Modern hydrobiology,mainly,is based on conception,which may be named Conception of unicity of ecosystem stable state(CUESS):Mature ecosystems are stable and in dynamic equilibrium.Ecosystem state fluctuates around
Lake ecosystems are recognized as“sentinels”of regional climate and environmental change(Loewen,2023).Research over recent decades has established that climate change—through mechanisms such as warming and extreme ...Lake ecosystems are recognized as“sentinels”of regional climate and environmental change(Loewen,2023).Research over recent decades has established that climate change—through mechanisms such as warming and extreme weather events—significantly impacts lake water quality,biodiversity,and ecological functions(Woolway et al.,2020;Jane et al.,2021).展开更多
The study of trace metals in the atmosphere and lake water is important due to their critical effects on humans, aquatic animals and the geochemical balance of ecosystems. The objective of this study was to investigat...The study of trace metals in the atmosphere and lake water is important due to their critical effects on humans, aquatic animals and the geochemical balance of ecosystems. The objective of this study was to investigate the concentration of trace metals in atmospheric and lake water samples during the rainy season （before and after precipitation） between November and December 2015. Typical methods of sample preparation for trace metal determination such as cloud point extraction, solid phase extraction and dispersive liquid- liquid micro-extraction are time-consuming and difficult to perform; therefore, there is a crucial need for development of more effective sample preparation procedure. A convection microwave assisted digestion procedure for extraction of trace metals was developed for use prior to inductively couple plasma-mass spectrometric determination. The result showed that metals like zinc （133.50-419.30 μg/m3） and aluminum （53.58-378.93 μg/m3） had higher concentrations in atmospheric samples as compared to lake samples before precipitation. On the other hand, the concentrations of zinc, aluminum, chromium and arsenic were significantly higher in lake samples after precipitation and lower in atmospheric samples. The relationship between physicochemical parameters （pH and turbidity） and heavy metal concentrations was investigated as well. Furthermore, enrichment factor analysis indicated that anthropogenic sources such as soil dust, biomass burning and fuel combustion influenced the metal concentrations in the atmosphere.展开更多
The knowledge of prey small ?sh stock, distribution and abundance is necessary to guide stocking of piscivorous ?sh for the biomanipulation in domestic tap water lakes. This study describes the current status of small...The knowledge of prey small ?sh stock, distribution and abundance is necessary to guide stocking of piscivorous ?sh for the biomanipulation in domestic tap water lakes. This study describes the current status of small ?sh community in Kuilei Lake(China), and examines the spatial and seasonal variations of the community in relation to key environmental factors. Based on submerged macrophyte cover and water depth, the lake was divided into ?ve major habitats:(1) macrophyte covered shallow habitat of water depth< 2.00 m,(2) uncovered or less-covered shallow habitat(2.00 m–3.50 m),(3) uncovered medium shallow habitat(3.50 m–5.00 m),(4) uncovered medium deep habitat(5.00 m–6.50 m) and(5) uncovered deep habitat(6.50 m–8.50 m). The abundance and composition of small ?sh were monitored by benthic fykenet sampling from April 2013 to January 2014. A total of 2881 individuals belonging to 5 families and 21 species were collected. Based on their abundance(accounted for 88.96% of the total) and occurrence(more than 33.33%), Acheilognathus chankaensis, Acheilognathus macropterus, Microphysogobio microstomus,Pseudorasbora parva and Rhinogobius giurinus were recognized as dominant small ?sh species. The results of correlation analysis identi?ed that species richness( Sr), Shannon-Wiener diversity index( H′)and Margalef′s richness index( D) were signi?cantly negatively correlated with water depth, but positively correlated with biomass of submerged macrophytes.Redundancy analysis(RDA) revealed that the spatial distributions of most small ?shes were negatively associated with water depth. The details of these ?ndings are bene?cial to understanding the adaptation of the small ?shes in degraded environments, and to developing suitable biomanipulation strategies for the management of ?sh resources and water quality in the lakes along the lower reach of the Changjiang(Yangtze) River basin.展开更多
This paper provides some introductory information on the history, development, and characteristics of various lake ecosystem models. The modeling of lake ecological processes began to gain importance in the early 1960...This paper provides some introductory information on the history, development, and characteristics of various lake ecosystem models. The modeling of lake ecological processes began to gain importance in the early 1960s. There are a number of models available today, with varying levels of complexity to cope with the variety of environmental problems found in lake environments, e.g. eutrophication, acidification, oxygen depletion, wetland management, heavy metal and pesticide pollution, as well as hydrodynamic problems. In particular, this paper focuses on lake eutrophication and wetland models, as well as addressing strategies appropriate for the design and development of reliable lake ecological models.展开更多
The effects of stochastic perturbations and periodic excitations on the eutrophicated lake ecosystem are explored.Unlike the existing work in detecting early warning signals,this paper presents the most probable trans...The effects of stochastic perturbations and periodic excitations on the eutrophicated lake ecosystem are explored.Unlike the existing work in detecting early warning signals,this paper presents the most probable transition paths to characterize the regime shifts.The most probable transition paths are obtained by minimizing the Freidlin-Wentzell(FW)action functional and Onsager-Machlup(OM)action functional,respectively.The most probable path shows the movement trend of the lake eutrophication system under noise excitation,and describes the global transition behavior of the system.Under the excitation of Gaussian noise,the results show that the stability of the eutrophic state and the oligotrophic state has different results from two perspectives of potential well and the most probable transition paths.Under the excitation of Gaussian white noise and periodic force,we find that the transition occurs near the nearest distance between the stable periodic solution and the unstable periodic solution.展开更多
