The Zhalong wetland,a Ramsar listed wetland in China,which is located in the lower reaches of theWuyu’er River,perennially takes in lots of nutrient input of N and P from around the catchment.Nutrient substanceswere ...The Zhalong wetland,a Ramsar listed wetland in China,which is located in the lower reaches of theWuyu’er River,perennially takes in lots of nutrient input of N and P from around the catchment.Nutrient substanceswere especially accumulated in the shallowlakes owning to the low-lying topography.The Xianhe Lake,where is loca-ted in buffer zone of the Zhalong wetland reserve,was chosen as our target area.The spatial variation of nutrient sub-stances in the shallow lakes was discussed and its influence factors were pointed out.The results showed that nitrogenand phosphorus in the wetland water existed mainly in the form of organic ones.The concentration of total nitrogen(TN)ranged from 0.65 mg/L to 10.64 mg/L and total phosphorus(TP) ranged from 0.013 mg/L to 0.052 mg/L.Ratio ofN/P was between 25.6 and 206.5.The water quality of the Xianhe Lake has been contaminated and is in heavy eutroph-ication.Total P has been acting as the major limiting factor.The distribution pattern of nitrogen and phosphorus in wet-land water showed characteristics of internal release except for the stream mouth area.There,the vertical distributions ofnitrogen and phosphorus nutrients were from both exterior source and internal release,and was mainly influenced by ex-terior source during flood period.Strong hydrodynamic disturb contributed to nitrogen and phosphorus nutrients suspen-ding and releasing in the sediments.The nutrients distribution in the water varied independent on regional changes ofdifferent frequency of hydrodynamic disturb.Mineralization and denitrification might be promoted in high frequency hy-drodynamic disturb area.In growing period,the absorption ofPhragmitesto nutrients was an important mechanism of nu-trients descending and spatial variation in the shallow lake.展开更多
Wetlands play a key role in regulating local climate as well as reducing impacts caused by climate change. Rapid observations of the land surface temperature(LST) are, therefore, valuable for studying the dynamics of ...Wetlands play a key role in regulating local climate as well as reducing impacts caused by climate change. Rapid observations of the land surface temperature(LST) are, therefore, valuable for studying the dynamics of wetland systems. With the development of thermal remote sensing technology, LST retrieval with satellite images is a practicable way to detect a wetland and its neighboring area’s thermal environment from a non-point visual angle rather than the traditional detection from a point visual angle. The mono-windows(MW) method of retrieving LST was validated. On the basis of estimated LST, we used Geographical Information System(GIS) technology to study the impact of wetland reclamation on local temperatures at a regional scale. Following that, correlations between LST and the wetland were analyzed. The results show that: 1) It is feasible to retrieve the LST from Landsat 8 OLI satellite images with MW model. The model was validated with the land surface temperature observed in four meteorological stations when the satellite scanned the study region. The satellite retrieval error was approximately 1.01°C. 2) The relationship between the spatial distribution of land surface temperatures and the Zhalong wetland was analyzed based on GIS technology. The results show that wetland has an obvious influence on LST, and that this influence decreases with increasing distance from the wetland. When the distance from the wetland was less than 500 m, its influence on LST was significant. Results also illustrated that the effect of the wetland’s different land use/land cover’s LST distribution varied with different seasons.展开更多
Evapotranspiration (ET) process of plants is controlled by several factors. Besides the physiological factors of plants, height, density, LAI (leaf area index), etc., the change of meteorological factors, such as radi...Evapotranspiration (ET) process of plants is controlled by several factors. Besides the physiological factors of plants, height, density, LAI (leaf area index), etc., the change of meteorological factors, such as radiation, temperature, wind and precipitation, can influence ET process evidently, thus remodeling the spatial and temporal distribution of ET. In order to illuminate the effects of meteorological factors on wetland ET, the ET of Zhalong Wetland was calculated from 1961 to 2000, the statistical relationships (models) between ET and maximum temperature (Tmax), minimum temperature (Tmin), precipitation (P) and wind speed at 2m height (U2) were established, and the sensitivity analysis of the variables in the model was performed. The results show that Tmax and Tmin are two dominating factors that influence ET markedly, and the difference of rising rate between Tmax and Tmin determines the change trend of ET. With the climatic scenarios of four General Circulation Models (GCMs), the ET from 2001 to 2060 was predicted by the statistical model. Compared to the period of 1961-2000, the water consumption by ET will increase greatly in the future. According to the scenarios, the rise of Tmax (about 1.5℃ to 3.3℃) and Tmin (about 1.7℃ to 3.5℃) will cause an additional water con- sumption of 14.0%-17.8% for reed swamp. The ecological water demand in Zhalong Wetland will become more severe.展开更多
