them into small colonies. The measured results of algae collected on sunny day showed that oxygen removal in mucilaginous envelope, mechanical damage, and destruction of gas vesicles could significantly decrease the buoyancy of Microcystis colonies by 27.36 +/- 4.85% (p < 0.01), 45.57 +/- 5.29% (p < 0.01) and 18.23 +/- 3.24% (p < 0.05) in one-way ANOVA, respectively. However, when algae sampled on rainy day were treated with above mentioned three methods, the buoyancy of Microcystis colonies only decreased by 6.72 +/- 2.77% (p > 0.05), 33.37 +/- 4.02% (p < 0.01), and 13.34 +/- 3.58% (p < 0.05) in one-way ANOVA, respectively. These results suggested the rapid decrease in colony buoyancy on rainy days was not only due to the breakage of colonies but also due to the loss of oxygen bubble entrapped in mucilaginous envelope. Under simulated rainy day condition, the low DO in the water significantly decreased the photosynthetic activity, the up-floating velocity, and the growth rate of Microcystis colonies, which suggested that low-oxygen in some areas of lake could damage the photo-system of Microcystis and cause a bloom decline. The reculture of settled Microcystis colonies collected on rainy days showed that the recovery of photosynthetic activity and growth rate were very low, suggesting that most of the settled colonies could not act as seed source for the next bloom even though they were stirred and suspended in the water column after the weather conditions became suitable. Therefore, the physiological inactivity and the settling of Microcystis colonies under frequent heavy rainfall condition are the important reasons for the seasonal, rapid, irreversible collapse of severe algal blooms until the following year.
WOS标题词	Science & Technology ; Life Sciences & Biomedicine
类目[WOS]	Environmental Sciences
研究领域[WOS]	Environmental Sciences & Ecology
关键词[WOS]	CYANOBACTERIUM MICROCYSTIS ; CHLOROPHYLL FLUORESCENCE ; NITROGEN DYNAMICS ; PHOTOSYSTEM-II ; LAKE CHAOHU ; IN-VIVO ; CHINA ; AERUGINOSA ; SHALLOW ; DAMAGE
收录类别	SCI
资助信息	National Basic Research and Development Plan [2008CB418002]; National Major Programs of Water Body Pollution Control and Remediation [2009ZX07104-005]; National Natural Science Foundation of China [30830025]
语种	英语
WOS记录号	WOS:000309326100001
公开日期	2013-01-09
内容类型	期刊论文
源URL	[http://ir.ihb.ac.cn/handle/342005/17192]
专题	水生生物研究所_淡水生态学研究中心_期刊论文
作者单位	1.Chinese Acad Sci, Inst Hydrobiol, Wuhan 430072, Hubei Province, Peoples R China 2.Chinese Acad Sci, Grad Univ, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Wang, Zhicong,Li, Dunhai,Li, Zhongjie. RAINFALLS ACCELERATE THE DECLINE PROCESS OF MICROCYSTIS (CYANOPHYCEAE) BLOOMS[J]. FRESENIUS ENVIRONMENTAL BULLETIN,2012,21(8A):2145-2152.
APA	Wang, Zhicong,Li, Dunhai,&Li, Zhongjie.(2012).RAINFALLS ACCELERATE THE DECLINE PROCESS OF MICROCYSTIS (CYANOPHYCEAE) BLOOMS.FRESENIUS ENVIRONMENTAL BULLETIN,21(8A),2145-2152.
MLA	Wang, Zhicong,et al."RAINFALLS ACCELERATE THE DECLINE PROCESS OF MICROCYSTIS (CYANOPHYCEAE) BLOOMS".FRESENIUS ENVIRONMENTAL BULLETIN 21.8A(2012):2145-2152.