The presented article discusses the results of survey of the Most lake, which was created within hydric recultivation of the site of the former brown-coal mine Most Lezaky in northern Bohemia in the Czech Republic. Th...The presented article discusses the results of survey of the Most lake, which was created within hydric recultivation of the site of the former brown-coal mine Most Lezaky in northern Bohemia in the Czech Republic. The survey discovered plants which belong to ruderal, wetland, halophilic and xerothermal species based on their life strategy. The discovered endangered species include Carex secalina, Schoenoplectus tabaernemontani, Salsola call subsp. Rosacea and Tetragonolobus maritimus. A total of 350 species of vascular plants were discovered in the study area. During the monitoring, a total of 146 bird species were discovered. The monitored location can be currently considered as a significant gathering place namely for aquatic and wetland bird species during the winter period and the migration period （e.g., Tachybaptus ruficollis, Podiceps cristatus, Anser anser, Anas platyrhynchos, Anas strepera, Fulica atra and various species of Larus sp.） and as a significant area of occurrence of relatively rare species bound to anthropogenetically disturbed areas of mining and post-mining landscape （e.g., Anthus campestris, Anthus pratensis, Motacillaflava, Oenanthe oenanthe, Saxicola rubetra and Saxicola torquata）. Within the monitoring of the water quality, the saprobic index values （S） ranged in 2013 between 1.62 and 1.92.展开更多
Location & environmental features: Donghu Lake is located at 114°23′ E and 30°33′N in the eastern suburbs of the city of Wuhan, capital of Hubei Province in central China. It is a typical shallow-botto...Location & environmental features: Donghu Lake is located at 114°23′ E and 30°33′N in the eastern suburbs of the city of Wuhan, capital of Hubei Province in central China. It is a typical shallow-bottomed, freshwater ecosystem nestling in the middle reaches of the mighty Changjiang (Yangtze) River. With a total surface area of 27.8 square and a mean depth of 2.2 meters, it sprawls in a drainage basin covering an area of 187 square kilometers. The station is situated on the southwest bank of the lake.展开更多
Desert lake, a unique oasis in desert ecosystems, harbours different bacterial communities. Thus, it is considered as a hub of bacterial diversity. In this study, bacterial diversity in the sediment of Crescent Moon S...Desert lake, a unique oasis in desert ecosystems, harbours different bacterial communities. Thus, it is considered as a hub of bacterial diversity. In this study, bacterial diversity in the sediment of Crescent Moon Spring, Kumtag Desert, Northwest China was analyzed using high-throughput amplicon pyrosequencing analysis. The sequences of the most abundant OUTs （Operational Taxonomic Units） in the sediment of Crescent Moon Spring were compared with the sequences of those most abundant OUTs of various origins from NCBI GenBank database to detect the origins of bacteria in the sediment of Crescent Moon Spring. Also, bacterial compositions between sediment of Crescent Moon Spring and other desert and lake ecosystems （including desert lakes） worldwide were compared using cluster analysis to determine the possible factors affecting bacterial compositions. In total, 11,855 sequences were obtained and 30 phyla were identified. At the phylum level, the dominant phylum was Proteobacteria with α-Proteobacteria being the first dominant class and the second dominant phylum was Planctomycetes. Our finding that α-Proteobacteria being the first dominant class of Proteobacteria and Planctomycetes being the second dominant phyla are somewhat contradictory with reports from other desert lake sediments. This difference could be resulted from water hydration and conductivity, as well as oligotrophic conditions of Crescent Moon Spring. At the genus level, Rhodobacter, Caldilinea, Planctomyces, and Porphyrobacterwere the dominant genera in the sediment of Crescent Moon Spring. Comparisons on sequences of the most abundant OUTs （including OTU3615, OTU6535, and OTU6646） between sediment of Crescent Moon Spring and various origins from NCBI GenBank database indicate that the origins of bacteria in the sediment of Crescent Moon Spring are likely from the underground water. Furthermore, cluster analysis on comparisons of bacteria compositions between sediment of Crescent Moon Spring and other desert and lake ecosystems （including desert lakes） worldwide shows that at regional scales, bacterial compositions may be mainly affected by geographical patterns, precipitation amounts, and pH values. Collectively, our results provide new knowledge on the bacterial diversity in desert lake ecosystems.展开更多
Aquatic vegetation(AV)plays a vital role in maintaining lake ecosystem balance and regulating carbon cycling.Accurate estimation of AV coverage or area is crucial for assessing lake stability and carbon sequestration ...Aquatic vegetation(AV)plays a vital role in maintaining lake ecosystem balance and regulating carbon cycling.Accurate estimation of AV coverage or area is crucial for assessing lake stability and carbon sequestration potential.Current satellite-based methods for AV coverage estimation rely on conventional binary classification(presence/absence within pixels),failing to quantify fractional coverage proportions critical for enhancing carbon stock assessment accuracy.To overcome this limitation,this study introduces a novel stepwise upscaling approach that integrates multiscale remote sensing data.By combining unmanned aerial vehicle(UAV),Sentinel-2 multispectral imager,and Landsat 8 operational land imager(OLI)data,we developed the first satellite pixel-scale AV coverage estimation