The water purification function of natural wetland systems is widely recognized,but rarely studied or scientifically evaluated.Extensive studies have been carried out by various international wetland research communit...The water purification function of natural wetland systems is widely recognized,but rarely studied or scientifically evaluated.Extensive studies have been carried out by various international wetland research communities to quantify the water quality improvement ability of the natural wetlands,in order to maintain such ability and wetland ecological health.This study aims to evaluate the purification function of Zhalong Wetland in China for removing total nitrogen(TN) and phosphorus(TP),based on ex-situ experiments and the development of a combined water quantity-quality model.Experiments and model predictions were carried out with different input TP and TN concentrations.Statistical analyses demonstrated that the relative errors between model simulations and experimental observations for TN and TP were 8.6% and 12.4%,respectively.With water retention time being maintained at 90 d,the removal rate of these pollutants could not reach the required Grade V standards,if the inflow TN concentration was over 42 mg L-1,or the input TP concentration was over 14 mg L-1.The simulation results also demonstrated that,even with Grade V quality standard compliance,when the water inflow from surrounding industries and agriculture lands into Zhalong Wetland reaches 0.3×10 8 m 3 a-1,the maximum TN and TP loads that the reserve can cope with are 1.26×10 3 t a-1 and 0.42×10 3 t a-1,respectively.Overall,this study has produced a significant amount of information that can be used for the protection of water quality and ecological health of Zhalong Wetland.展开更多
基金President Scholarship of Chinese Academy of Sciences
文摘The Zhalong wetland,a Ramsar listed wetland in China,which is located in the lower reaches of theWuyu’er River,perennially takes in lots of nutrient input of N and P from around the catchment.Nutrient substanceswere especially accumulated in the shallowlakes owning to the low-lying topography.The Xianhe Lake,where is loca-ted in buffer zone of the Zhalong wetland reserve,was chosen as our target area.The spatial variation of nutrient sub-stances in the shallow lakes was discussed and its influence factors were pointed out.The results showed that nitrogenand phosphorus in the wetland water existed mainly in the form of organic ones.The concentration of total nitrogen(TN)ranged from 0.65 mg/L to 10.64 mg/L and total phosphorus(TP) ranged from 0.013 mg/L to 0.052 mg/L.Ratio ofN/P was between 25.6 and 206.5.The water quality of the Xianhe Lake has been contaminated and is in heavy eutroph-ication.Total P has been acting as the major limiting factor.The distribution pattern of nitrogen and phosphorus in wet-land water showed characteristics of internal release except for the stream mouth area.There,the vertical distributions ofnitrogen and phosphorus nutrients were from both exterior source and internal release,and was mainly influenced by ex-terior source during flood period.Strong hydrodynamic disturb contributed to nitrogen and phosphorus nutrients suspen-ding and releasing in the sediments.The nutrients distribution in the water varied independent on regional changes ofdifferent frequency of hydrodynamic disturb.Mineralization and denitrification might be promoted in high frequency hy-drodynamic disturb area.In growing period,the absorption ofPhragmitesto nutrients was an important mechanism of nu-trients descending and spatial variation in the shallow lake.
基金Under the auspices of National Key Research and Development Program of China(No.2016YFA0602301-1)Strategic Planning Project of Northeast Institute of Geography and Agroecology(IGA)Chinese Academy of Sciences(No.Y6H2091001)
文摘Wetlands play a key role in regulating local climate as well as reducing impacts caused by climate change. Rapid observations of the land surface temperature(LST) are, therefore, valuable for studying the dynamics of wetland systems. With the development of thermal remote sensing technology, LST retrieval with satellite images is a practicable way to detect a wetland and its neighboring area’s thermal environment from a non-point visual angle rather than the traditional detection from a point visual angle. The mono-windows(MW) method of retrieving LST was validated. On the basis of estimated LST, we used Geographical Information System(GIS) technology to study the impact of wetland reclamation on local temperatures at a regional scale. Following that, correlations between LST and the wetland were analyzed. The results show that: 1) It is feasible to retrieve the LST from Landsat 8 OLI satellite images with MW model. The model was validated with the land surface temperature observed in four meteorological stations when the satellite scanned the study region. The satellite retrieval error was approximately 1.01°C. 2) The relationship between the spatial distribution of land surface temperatures and the Zhalong wetland was analyzed based on GIS technology. The results show that wetland has an obvious influence on LST, and that this influence decreases with increasing distance from the wetland. When the distance from the wetland was less than 500 m, its influence on LST was significant. Results also illustrated that the effect of the wetland’s different land use/land cover’s LST distribution varied with different seasons.
