Northeast China is the region with the largest area of wetlands in China. The Sanjiang Plain and the Songnen Plain are large freshwater marsh distribution regions that are affected by climate warming and by the increa...Northeast China is the region with the largest area of wetlands in China. The Sanjiang Plain and the Songnen Plain are large freshwater marsh distribution regions that are affected by climate warming and by the increasing frequency and density of extreme weather and are the regions most subject to disturbances by human activities in Northeast China. The wetlands of the Sanjiang Plain and the Songnen Plain have shrunk severely in the past 60 years, and wetland functions have been reduced substantially because of climate change, unreasonable land use, fire episodes, engineering and construction works and urbanization. Large-scale agricultural development started in the 1950 s has been the most important driving factor for wetland loss and degradation in the Sanjiang Plain. Water shortage has been the most important factor for degradation and fragmentation of wetlands in the Songnen Plain. To mitigate wetland degradation and better protect wetlands, special regulations, long-term mechanisms and technical support of wetland protection should be established. A wetland compensation program should be implemented, and technologies for increasing the adaptive capacity of wetlands should be developed. Moreover, it is most important to find the balanced threshold between agricultural development and wetland protection.展开更多
The distribution of iron monosulfide (quantified as acid volatile sulfur: SAV) was compared with geo- chemical properties that are known to affect its formation and accumulation in three coastal Holocene acid sulfate ...The distribution of iron monosulfide (quantified as acid volatile sulfur: SAV) was compared with geo- chemical properties that are known to affect its formation and accumulation in three coastal Holocene acid sulfate soils (ASS) at Tuckean Swamp, McLeods Creek and Bungawalbyn Swamp respectively. These properties included PH, reactive iron (FeR), pore-water sulfate (SO:42-) and organic carbon (OC). Iron monosulfide was concentrated at the oxic/anoxic boundary. The Tuckean Swamp and McLeods Creek sites are Holocene sediments, whereas the Bungawalbyn Swamp is a Holocene peat. The concentration of SAV averaged 0.2 g kg-l in a 0.5 m thick soil layer at the Tuckean Swamp, but was an order of magnitude lower in the oxic/anoxic transition layers at McLeods Creek and Bungawalbyn Swamp. The SAV mineral greigite (Fe3S4) was identified in the Tuckean Swamp by X-ray diffraction and scanning electron microscopy with quantitative energy dispersive X-ray analysis (SEM-EDX). Very small concentrations of greigite were also observed in the McLeods Creek, based on crystal morphology and elemental composition. The concentration of SAV was a small fraction of the total reduced sulfur, representing at most 3% of the Pyrite sulfur. However, the presence of this highly reactive sulfide mineral, distributed within pores where oxygen diffusion is most rapid, has important implications to the potential rate of acid production from these sediments.展开更多
This study aimed at investigating the causes of floods in Numan Town with particular reference to the 2012 floods. Three residential areas： Gangare, Gwadda Mallam and Green Village were selected for the study. Hydrol...This study aimed at investigating the causes of floods in Numan Town with particular reference to the 2012 floods. Three residential areas： Gangare, Gwadda Mallam and Green Village were selected for the study. Hydrological, SRTM （shuttle radar topography mission） digital elevation model, secondary and primary data were utilized. A total of 180 questionnaires were administered to the residents in equal proportion using systematic random sampling. ArcGIS 10.0 and Excel were used for the analysis. The study revealed that the major causes of flood in the area include discharge of water from the Lagdo dam in Cameroon and Kiri dam in Adamawa State. Others include heavy rainfall, topography, and lack of adherence to development control provisions which resulted in construction of residential areas on flood plains. Many of the residents do not have legal title to their plots and this constitutes a very serious constraint to provision of drainages and solid waste disposal services. To ameliorate the devastating effects of floods, the study recommends relocation of residents of flood prone areas, provision of solid waste management services, and construction of more drainages. In addition, the town planning authorities and community leaders should collaborate to ensure that houses are built in flood plains.展开更多
Majority of shallow floodplain lake ecosystems of the middle and lower reaches of the Yangtze River(China) have gone through serious eutrophication problems over the recent past. The severe environmental deterioration...Majority of shallow floodplain lake ecosystems of the middle and lower reaches of the Yangtze River(China) have gone through serious eutrophication problems over the recent past. The severe environmental deterioration accompanied by cyanobacterial blooms have become major water resource management challenges in the region. An advanced research method is urgently needed to tackle these challenges. The concept of ecological resilience address pressing questions of non-linear dynamics, threshold effects and regime shifts in shallow floodplain lakes, and help manage the ecosystem effectively. Palaeolimnological techniques are important for assessing long term resilience and associated thresholds effects of shallow lake ecosystems. However, the lack of reliable proxy methods available, the assessment of long term ecological resilience of shallow Yangtze River lake systems has become increasingly difficult. Cladocerans(water fleas) play a central role in lacustrine food webs by responding to external drivers and internal ecosystem processes in lakes. Their subfossils are well preserved and becoming one of potential proxy indicators of lake ecosystems change for a longer time scale. This study explores the potential application of subfossil cladocerans and their ephippia in assessing a long term ecological resilience and help better management strategies of lake ecosystems and water resources of the middle and lower reaches of the Yangtze River in China.展开更多
基金Under the auspices of National Key Research and Development Program of China(No.2016YFC0500403)National Natural Science Foundation of China(No.41471079,41571191,41671087)Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences(No.IGA-135-05)
文摘Northeast China is the region with the largest area of wetlands in China. The Sanjiang Plain and the Songnen Plain are large freshwater marsh distribution regions that are affected by climate warming and by the increasing frequency and density of extreme weather and are the regions most subject to disturbances by human activities in Northeast China. The wetlands of the Sanjiang Plain and the Songnen Plain have shrunk severely in the past 60 years, and wetland functions have been reduced substantially because of climate change, unreasonable land use, fire episodes, engineering and construction works and urbanization. Large-scale agricultural development started in the 1950 s has been the most important driving factor for wetland loss and degradation in the Sanjiang Plain. Water shortage has been the most important factor for degradation and fragmentation of wetlands in the Songnen Plain. To mitigate wetland degradation and better protect wetlands, special regulations, long-term mechanisms and technical support of wetland protection should be established. A wetland compensation program should be implemented, and technologies for increasing the adaptive capacity of wetlands should be developed. Moreover, it is most important to find the balanced threshold between agricultural development and wetland protection.