model that accurately quantifies both the AV coverage and area at the pixel level.Initially,a set of coverage samples matched with Sentinel-2 satellite pixels(10 m×10 m)was constructed on the basis of the high-precision AV coverage maps obtained from UAV images.Subsequently,the Sentinel-based model was established on the basis of the samples and corresponding spectral features derived from Sentinel(R^(2)=0.95,RMSE=7.85%,MAE=5.35%).Similarly,we constructed a set of AV coverage samples matching Landsat satellite pixels(30 m×30 m)based on a refined coverage map obtained from the Sentinel-based model.Based on these samples and Landsat 8 OLI spectral features,we developed the Landsat-based model(R^(2)=0.95,RMSE=7.85%,MAE=5.35%).Applying the Landsat-based model,we mapped AV spatiotemporal dynamics in 42 lakes(>50 km^(2))in the middle and lower reaches of the Yangtze River and Huai River basins(MLY-HRB)from 1990 to 2022.The total AV area in 2022 was 4,896.4 km^(2),with increasing trends in MLY and decreasing trends in HRB over 3 decades.AV coverage ranged from 1.18% in Lake Chaohu to 66.43%in Lake Dongting.The satellite pixel-scale model developed in this study demonstrates high accuracy,robustness,and scalability.It is expected to provide a reliable framework for ecosystem carbon sink quantification and carbon sequestration potential assessments in global lakes.展开更多
This study focused on a multi-indicator assessment methodology for governmental environmental auditing of water protection programs. The environmental status of Wuli Lake in China was assessed using the global indicat...This study focused on a multi-indicator assessment methodology for governmental environmental auditing of water protection programs. The environmental status of Wuli Lake in China was assessed using the global indicators （driver-status-response） developed by the Commission on Sustainable Development, and four additional indicators proposed by the author： water quality, pollution load, aquatic ecosystem status, and lake sediment deposition. Various hydrological, chemical, biological and environmental parameters were used to estimate the values of the indicators for assessment of environmental status of the lake based on time series data sets for twenty years. The indicators proposed can be customized to meeting the needs for particular assessment of water protection programs. This method can be used to evaluate the performance of national environmental protection programs and provide technical support for environmental auditors.展开更多
The goal of this project was to design, build, and test a pilot-scale floating modular treatment system for total phosphorus （TP） removal from nutrient-impaired lakes in central Florida, USA. The treatment sys-tem c...The goal of this project was to design, build, and test a pilot-scale floating modular treatment system for total phosphorus （TP） removal from nutrient-impaired lakes in central Florida, USA. The treatment sys-tem consisted of biological and physical-chemical treatment modules. First, investigations of prospective biological and physical-chemical treatment processes in mesocosms and in bench-scale experiments were conducted. Thirteen different mesocosms were constructed with a variety of substrates and combi-nations of macrophytes and tested for TP and orthophosphate （PO4-^3） removal efficiencies and potential areal removal rates. Bench-scale jar tests and column tests of seven types of absorptive media in addition to three commercial resins were conducted in order to test absorptive capacity. Once isolated process testing was complete, a floating island treatment system （FITS） was designed and deployed for eight months in a lake in central Florida. Phosphorus removal efficiencies of the mesocosm systems averaged about 40%-50%, providing an average uptake of 5.0 g.m ^2.a ^1 across all mesocosms. The best-performing mesocosms were a submerged aquatic vegetation （SAV） mesocosm and an algae scrubber （AGS）, which removed 20 and 50 mg.m ^2.d ^1, respectively, for an average removal of 5.5 and 12.0 g.m ^2.a ^1 for the SAV and AGS systems, Of the absorptive media, the best performance was alum residual （AR）, which reduced PO4-^3 concentrations by about 75% after 5 min of contact time. Of the commercial resins tested, the PhosX resin was superior to the others, removing about 40% of phosphorus after 30 rain and 60% after 60min. Under baseline operation conditions during deployment, the FITS exhibited mean PO4-^3 removal efficiencies of 53%; using the 50th and 90th percentile of PO4-^3 removal during deployment, and the footprint of the FITS system, yielded efficiencies for the combined FITS system of 56% and 86%, respectively, and areal phosphorus removal rates between 8.9 and 16.5 g.m ^2.a ^1展开更多
Micro-eukaryotic communities are highly sensitive to environmental changes, and their structure offers crucial insights into the impact of human activities on aquatic habitats. Despite their significance, the assembly...Micro-eukaryotic communities are highly sensitive to environmental changes, and their structure offers crucial insights into the impact of human activities on aquatic habitats. Despite their significance, the assembly mechanisms of micro-eukaryotic communities in lake ecosystems heavily influenced by human activities are not well understood. In this study, we utilized 18S rDNA amplicon sequencing to examine the biodiversity of micro-eukaryotes over a one-year period in Lake Weishan, one of the largest freshwater lakes in northern China. We analyzed the ecological processes governing community assembly among key ecological groups, specifically habitat generalists and specialists. Our findings revealed substantial temporal variation in microbial diversity and community composition, likely driven by water temperature, dissolved oxygen, and the concentrations of several ions (e.g., Ca^(2+) and F^(−)). Notably, community assembly in this canal-disturbed lake was predominantly influenced by stochastic processes (58.18%) rather than deterministic processes (20.46%). Habitat specialists (425 operational taxonomic units, OTUs) exhibited significantly greater diversity compared to habitat generalists (189 OTUs) and were predominantly shaped by stochastic processes (52.47%). In contrast, habitat generalists were less influenced by these processes (17.69%). Altogether, these results suggest that the ecological processes governing micro-eukaryotic community assembly differ markedly between habitat generalists and specialists, primarily due to their varied adaptability to environmental changes.展开更多
