Hydrology plays a dominant role in wetland plant distribution and microbial composition, but few studies explicitly attempted to relate the linkage between wetland vegetation and microbial community. The present study...Hydrology plays a dominant role in wetland plant distribution and microbial composition, but few studies explicitly attempted to relate the linkage between wetland vegetation and microbial community. The present study consisted of five wetland plant communities along three adjacent flood gradients zones(zone 1 dominated by Carex appendiculat, zone 2 dominated by Eleocharis ovate, and zone 3 dominated by Phragmites australis/Bidens pilosa/Calamagrostis angustifolia, which formed separate, monoculture patches). Gram negative and arbuscular mycorrhizal fungal phospholipid fatty acid(PLFA) are more abundant in the site with short flooding period(zone 3) than in the site with long flooding period(zone 1), and they are also different in the P. australis, B. spilosa and C. angustifolia of zone 3. Principle Component Analysis(PCA) showed that the flooding period could explain 92.4% of variance in microbial composition. Redundancy Analysis(RDA) showed that available nitrogen(AN), total nitrogen(TN) and soil organic matter(SOM) could explain the 79.5% of variance in microbial composition among E. ovata, P. australis, B. pilosa and C. angustifolia. Results demonstrated that flooding period was the main factor in driving the microbial composition and plant-derived resources could influence soil microbial composition in the seasonally flooded zones.展开更多
The Nokoue Lake is the largest lake of Benin Republic and it is also considered as one of the most productive lagoon ecosystems in West Africa. This productivity is decreasing and thus raises productivity issue for a ...The Nokoue Lake is the largest lake of Benin Republic and it is also considered as one of the most productive lagoon ecosystems in West Africa. This productivity is decreasing and thus raises productivity issue for a better management and conservation. Macroinvertebrate can be useful for this purpose. A study was conducted to assess the spatial variation of macroinvertebrates during high flood period. A total of 3892 macroinvertebrates of fresh and brackish water were sampled during the survey. Structural analysis of the macroinvertebrate community revealed that it was made up of 16 orders, 48 families and 66 genera dominated by Insecta compared to Mollusca, Crustacea and the Annelida. Insects were dominated by Diptera (Chironomus sp. and Tanytarsus sp.), Coleoptera (Dystiscidae) and accounted for 57.1% of the sampled population. Mollusca, Crustacea, Annelida and Arachnida were the following most abundant and represented 23.9%, 10.7%, 8.1% and 0.2% of the total population, respectively. The Evenness index of Pielou was higher on the Station 8 (0.91 - 0.97), close to Oueme River. However, no significant difference (p > 0.05) was observed neither between station nor between month on the Shannon-Wiener index (2.06 - 4.31), Simpson index (0.04 - 0.40) and the taxa number (10 - 27). Macroinvertebrate assemblages and composition were primarily due to changes in water quality dependent on hydroclimatic changes and probably to anthropogenic actions. This suggests the need for real investigation of the macroinvertebrate biological capacity when formulating conservation strategies for the Nokoue Lake.展开更多
Documented materials, especially those about flooding catastrophe, are abundant comprehensive and well-preserved, which makes possible the systematical collection of materials about historical document about climate e...Documented materials, especially those about flooding catastrophe, are abundant comprehensive and well-preserved, which makes possible the systematical collection of materials about historical document about climate evolution in Changjiang (Yangtze) Delta region and its neighboring areas. We make good use of the exceptional information to discuss the genesis and principle of flooding in this region. Analysis shows that the main flooding periods in the studied region in the last 2000 years were the Western Jin Dynasty, Eastern Jin Dynasty, Northern and Southern Dynasties, Southern Song Dynasty, Yuan Dynasty, Ming Dynasty and Qing Dynasty. The periods with flooding peak values were the 4th century, 5th century, 7th century, 9th century, early 12th century, early 14th century, mid-15th century, and early 18th century A.D. Possibility of reappearance of flooding peak value in the early 21st century will be great, and the hazard prevention and the hazard reduction will be still hard.展开更多
A brief introduction of a global atmospheric circulation model CCM3, which is used to simulate the precipitation in China, the height and the flow fields of the atmosphere, is made and the reliability of simulation is...A brief introduction of a global atmospheric circulation model CCM3, which is used to simulate the precipitation in China, the height and the flow fields of the atmosphere, is made and the reliability of simulation is analyzed. According to the negative correlation between rainfall in the first flood period in South China (FFSC) and sea surface temperature anomalies (SSTA) in a key region in western Pacific warm pool (West Region), two sensitive experiments are designed to investigate the effects of the latter on the former and the possible physical mechanism is discussed. It is found that in cold water (warm water) years, the rainfall in South China (SC) is far more (less) than normal, while the rainfall in the middle and low reaches of the Yangtze River is relatively less (more). The best correlative area of precipitation is located in Guangdong Province. It matches the diagnostic result well. The effect of SSTA on precipitation of FFSC is realized through the abnormality of atmospheric circulation and tested by a P-σnine-layer regional climate model. Moreover, the simulated result of the P-σmodel is basically coincident with that of the CCM3.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.41361015,41271106,41271107,41501105)Open Fund of the State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration,Northeast Normal University(No.130028630)
文摘Hydrology plays a dominant role in wetland plant distribution and microbial composition, but few studies explicitly attempted to relate the linkage between wetland vegetation and microbial community. The present study consisted of five wetland plant communities along three adjacent flood gradients zones(zone 1 dominated by Carex appendiculat, zone 2 dominated by Eleocharis ovate, and zone 3 dominated by Phragmites australis/Bidens pilosa/Calamagrostis angustifolia, which formed separate, monoculture patches). Gram negative and arbuscular mycorrhizal fungal phospholipid fatty acid(PLFA) are more abundant in the site with short flooding period(zone 3) than in the site with long flooding period(zone 1), and they are also different in the P. australis, B. spilosa and C. angustifolia of zone 3. Principle Component Analysis(PCA) showed that the flooding period could explain 92.4% of variance in microbial composition. Redundancy Analysis(RDA) showed that available nitrogen(AN), total nitrogen(TN) and soil organic matter(SOM) could explain the 79.5% of variance in microbial composition among E. ovata, P. australis, B. pilosa and C. angustifolia. Results demonstrated that flooding period was the main factor in driving the microbial composition and plant-derived resources could influence soil microbial composition in the seasonally flooded zones.