基金Project (No. 41004) supported by the Cooperative Research Center for Sustainable Tourism, Australia.
文摘The distribution of iron monosulfide (quantified as acid volatile sulfur: SAV) was compared with geo- chemical properties that are known to affect its formation and accumulation in three coastal Holocene acid sulfate soils (ASS) at Tuckean Swamp, McLeods Creek and Bungawalbyn Swamp respectively. These properties included PH, reactive iron (FeR), pore-water sulfate (SO:42-) and organic carbon (OC). Iron monosulfide was concentrated at the oxic/anoxic boundary. The Tuckean Swamp and McLeods Creek sites are Holocene sediments, whereas the Bungawalbyn Swamp is a Holocene peat. The concentration of SAV averaged 0.2 g kg-l in a 0.5 m thick soil layer at the Tuckean Swamp, but was an order of magnitude lower in the oxic/anoxic transition layers at McLeods Creek and Bungawalbyn Swamp. The SAV mineral greigite (Fe3S4) was identified in the Tuckean Swamp by X-ray diffraction and scanning electron microscopy with quantitative energy dispersive X-ray analysis (SEM-EDX). Very small concentrations of greigite were also observed in the McLeods Creek, based on crystal morphology and elemental composition. The concentration of SAV was a small fraction of the total reduced sulfur, representing at most 3% of the Pyrite sulfur. However, the presence of this highly reactive sulfide mineral, distributed within pores where oxygen diffusion is most rapid, has important implications to the potential rate of acid production from these sediments.
文摘This study aimed at investigating the causes of floods in Numan Town with particular reference to the 2012 floods. Three residential areas： Gangare, Gwadda Mallam and Green Village were selected for the study. Hydrological, SRTM （shuttle radar topography mission） digital elevation model, secondary and primary data were utilized. A total of 180 questionnaires were administered to the residents in equal proportion using systematic random sampling. ArcGIS 10.0 and Excel were used for the analysis. The study revealed that the major causes of flood in the area include discharge of water from the Lagdo dam in Cameroon and Kiri dam in Adamawa State. Others include heavy rainfall, topography, and lack of adherence to development control provisions which resulted in construction of residential areas on flood plains. Many of the residents do not have legal title to their plots and this constitutes a very serious constraint to provision of drainages and solid waste disposal services. To ameliorate the devastating effects of floods, the study recommends relocation of residents of flood prone areas, provision of solid waste management services, and construction of more drainages. In addition, the town planning authorities and community leaders should collaborate to ensure that houses are built in flood plains.
基金supported by the National Key Basic Research and Development Program of China (Grant No. 2017YFA0605200)the National Natural Science Foundation of China (Grant Nos. 41530753 & 41772378)+1 种基金One Hundred Talent Program of the Chinese Academy of Sciences (Grant No. Y6SL011001)Giri Kattel would like to acknowledge the CAS-PIFI Professorial Fellowship Program (Grant No. 2016VEA050) at Nanjing Institute of Geography and Limnology Chinese Academy of Sciences (NIGLAS)
文摘Majority of shallow floodplain lake ecosystems of the middle and lower reaches of the Yangtze River(China) have gone through serious eutrophication problems over the recent past. The severe environmental deterioration accompanied by cyanobacterial blooms have become major water resource management challenges in the region. An advanced research method is urgently needed to tackle these challenges. The concept of ecological resilience address pressing questions of non-linear dynamics, threshold effects and regime shifts in shallow floodplain lakes, and help manage the ecosystem effectively. Palaeolimnological techniques are important for assessing long term resilience and associated thresholds effects of shallow lake ecosystems. However, the lack of reliable proxy methods available, the assessment of long term ecological resilience of shallow Yangtze River lake systems has become increasingly difficult. Cladocerans(water fleas) play a central role in lacustrine food webs by responding to external drivers and internal ecosystem processes in lakes. Their subfossils are well preserved and becoming one of potential proxy indicators of lake ecosystems change for a longer time scale. This study explores the potential application of subfossil cladocerans and their ephippia in assessing a long term ecological resilience and help better management strategies of lake ecosystems and water resources of the middle and lower reaches of the Yangtze River in China.