Background The impact of vessel-induced waves on macrophyte communities in lakes remains controversial,due to a lack of comprehensive assessments which also consider mechanistic effects on ecological processes during ...Background The impact of vessel-induced waves on macrophyte communities in lakes remains controversial,due to a lack of comprehensive assessments which also consider mechanistic effects on ecological processes during early life stages.This study investigates both the direct and indirect effects of such waves on the early life stages of macrophytes in a case study of Lake W?rthersee,Austria.The study focuses on Characeae species and Najas intermedia which have both experienced significant declines in Lake W?rthersee.Results The linear wave theory was applied to model typical small vessel-induced waves,characterized by wave heights of 0.05–0.30 m and periods of 1 and 3 s.Relevant characteristics for testing remobilization of oospores and seeds like geometric dimensions and density were experimentally determined by field data.Sediment samples from ten locations across six beach sites at depths ranging from 0.8 to 2.2 m were collected and analyzed for oospore presence and sediment texture.Results indicate that maximum wave scenarios can affect oospores and seeds directly by motion activation at water depths down to 3.75 m.Moderate wave scenarios,which are assumed to occur more frequently,can mobilize those particles between 0.75 and 2.25 m water depth.This corresponds to our field data,where 95%of oospores were found in samples from water depths≥2 m.The mobilization disrupts germination processes and impedes the recovery of macrophyte populations.Additionally,in the study lake and other fine-sediment dominated lakes,a significant fraction of sediments can be initiated to motion by small vessel-induced waves,which may indirectly affect germination by altering habitat conditions like turbidity and nutrients.However,grain size distribution showed minimal variation with depth at the same sampling sites,indicating limited sediment redistribution at the selected sampling sites by small vessel-induced waves.No significant correlation was found between oospore abundance and sediment grain size.Conclusions These findings suggest that the impacts of increased traffic of small vessels in lakes may be a key factor contributing to the decline of macrophyte species in shallow waters by motion triggering of oospores and seeds,with broader implications for the recreational management.展开更多
A systematic classification of lakes is essential for effective management,conservation,and scientific research.However,existing approaches often overlook the continuous variability of certain indicators among lakes a...A systematic classification of lakes is essential for effective management,conservation,and scientific research.However,existing approaches often overlook the continuous variability of certain indicators among lakes and are constrained by data availability.In this study,we developed a classification system for 439 lakes larger than 10 km^(2)in China using geomorphological,hydrological,climatic,and landscape features,employing an archetypal analysis approach.Based on the model fitting results,we identified six distinct lake archetypes,which differ from the traditional five classifications based on geographical regions in China.The water quality of lakes across different archetypes responded to a range of geographic,hydrological,meteorological,soil,and anthropogenic factors.Lakes with the highest nutrient levels were predominantly found in Archetypes 5 and 6,located in northeastern China and the Yunnan-Guizhou Plateau,respectively,followed by Archetype 3.In these regions,nutrient levels were strongly associated with human activities.In contrast,indicators such as conductivity and permanganate index in different archetypes were primarily influenced by non-human activities,with the impact of human activities being relatively weak.Phytoplankton,represented by chlorophyll-a,showed a significant response to total phosphorus only in Archetypes 3 and 6,while the response to nitrogen and phosphorus was not significant in the other archetypes.This variation in phytoplankton responses may have been influenced by the climatic conditions in these regions,such as temperature.These findings underscore the importance of developing targeted management and conservation strategies for different lake types,considering their distinct responses to nutrient and temperature changes.Smaller lakes,with relatively simple ecological characteristics,can be managed through targeted strategies tailored to specific types.In contrast,larger lakes require more specialized conservation and management efforts to tackle their complex ecosystem challenges.展开更多
Lakes store 20%of surface freshwater resources and are an important link for studying the interactions between the various spheres of the Earth system[1].There are approximately 1400 lakes larger than 1 km^(2)on the T...Lakes store 20%of surface freshwater resources and are an important link for studying the interactions between the various spheres of the Earth system[1].There are approximately 1400 lakes larger than 1 km^(2)on the Tibetan Plateau(TP),with a total area of approximately 50,000 km^(2),accounting for half of the number and area of lakes in China[2-4].展开更多
文摘Modern hydrobiology,mainly,is based on conception,which may be named Conception of unicity of ecosystem stable state(CUESS):Mature ecosystems are stable and in dynamic equilibrium.Ecosystem state fluctuates around
基金supported by the National Natural Science Foundation of China(Grant Nos.42025707,42171163)。
文摘Lake ecosystems are recognized as“sentinels”of regional climate and environmental change(Loewen,2023).Research over recent decades has established that climate change—through mechanisms such as warming and extreme weather events—significantly impacts lake water quality,biodiversity,and ecological functions(Woolway et al.,2020;Jane et al.,2021).
