Yanhu Lake basin(YHB)is a typical alpine lake on the northeastern Tibetan Plateau(TP).Its continuous expansion in recent years poses serious threats to downstream major projects.As a result,studies of the mechanisms u...Yanhu Lake basin(YHB)is a typical alpine lake on the northeastern Tibetan Plateau(TP).Its continuous expansion in recent years poses serious threats to downstream major projects.As a result,studies of the mechanisms underlying lake expansion are urgently needed.The elasticity method within the Budyko framework was used to calculate the water balance in the Yanhu Lake basin(YHB)and the neighboring Tuotuo River basin(TRB).Results show intensification of hydrological cycles and positive trends in the lake area,river runoff,precipitation,and potential evapotranspiration.Lake expansion was significant between 2001 and 2020 and accelerated between 2015 and 2020.Precipitation increase was the key factor underlying the hydrological changes,followed by glacier meltwater and groundwater.The overflow of Yanhu Lake was inevitable because it was connected to three other lakes and the water balance of all four lakes was positive.The high salinity lake water diverted downstream will greatly impact the water quality of the source area of the Yangtze River and the stability of the permafrost base of the traffic corridor.展开更多
Background:Reproducing populations of invasive carps(Hypophthalmichthys spp.)could alter aquatic food webs and negatively afect native fshes in the Mississippi National River and Recreation Area(MISS)and the St.Croix ...Background:Reproducing populations of invasive carps(Hypophthalmichthys spp.)could alter aquatic food webs and negatively afect native fshes in the Mississippi National River and Recreation Area(MISS)and the St.Croix National Scenic Riverway(SACN).However,proposed invasive carp barriers may also threaten populations of native migratory fshes by preventing movements of fsh between rivers that are necessary for life history requirements.In this study,nonlethal chemical techniques were used to provide baseline data related to the condition,trophic position,and migratory histories of lake sturgeon(Acipenser fulvescens)captured in the Mississippi and St.Croix Rivers.Results:Fish length and weight measurements and age estimates determined from pectoral fn rays demonstrated that lake sturgeon from the Mississippi River had greater lengths-at-age compared to sturgeon from the St.Croix River.However,length–weight relations were similar for sturgeon from the Mississippi and St.Croix Rivers.Lake sturgeon captured from diferent locations had distinguishable fatty acid signatures,and stable isotope analyses demonstrated that lake sturgeon from the Mississippi River generally feed at a higher trophic level than those in the St.Croix River.Strontium-to-calcium ratios(Sr:Ca)from fn ray cross sections indicated that sturgeon captured from the Mississippi River had higher Sr:Ca values than sturgeon captured from the St.Croix River,and natal origins and capture locations were not signifcantly diferent among sturgeon captured within individual rivers.Most sturgeon were captured in water with a similar Sr:Ca signature as their natal waters,indicating that there is some separation between populations of lake sturgeon in the St.Croix and Mississippi Rivers.However,Sr:Ca data indicated substantial variation in movement patterns among individual lake sturgeon,indicating that populations interact through migrations of individual fsh between rivers.Conclusions:Study results provide baseline condition and food web structure index data for assessing changes in lake sturgeon populations should invasive carps become established in these areas of the Mississippi and St.Croix Rivers.Controlled-exposure and telemetry studies would help verify and enhance the relations between Sr:Ca signatures in water and lake sturgeon pectoral fn rays to further assess mixing of sturgeons between rivers。展开更多
基金funded by the National Natural Science Foundation of China(42002264)the China Geological Survey Program(DD20230537)the Fundamental Research Funds for the Central Public Research Institutes(SK202006).
文摘Yanhu Lake basin(YHB)is a typical alpine lake on the northeastern Tibetan Plateau(TP).Its continuous expansion in recent years poses serious threats to downstream major projects.As a result,studies of the mechanisms underlying lake expansion are urgently needed.The elasticity method within the Budyko framework was used to calculate the water balance in the Yanhu Lake basin(YHB)and the neighboring Tuotuo River basin(TRB).Results show intensification of hydrological cycles and positive trends in the lake area,river runoff,precipitation,and potential evapotranspiration.Lake expansion was significant between 2001 and 2020 and accelerated between 2015 and 2020.Precipitation increase was the key factor underlying the hydrological changes,followed by glacier meltwater and groundwater.The overflow of Yanhu Lake was inevitable because it was connected to three other lakes and the water balance of all four lakes was positive.The high salinity lake water diverted downstream will greatly impact the water quality of the source area of the Yangtze River and the stability of the permafrost base of the traffic corridor.
基金funded by the National Resource Preservation Program,a nation-wide collaborative program,supported by the USGS Ecosystems Mission Area,through which USGS and National Park Service staf address priority research needs identifed by the National Park ServiceNational Park Service staf from the two National Park Service units represented in this study were involved in the development of the study proposalThe study proposal was reviewed and approved for funding by a panel of U.S.Geological Survey and National Park Service scientists.
文摘Background:Reproducing populations of invasive carps(Hypophthalmichthys spp.)could alter aquatic food webs and negatively afect native fshes in the Mississippi National River and Recreation Area(MISS)and the St.Croix National Scenic Riverway(SACN).However,proposed invasive carp barriers may also threaten populations of native migratory fshes by preventing movements of fsh between rivers that are necessary for life history requirements.In this study,nonlethal chemical techniques were used to provide baseline data related to the condition,trophic position,and migratory histories of lake sturgeon(Acipenser fulvescens)captured in the Mississippi and St.Croix Rivers.Results:Fish length and weight measurements and age estimates determined from pectoral fn rays demonstrated that lake sturgeon from the Mississippi River had greater lengths-at-age compared to sturgeon from the St.Croix River.However,length–weight relations were similar for sturgeon from the Mississippi and St.Croix Rivers.Lake sturgeon captured from diferent locations had distinguishable fatty acid signatures,and stable isotope analyses demonstrated that lake sturgeon from the Mississippi River generally feed at a higher trophic level than those in the St.Croix River.Strontium-to-calcium ratios(Sr:Ca)from fn ray cross sections indicated that sturgeon captured from the Mississippi River had higher Sr:Ca values than sturgeon captured from the St.Croix River,and natal origins and capture locations were not signifcantly diferent among sturgeon captured within individual rivers.Most sturgeon were captured in water with a similar Sr:Ca signature as their natal waters,indicating that there is some separation between populations of lake sturgeon in the St.Croix and Mississippi Rivers.However,Sr:Ca data indicated substantial variation in movement patterns among individual lake sturgeon,indicating that populations interact through migrations of individual fsh between rivers.Conclusions:Study results provide baseline condition and food web structure index data for assessing changes in lake sturgeon populations should invasive carps become established in these areas of the Mississippi and St.Croix Rivers.Controlled-exposure and telemetry studies would help verify and enhance the relations between Sr:Ca signatures in water and lake sturgeon pectoral fn rays to further assess mixing of sturgeons between rivers。