文摘The Nokoue Lake is the largest lake of Benin Republic and it is also considered as one of the most productive lagoon ecosystems in West Africa. This productivity is decreasing and thus raises productivity issue for a better management and conservation. Macroinvertebrate can be useful for this purpose. A study was conducted to assess the spatial variation of macroinvertebrates during high flood period. A total of 3892 macroinvertebrates of fresh and brackish water were sampled during the survey. Structural analysis of the macroinvertebrate community revealed that it was made up of 16 orders, 48 families and 66 genera dominated by Insecta compared to Mollusca, Crustacea and the Annelida. Insects were dominated by Diptera (Chironomus sp. and Tanytarsus sp.), Coleoptera (Dystiscidae) and accounted for 57.1% of the sampled population. Mollusca, Crustacea, Annelida and Arachnida were the following most abundant and represented 23.9%, 10.7%, 8.1% and 0.2% of the total population, respectively. The Evenness index of Pielou was higher on the Station 8 (0.91 - 0.97), close to Oueme River. However, no significant difference (p > 0.05) was observed neither between station nor between month on the Shannon-Wiener index (2.06 - 4.31), Simpson index (0.04 - 0.40) and the taxa number (10 - 27). Macroinvertebrate assemblages and composition were primarily due to changes in water quality dependent on hydroclimatic changes and probably to anthropogenic actions. This suggests the need for real investigation of the macroinvertebrate biological capacity when formulating conservation strategies for the Nokoue Lake.
基金Under the auspices of the National Natural Science Foundation of China (No.40071083),"985 Project"for discipline construction
文摘Documented materials, especially those about flooding catastrophe, are abundant comprehensive and well-preserved, which makes possible the systematical collection of materials about historical document about climate evolution in Changjiang (Yangtze) Delta region and its neighboring areas. We make good use of the exceptional information to discuss the genesis and principle of flooding in this region. Analysis shows that the main flooding periods in the studied region in the last 2000 years were the Western Jin Dynasty, Eastern Jin Dynasty, Northern and Southern Dynasties, Southern Song Dynasty, Yuan Dynasty, Ming Dynasty and Qing Dynasty. The periods with flooding peak values were the 4th century, 5th century, 7th century, 9th century, early 12th century, early 14th century, mid-15th century, and early 18th century A.D. Possibility of reappearance of flooding peak value in the early 21st century will be great, and the hazard prevention and the hazard reduction will be still hard.
基金sponsored by the NSFC key project (40233037) and the "National Key Developing Programme for Basic Science" project (2004CB418300)
文摘A brief introduction of a global atmospheric circulation model CCM3, which is used to simulate the precipitation in China, the height and the flow fields of the atmosphere, is made and the reliability of simulation is analyzed. According to the negative correlation between rainfall in the first flood period in South China (FFSC) and sea surface temperature anomalies (SSTA) in a key region in western Pacific warm pool (West Region), two sensitive experiments are designed to investigate the effects of the latter on the former and the possible physical mechanism is discussed. It is found that in cold water (warm water) years, the rainfall in South China (SC) is far more (less) than normal, while the rainfall in the middle and low reaches of the Yangtze River is relatively less (more). The best correlative area of precipitation is located in Guangdong Province. It matches the diagnostic result well. The effect of SSTA on precipitation of FFSC is realized through the abnormality of atmospheric circulation and tested by a P-σnine-layer regional climate model. Moreover, the simulated result of the P-σmodel is basically coincident with that of the CCM3.