基金supported by the Universiti Tunku Abdul Rahman under Universiti Research Grant(No.IPSR/RMC/UTARRF/C1-13/G03)
文摘The study of trace metals in the atmosphere and lake water is important due to their critical effects on humans, aquatic animals and the geochemical balance of ecosystems. The objective of this study was to investigate the concentration of trace metals in atmospheric and lake water samples during the rainy season （before and after precipitation） between November and December 2015. Typical methods of sample preparation for trace metal determination such as cloud point extraction, solid phase extraction and dispersive liquid- liquid micro-extraction are time-consuming and difficult to perform; therefore, there is a crucial need for development of more effective sample preparation procedure. A convection microwave assisted digestion procedure for extraction of trace metals was developed for use prior to inductively couple plasma-mass spectrometric determination. The result showed that metals like zinc （133.50-419.30 μg/m3） and aluminum （53.58-378.93 μg/m3） had higher concentrations in atmospheric samples as compared to lake samples before precipitation. On the other hand, the concentrations of zinc, aluminum, chromium and arsenic were significantly higher in lake samples after precipitation and lower in atmospheric samples. The relationship between physicochemical parameters （pH and turbidity） and heavy metal concentrations was investigated as well. Furthermore, enrichment factor analysis indicated that anthropogenic sources such as soil dust, biomass burning and fuel combustion influenced the metal concentrations in the atmosphere.
基金Supported by the National Science and Technology Supporting(No.2012BAD25B08)the Special Fund for Agro-scientific Research in the Public Interest(No.201303056)the Earmarked Fund for China Agriculture Research System(No.CARS-45)
文摘The knowledge of prey small ?sh stock, distribution and abundance is necessary to guide stocking of piscivorous ?sh for the biomanipulation in domestic tap water lakes. This study describes the current status of small ?sh community in Kuilei Lake(China), and examines the spatial and seasonal variations of the community in relation to key environmental factors. Based on submerged macrophyte cover and water depth, the lake was divided into ?ve major habitats:(1) macrophyte covered shallow habitat of water depth< 2.00 m,(2) uncovered or less-covered shallow habitat(2.00 m–3.50 m),(3) uncovered medium shallow habitat(3.50 m–5.00 m),(4) uncovered medium deep habitat(5.00 m–6.50 m) and(5) uncovered deep habitat(6.50 m–8.50 m). The abundance and composition of small ?sh were monitored by benthic fykenet sampling from April 2013 to January 2014. A total of 2881 individuals belonging to 5 families and 21 species were collected. Based on their abundance(accounted for 88.96% of the total) and occurrence(more than 33.33%), Acheilognathus chankaensis, Acheilognathus macropterus, Microphysogobio microstomus,Pseudorasbora parva and Rhinogobius giurinus were recognized as dominant small ?sh species. The results of correlation analysis identi?ed that species richness( Sr), Shannon-Wiener diversity index( H′)and Margalef′s richness index( D) were signi?cantly negatively correlated with water depth, but positively correlated with biomass of submerged macrophytes.Redundancy analysis(RDA) revealed that the spatial distributions of most small ?shes were negatively associated with water depth. The details of these ?ndings are bene?cial to understanding the adaptation of the small ?shes in degraded environments, and to developing suitable biomanipulation strategies for the management of ?sh resources and water quality in the lakes along the lower reach of the Changjiang(Yangtze) River basin.
文摘This paper provides some introductory information on the history, development, and characteristics of various lake ecosystem models. The modeling of lake ecological processes began to gain importance in the early 1960s. There are a number of models available today, with varying levels of complexity to cope with the variety of environmental problems found in lake environments, e.g. eutrophication, acidification, oxygen depletion, wetland management, heavy metal and pesticide pollution, as well as hydrodynamic problems. In particular, this paper focuses on lake eutrophication and wetland models, as well as addressing strategies appropriate for the design and development of reliable lake ecological models.
基金supported by the National Natural Science Foundation of China(Grant Nos.12072261 and 11872305)。
文摘The effects of stochastic perturbations and periodic excitations on the eutrophicated lake ecosystem are explored.Unlike the existing work in detecting early warning signals,this paper presents the most probable transition paths to characterize the regime shifts.The most probable transition paths are obtained by minimizing the Freidlin-Wentzell(FW)action functional and Onsager-Machlup(OM)action functional,respectively.The most probable path shows the movement trend of the lake eutrophication system under noise excitation,and describes the global transition behavior of the system.Under the excitation of Gaussian noise,the results show that the stability of the eutrophic state and the oligotrophic state has different results from two perspectives of potential well and the most probable transition paths.Under the excitation of Gaussian white noise and periodic force,we find that the transition occurs near the nearest distance between the stable periodic solution and the unstable periodic solution.