基金Under the auspices of the National Natural Science Foundation of China (No. 50139020)
文摘Evapotranspiration (ET) process of plants is controlled by several factors. Besides the physiological factors of plants, height, density, LAI (leaf area index), etc., the change of meteorological factors, such as radiation, temperature, wind and precipitation, can influence ET process evidently, thus remodeling the spatial and temporal distribution of ET. In order to illuminate the effects of meteorological factors on wetland ET, the ET of Zhalong Wetland was calculated from 1961 to 2000, the statistical relationships (models) between ET and maximum temperature (Tmax), minimum temperature (Tmin), precipitation (P) and wind speed at 2m height (U2) were established, and the sensitivity analysis of the variables in the model was performed. The results show that Tmax and Tmin are two dominating factors that influence ET markedly, and the difference of rising rate between Tmax and Tmin determines the change trend of ET. With the climatic scenarios of four General Circulation Models (GCMs), the ET from 2001 to 2060 was predicted by the statistical model. Compared to the period of 1961-2000, the water consumption by ET will increase greatly in the future. According to the scenarios, the rise of Tmax (about 1.5℃ to 3.3℃) and Tmin (about 1.7℃ to 3.5℃) will cause an additional water con- sumption of 14.0%-17.8% for reed swamp. The ecological water demand in Zhalong Wetland will become more severe.
基金supported by the Knowledge Innovation Programs of Chinese Academy of Sciences (Grant No. KZCX2-YW-Q06-2)the National Basic Research Program of China ("973" Program) (Grant No.2010CB428404)
文摘The water purification function of natural wetland systems is widely recognized,but rarely studied or scientifically evaluated.Extensive studies have been carried out by various international wetland research communities to quantify the water quality improvement ability of the natural wetlands,in order to maintain such ability and wetland ecological health.This study aims to evaluate the purification function of Zhalong Wetland in China for removing total nitrogen(TN) and phosphorus(TP),based on ex-situ experiments and the development of a combined water quantity-quality model.Experiments and model predictions were carried out with different input TP and TN concentrations.Statistical analyses demonstrated that the relative errors between model simulations and experimental observations for TN and TP were 8.6% and 12.4%,respectively.With water retention time being maintained at 90 d,the removal rate of these pollutants could not reach the required Grade V standards,if the inflow TN concentration was over 42 mg L-1,or the input TP concentration was over 14 mg L-1.The simulation results also demonstrated that,even with Grade V quality standard compliance,when the water inflow from surrounding industries and agriculture lands into Zhalong Wetland reaches 0.3×10 8 m 3 a-1,the maximum TN and TP loads that the reserve can cope with are 1.26×10 3 t a-1 and 0.42×10 3 t a-1,respectively.Overall,this study has produced a significant amount of information that can be used for the protection of water quality and ecological health of Zhalong Wetland.
文摘[目的]准确了解2010年以来扎龙自然保护区生态变化,为提高湿地生态系统服务价值评估能力提供数据支持和理论参考。[方法]基于遥感、气象、地面协同观测数据,利用CASA(Carnegie-Ames-Stanford Approach)模型、GSMSR(Geostatistical Model of Soil Respiration)模型和回归分析等统计方法,分析气候变化对2010—2020年扎龙自然保护区土地覆盖、植被生态质量、净生态系统生产力(NEP)等的影响。[结果](1)扎龙自然保护区的主要土地覆盖类型为有水草甸,占保护区面积的37.24%,主要分布在核心区,但面积总体呈下降趋势;(2)植被覆盖度呈波动增长趋势,年最高植被覆盖度平均为74.62%;(3)植被生态质量指数呈增加趋势,2019,2020年处于“好”等级;NEP平均为253.59 g/(m^(2)·a)(以C计),呈现东高西低的空间分布特征;(4)生长季平均固碳量为5.69×10^(5) t/a,释氧量1.52×10^(6) t/a,均存在上升趋势;(5)气温对生态监测指标的影响大于降水量。[结论]扎龙自然保护区是嫩江流域生态最为脆弱的区域,植被生产力受气候影响大,需要加强生态保护和修复。
