The pollution of aquatic ecosystem by heavy metals has assumed serious proportions due to their toxicity and accumulative behavior. The toxicity metal is dependent on its chemical form and therefore removal of metal i...The pollution of aquatic ecosystem by heavy metals has assumed serious proportions due to their toxicity and accumulative behavior. The toxicity metal is dependent on its chemical form and therefore removal of metal is more meaningful than the estimation of its concentrations. In this study, the batch experiments were carried out under 30℃ to study the effect of pH, initial Cr concentration, adsorbent dose and contact time on the removal of Cr （lII）. The maximum adsorption efficiency （99%） was observed when 1.5 g of pond mud was used for removal ofCr （Ⅲ） from test solution containing 150 mg·Cr / 100 ml. The optimal pH and contact time recorded during the study were 6 and 10.0, respectively.展开更多
In the U.S.Southwest,global climate change,acting in concert with extant stressors such as urbanization and over-allocation of water resources,is changing ecosystems in measureable and sometimes dramatic ways.Twenty-f...In the U.S.Southwest,global climate change,acting in concert with extant stressors such as urbanization and over-allocation of water resources,is changing ecosystems in measureable and sometimes dramatic ways.Twenty-first century projections indicate accelerating climate change and cascading ecological consequences.Effects observed to date include large-scale forest dieback,large and severe wildfires,and changes in the flow regimes of rivers and streams with attendant changes to riparian and aquatic ecosystems.Rising temperatures and changing precipitation patterns are pushing ecosystems across physiological and ecological thresholds,causing widespread mortality and,in some cases,major changes in composition,structure and function.These changes have prompted action by the conservation community to reduce the adverse effects of climate change.The Southwest Climate Change Initiative(SWCCI),a project led by The Nature Conservancy,works with local stakeholders in affected landscapes,reduces adverse impacts on ecological and social systems using scientific knowledge and practical tools.The Initiative has learned through practical experience that: 1) managers must embrace change and manage for resilience rather than resistance;2) strong local science-management partnerships are critical to effective adaptation planning and implementation;3) planners and managers must broaden the scope and accelerate the pace of conservation activities if ecosystem services are to be sustained;4) adaptation often does not require radically new or different management practices,rather,conservationists already have many of the tools they need;and 5) rapid documentation and widespread communication of methods and findings can build rapidly regional capacity for climate change adaptation.Our experience suggests that adaptation efforts can be effective if they are focused at the local scale;employ learning networks;and engage in ecosystem-based adaptation:the sustainable management,conservation and restoration of ecosystems so that they continue to provide the services that allow people to thrive in changing environments.展开更多
Contribution of first flush runoff events from intense rainfall to downstream aquatic ecosystems are often reported in terms of sediment and nutrient delivery, with hardly any consideration to the contribution that st...Contribution of first flush runoff events from intense rainfall to downstream aquatic ecosystems are often reported in terms of sediment and nutrient delivery, with hardly any consideration to the contribution that standing, concentrated tailwater in primary aquatic systems makes to downstream nutrient loads. Two geographically distinct studies （Jonesboro Arkansas, and Stoneville Mississippi; 4 studies, n = 30） evaluated the effectiveness of drainage ditch systems to mitigate nutrient concentrations and loads. Within each independent study all experimental ditches had elevated background nutrient concentrations as a result of standing water, prior to the start of each simulated runoff experiment. These concentrations remained elevated 15-30 minutes post the start of each simulation as the concentrated, impounded water was pushed out through each system. In both these systems, it was hypothesized that water had accumulated in the respective drainage ditches and had been concentrated though evaporation and aquatic macrophyte transpiration. It is theorized that additional controlled drainage with improved dilution and hydraulic residence management.展开更多
The study of waters ecosystem and their population carrying capacity demonstrates the role of these ecosystems in economic and social development and provides a theoretical basis for the management and allocation of a...The study of waters ecosystem and their population carrying capacity demonstrates the role of these ecosystems in economic and social development and provides a theoretical basis for the management and allocation of aquatic ecosystems. In this study, the concept of waters ecosystem population carrying capacity was defined and developmental trends in the population carrying capacity of waters ecosystem in China were evaluated. Results show that waters ecosystem population carrying capacity in China increased from 0.176×109 person year-1 in 2000 to 0.255 × 109 person year-1 in 2010; the population carrying capacity of the standard sea remained at 0.2-0.3 person ha 1; and the standard inland waters population carrying capacity increased from 1.8 to 3.2 person ha-1. This analysis indicates notable regional difference in waters population carrying capacity. In southeastern coastal China and Yangtze River drainage areas where inland waters are widely distributed and aquaculture is developed, the population carrying capacity is higher; however, in northwest China where water resource are deficient and the distribution is relatively small, the waters population carrying capacity is low. The waters ecosystem population carrying capacity of China in 2030 was predicted and results indicate strong potential for increasing waters population carrying capacity.展开更多
文摘The pollution of aquatic ecosystem by heavy metals has assumed serious proportions due to their toxicity and accumulative behavior. The toxicity metal is dependent on its chemical form and therefore removal of metal is more meaningful than the estimation of its concentrations. In this study, the batch experiments were carried out under 30℃ to study the effect of pH, initial Cr concentration, adsorbent dose and contact time on the removal of Cr （lII）. The maximum adsorption efficiency （99%） was observed when 1.5 g of pond mud was used for removal ofCr （Ⅲ） from test solution containing 150 mg·Cr / 100 ml. The optimal pH and contact time recorded during the study were 6 and 10.0, respectively.