文摘The presented article discusses the results of survey of the Most lake, which was created within hydric recultivation of the site of the former brown-coal mine Most Lezaky in northern Bohemia in the Czech Republic. The survey discovered plants which belong to ruderal, wetland, halophilic and xerothermal species based on their life strategy. The discovered endangered species include Carex secalina, Schoenoplectus tabaernemontani, Salsola call subsp. Rosacea and Tetragonolobus maritimus. A total of 350 species of vascular plants were discovered in the study area. During the monitoring, a total of 146 bird species were discovered. The monitored location can be currently considered as a significant gathering place namely for aquatic and wetland bird species during the winter period and the migration period （e.g., Tachybaptus ruficollis, Podiceps cristatus, Anser anser, Anas platyrhynchos, Anas strepera, Fulica atra and various species of Larus sp.） and as a significant area of occurrence of relatively rare species bound to anthropogenetically disturbed areas of mining and post-mining landscape （e.g., Anthus campestris, Anthus pratensis, Motacillaflava, Oenanthe oenanthe, Saxicola rubetra and Saxicola torquata）. Within the monitoring of the water quality, the saprobic index values （S） ranged in 2013 between 1.62 and 1.92.
文摘Location & environmental features: Donghu Lake is located at 114°23′ E and 30°33′N in the eastern suburbs of the city of Wuhan, capital of Hubei Province in central China. It is a typical shallow-bottomed, freshwater ecosystem nestling in the middle reaches of the mighty Changjiang (Yangtze) River. With a total surface area of 27.8 square and a mean depth of 2.2 meters, it sprawls in a drainage basin covering an area of 187 square kilometers. The station is situated on the southwest bank of the lake.
基金supported by the National Natural Science Foundation of China(41271265,31570498,31300411)the Science and Technology Projects in Gansu Province(1304NKCA135)the Foundation of China Scholarship Council
文摘Desert lake, a unique oasis in desert ecosystems, harbours different bacterial communities. Thus, it is considered as a hub of bacterial diversity. In this study, bacterial diversity in the sediment of Crescent Moon Spring, Kumtag Desert, Northwest China was analyzed using high-throughput amplicon pyrosequencing analysis. The sequences of the most abundant OUTs （Operational Taxonomic Units） in the sediment of Crescent Moon Spring were compared with the sequences of those most abundant OUTs of various origins from NCBI GenBank database to detect the origins of bacteria in the sediment of Crescent Moon Spring. Also, bacterial compositions between sediment of Crescent Moon Spring and other desert and lake ecosystems （including desert lakes） worldwide were compared using cluster analysis to determine the possible factors affecting bacterial compositions. In total, 11,855 sequences were obtained and 30 phyla were identified. At the phylum level, the dominant phylum was Proteobacteria with α-Proteobacteria being the first dominant class and the second dominant phylum was Planctomycetes. Our finding that α-Proteobacteria being the first dominant class of Proteobacteria and Planctomycetes being the second dominant phyla are somewhat contradictory with reports from other desert lake sediments. This difference could be resulted from water hydration and conductivity, as well as oligotrophic conditions of Crescent Moon Spring. At the genus level, Rhodobacter, Caldilinea, Planctomyces, and Porphyrobacterwere the dominant genera in the sediment of Crescent Moon Spring. Comparisons on sequences of the most abundant OUTs （including OTU3615, OTU6535, and OTU6646） between sediment of Crescent Moon Spring and various origins from NCBI GenBank database indicate that the origins of bacteria in the sediment of Crescent Moon Spring are likely from the underground water. Furthermore, cluster analysis on comparisons of bacteria compositions between sediment of Crescent Moon Spring and other desert and lake ecosystems （including desert lakes） worldwide shows that at regional scales, bacterial compositions may be mainly affected by geographical patterns, precipitation amounts, and pH values. Collectively, our results provide new knowledge on the bacterial diversity in desert lake ecosystems.
基金supported by the National Natural Science Foundation of China(42271377 and 42271114)by Science and Technology Planning Project of NIGLAS(NIGLAS2022GS09).
文摘Aquatic vegetation(AV)plays a vital role in maintaining lake ecosystem balance and regulating carbon cycling.Accurate estimation of AV coverage or area is crucial for assessing lake stability and carbon sequestration potential.Current satellite-based methods for AV coverage estimation rely on conventional binary classification(presence/absence within pixels),failing to quantify fractional coverage proportions critical for enhancing carbon stock assessment accuracy.To overcome this limitation,this study introduces a novel stepwise upscaling approach that integrates multiscale remote sensing data.By combining unmanned aerial vehicle(UAV),Sentinel-2 multispectral imager,and Landsat 8 operational land imager(OLI)data,we developed the first satellite pixel-scale AV coverage estimation model that accurately quantifies both the AV coverage and area at the pixel level.Initially,a set of coverage samples matched with Sentinel-2 satellite pixels(10 m×10 m)was constructed on the basis of the high-precision AV coverage maps obtained from UAV images.Subsequently,the Sentinel-based model was established on the basis of the samples and corresponding spectral features derived from Sentinel(R^(2)=0.95,RMSE=7.85%,MAE=5.35%).Similarly,we constructed a set of AV coverage samples matching Landsat satellite pixels(30 m×30 m)based on a refined coverage map obtained from the Sentinel-based model.Based on these samples and Landsat 8 OLI spectral features,we developed the Landsat-based model(R^(2)=0.95,RMSE=7.85%,MAE=5.35%).Applying the Landsat-based model,we mapped AV spatiotemporal dynamics in 42 lakes(>50 km^(2))in the middle and lower reaches of the Yangtze River and Huai River basins(MLY-HRB)from 1990 to 2022.The total AV area in 2022 was 4,896.4 km^(2),with increasing trends in MLY and decreasing trends in HRB over 3 decades.AV coverage ranged from 1.18% in Lake Chaohu to 66.43%in Lake Dongting.The satellite pixel-scale model developed in this study demonstrates high accuracy,robustness,and scalability.It is expected to provide a reliable framework for ecosystem carbon sink quantification and carbon sequestration potential assessments in global lakes.
基金Project supported by the International Project between The Netherlands Royal Academy of Arts and Sciences and Chinese Academy of Sciences (No. 04CDP014) the National Natural Science Foundation of China (No. 40471130)
文摘This study focused on a multi-indicator assessment methodology for governmental environmental auditing of water protection programs. The environmental status of Wuli Lake in China was assessed using the global indicators （driver-status-response） developed by the Commission on Sustainable Development, and four additional indicators proposed by the author： water quality, pollution load, aquatic ecosystem status, and lake sediment deposition. Various hydrological, chemical, biological and environmental parameters were used to estimate the values of the indicators for assessment of environmental status of the lake based on time series data sets for twenty years. The indicators proposed can be customized to meeting the needs for particular assessment of water protection programs. This method can be used to evaluate the performance of national environmental protection programs and provide technical support for environmental auditors.
基金the Lake Jesup Total Phosphorus Removal Treatment Technologies Floating Island Pilot Project (25104) of St. Johns River Water Management District Palatka+1 种基金 FL USA
文摘The goal of this project was to design, build, and test a pilot-scale floating modular treatment system for total phosphorus （TP） removal from nutrient-impaired lakes in central Florida, USA. The treatment sys-tem consisted of biological and physical-chemical treatment modules. First, investigations of prospective biological and physical-chemical treatment processes in mesocosms and in bench-scale experiments were conducted. Thirteen different mesocosms were constructed with a variety of substrates and combi-nations of macrophytes and tested for TP and orthophosphate （PO4-^3） removal efficiencies and potential areal removal rates. Bench-scale jar tests and column tests of seven types of absorptive media in addition to three commercial resins were conducted in order to test absorptive capacity. Once isolated process testing was complete, a floating island treatment system （FITS） was designed and deployed for eight months in a lake in central Florida. Phosphorus removal efficiencies of the mesocosm systems averaged about 40%-50%, providing an average uptake of 5.0 g.m ^2.a ^1 across all mesocosms. The best-performing mesocosms were a submerged aquatic vegetation （SAV） mesocosm and an algae scrubber （AGS）, which removed 20 and 50 mg.m ^2.d ^1, respectively, for an average removal of 5.5 and 12.0 g.m ^2.a ^1 for the SAV and AGS systems, Of the absorptive media, the best performance was alum residual （AR）, which reduced PO4-^3 concentrations by about 75% after 5 min of contact time. Of the commercial resins tested, the PhosX resin was superior to the others, removing about 40% of phosphorus after 30 rain and 60% after 60min. Under baseline operation conditions during deployment, the FITS exhibited mean PO4-^3 removal efficiencies of 53%; using the 50th and 90th percentile of PO4-^3 removal during deployment, and the footprint of the FITS system, yielded efficiencies for the combined FITS system of 56% and 86%, respectively, and areal phosphorus removal rates between 8.9 and 16.5 g.m ^2.a ^1
基金supported by the National Natural Science Foundation of China(No.32030015,32470545)Science&Technology Fundamental Resources Investigation Program(Grant No.2022FY100400)+1 种基金the Key Projects of Science and Technology Research from the Education Department of Hubei Province(D20221002)the Project(No:RSP2025R7)of the King Saud University,Saudi Arabia.