文摘In the U.S.Southwest,global climate change,acting in concert with extant stressors such as urbanization and over-allocation of water resources,is changing ecosystems in measureable and sometimes dramatic ways.Twenty-first century projections indicate accelerating climate change and cascading ecological consequences.Effects observed to date include large-scale forest dieback,large and severe wildfires,and changes in the flow regimes of rivers and streams with attendant changes to riparian and aquatic ecosystems.Rising temperatures and changing precipitation patterns are pushing ecosystems across physiological and ecological thresholds,causing widespread mortality and,in some cases,major changes in composition,structure and function.These changes have prompted action by the conservation community to reduce the adverse effects of climate change.The Southwest Climate Change Initiative(SWCCI),a project led by The Nature Conservancy,works with local stakeholders in affected landscapes,reduces adverse impacts on ecological and social systems using scientific knowledge and practical tools.The Initiative has learned through practical experience that: 1) managers must embrace change and manage for resilience rather than resistance;2) strong local science-management partnerships are critical to effective adaptation planning and implementation;3) planners and managers must broaden the scope and accelerate the pace of conservation activities if ecosystem services are to be sustained;4) adaptation often does not require radically new or different management practices,rather,conservationists already have many of the tools they need;and 5) rapid documentation and widespread communication of methods and findings can build rapidly regional capacity for climate change adaptation.Our experience suggests that adaptation efforts can be effective if they are focused at the local scale;employ learning networks;and engage in ecosystem-based adaptation:the sustainable management,conservation and restoration of ecosystems so that they continue to provide the services that allow people to thrive in changing environments.
文摘Contribution of first flush runoff events from intense rainfall to downstream aquatic ecosystems are often reported in terms of sediment and nutrient delivery, with hardly any consideration to the contribution that standing, concentrated tailwater in primary aquatic systems makes to downstream nutrient loads. Two geographically distinct studies （Jonesboro Arkansas, and Stoneville Mississippi; 4 studies, n = 30） evaluated the effectiveness of drainage ditch systems to mitigate nutrient concentrations and loads. Within each independent study all experimental ditches had elevated background nutrient concentrations as a result of standing water, prior to the start of each simulated runoff experiment. These concentrations remained elevated 15-30 minutes post the start of each simulation as the concentrated, impounded water was pushed out through each system. In both these systems, it was hypothesized that water had accumulated in the respective drainage ditches and had been concentrated though evaporation and aquatic macrophyte transpiration. It is theorized that additional controlled drainage with improved dilution and hydraulic residence management.
基金Projects of Strategic S&T Plan of IGSNRR(No.2012ZD007)projects of China geological survey(No.12120114006401)
文摘The study of waters ecosystem and their population carrying capacity demonstrates the role of these ecosystems in economic and social development and provides a theoretical basis for the management and allocation of aquatic ecosystems. In this study, the concept of waters ecosystem population carrying capacity was defined and developmental trends in the population carrying capacity of waters ecosystem in China were evaluated. Results show that waters ecosystem population carrying capacity in China increased from 0.176×109 person year-1 in 2000 to 0.255 × 109 person year-1 in 2010; the population carrying capacity of the standard sea remained at 0.2-0.3 person ha 1; and the standard inland waters population carrying capacity increased from 1.8 to 3.2 person ha-1. This analysis indicates notable regional difference in waters population carrying capacity. In southeastern coastal China and Yangtze River drainage areas where inland waters are widely distributed and aquaculture is developed, the population carrying capacity is higher; however, in northwest China where water resource are deficient and the distribution is relatively small, the waters population carrying capacity is low. The waters ecosystem population carrying capacity of China in 2030 was predicted and results indicate strong potential for increasing waters population carrying capacity.