文摘Micro-eukaryotic communities are highly sensitive to environmental changes, and their structure offers crucial insights into the impact of human activities on aquatic habitats. Despite their significance, the assembly mechanisms of micro-eukaryotic communities in lake ecosystems heavily influenced by human activities are not well understood. In this study, we utilized 18S rDNA amplicon sequencing to examine the biodiversity of micro-eukaryotes over a one-year period in Lake Weishan, one of the largest freshwater lakes in northern China. We analyzed the ecological processes governing community assembly among key ecological groups, specifically habitat generalists and specialists. Our findings revealed substantial temporal variation in microbial diversity and community composition, likely driven by water temperature, dissolved oxygen, and the concentrations of several ions (e.g., Ca^(2+) and F^(−)). Notably, community assembly in this canal-disturbed lake was predominantly influenced by stochastic processes (58.18%) rather than deterministic processes (20.46%). Habitat specialists (425 operational taxonomic units, OTUs) exhibited significantly greater diversity compared to habitat generalists (189 OTUs) and were predominantly shaped by stochastic processes (52.47%). In contrast, habitat generalists were less influenced by these processes (17.69%). Altogether, these results suggest that the ecological processes governing micro-eukaryotic community assembly differ markedly between habitat generalists and specialists, primarily due to their varied adaptability to environmental changes.
基金a Project(WAMOS)funded by the Austrian Promotion Agency(FFG)within the program line“ASAP”(Project Number FO999900575)
文摘Background The impact of vessel-induced waves on macrophyte communities in lakes remains controversial,due to a lack of comprehensive assessments which also consider mechanistic effects on ecological processes during early life stages.This study investigates both the direct and indirect effects of such waves on the early life stages of macrophytes in a case study of Lake W?rthersee,Austria.The study focuses on Characeae species and Najas intermedia which have both experienced significant declines in Lake W?rthersee.Results The linear wave theory was applied to model typical small vessel-induced waves,characterized by wave heights of 0.05–0.30 m and periods of 1 and 3 s.Relevant characteristics for testing remobilization of oospores and seeds like geometric dimensions and density were experimentally determined by field data.Sediment samples from ten locations across six beach sites at depths ranging from 0.8 to 2.2 m were collected and analyzed for oospore presence and sediment texture.Results indicate that maximum wave scenarios can affect oospores and seeds directly by motion activation at water depths down to 3.75 m.Moderate wave scenarios,which are assumed to occur more frequently,can mobilize those particles between 0.75 and 2.25 m water depth.This corresponds to our field data,where 95%of oospores were found in samples from water depths≥2 m.The mobilization disrupts germination processes and impedes the recovery of macrophyte populations.Additionally,in the study lake and other fine-sediment dominated lakes,a significant fraction of sediments can be initiated to motion by small vessel-induced waves,which may indirectly affect germination by altering habitat conditions like turbidity and nutrients.However,grain size distribution showed minimal variation with depth at the same sampling sites,indicating limited sediment redistribution at the selected sampling sites by small vessel-induced waves.No significant correlation was found between oospore abundance and sediment grain size.Conclusions These findings suggest that the impacts of increased traffic of small vessels in lakes may be a key factor contributing to the decline of macrophyte species in shallow waters by motion triggering of oospores and seeds,with broader implications for the recreational management.
基金supported by the National Natural Science Foundation of China(Grant Nos.42025707,32171546)the Third Comprehensive Scientific Investigation Project of Xinjiang(Grant No.2022xjkk1504)+1 种基金the Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0202)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20231516)。
文摘A systematic classification of lakes is essential for effective management,conservation,and scientific research.However,existing approaches often overlook the continuous variability of certain indicators among lakes and are constrained by data availability.In this study,we developed a classification system for 439 lakes larger than 10 km^(2)in China using geomorphological,hydrological,climatic,and landscape features,employing an archetypal analysis approach.Based on the model fitting results,we identified six distinct lake archetypes,which differ from the traditional five classifications based on geographical regions in China.The water quality of lakes across different archetypes responded to a range of geographic,hydrological,meteorological,soil,and anthropogenic factors.Lakes with the highest nutrient levels were predominantly found in Archetypes 5 and 6,located in northeastern China and the Yunnan-Guizhou Plateau,respectively,followed by Archetype 3.In these regions,nutrient levels were strongly associated with human activities.In contrast,indicators such as conductivity and permanganate index in different archetypes were primarily influenced by non-human activities,with the impact of human activities being relatively weak.Phytoplankton,represented by chlorophyll-a,showed a significant response to total phosphorus only in Archetypes 3 and 6,while the response to nitrogen and phosphorus was not significant in the other archetypes.This variation in phytoplankton responses may have been influenced by the climatic conditions in these regions,such as temperature.These findings underscore the importance of developing targeted management and conservation strategies for different lake types,considering their distinct responses to nutrient and temperature changes.Smaller lakes,with relatively simple ecological characteristics,can be managed through targeted strategies tailored to specific types.In contrast,larger lakes require more specialized conservation and management efforts to tackle their complex ecosystem challenges.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0206)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA20100300)+3 种基金the National Natural Science Foundation of China(42205176)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2021073)the National Key Scientific and Technological Infrastructure Project“Earth System Science Numerical Simulator Facility”(EarthLab)the Open Fund Project of Key Lab of Virtual Geographic Environment(Nanjing Normal University),Ministry of Education(2021VGE04).
文摘Lakes store 20%of surface freshwater resources and are an important link for studying the interactions between the various spheres of the Earth system[1].There are approximately 1400 lakes larger than 1 km^(2)on the Tibetan Plateau(TP),with a total area of approximately 50,000 km^(2),accounting for half of the number and area of lakes in China[2-4].
