Two ecotypes of Elsholtzia, Elsholtzia splendens and E. argyi, are dominantplants growing on Cu and Pb-Zn smelters, respectively. Samples of the two ecotypes and thecorresponding soils from fields of a copper mining a...Two ecotypes of Elsholtzia, Elsholtzia splendens and E. argyi, are dominantplants growing on Cu and Pb-Zn smelters, respectively. Samples of the two ecotypes and thecorresponding soils from fields of a copper mining area and a Pb-Zn mining area ofZhejiang Province,China, were analyzed to investigate Cu or Zn tolerance of these two ecotypes. Effects of nine Culevels (0, 5, 10, 20, 40, 80, 160, 240 and 320 mg Cu L^(-1) as CuSO_4 centre dot 5H_O) on growth anduptake, translocation and accumulation of Cu in these two ecotypes were examined in a solutionculture experiment. The experimental results showed that dry weights (DW) of shoots and roots weredepressed, and growth of E. splendens was less depressed than that of E. argyi when treated with>= 5mg Cu L^(-1). Concentrations of Cu in shoots of E. splendens and E. argyi exceeded 1000 mg kg^(-1)DW at >= 40 mg Cu L^(-1). The maximum Cu accumulated in the shoots of Cu-treated E. splendens and E.argyi reached 101 and 142 mu g plant^(-1). Furthermore, analysis of plant samples from the fieldsshowed that these two ecotypes can tolerant excess heavy metals and produced high dry matter, and E.splendens can accumulate 11.7 mg Cu plant^(-1) grown on the Cu smelter. Therefore, E. splendens andE.argyi could be good plants for phytoremediation.展开更多
The spatial distribution pattern of organisms is a basic issue in understanding the mechanisms of community assembly. Although the spatial distributions of animals and plants have been well studied,those of microorgan...The spatial distribution pattern of organisms is a basic issue in understanding the mechanisms of community assembly. Although the spatial distributions of animals and plants have been well studied,those of microorganisms are still being debated. In this study, we used a fi sh gut microecosystem to detect the spatial pattern of microbes, because it can provide a relatively unifi ed and stable environment. Results suggest that the turnover of intestinal bacterial assemblages showed a weak but highly signifi cant negative correlation between similarity and distances in the microbial community, in respect of both grass carp intestinal loci distances and the geographical distance between fi sh sampling sites. Our results also suggest that intestinal bacterial assemblages responded to differences within the external environment and within different parts of the fi sh themselves. These results show that some, or possibly all, microbes are restricted in their distribution and that environmental factors are also important infl uences on the structure of intestinal bacterial assemblages. The fi sh gut microecosystem is useful in promoting study of the spatial distribution patterns of microorganisms.展开更多
This paper is to establish a nitrogen and phosphorus nutrients cycle-based numerical model of ecological dynamics for Xiamen Bay on the basis of the existing three-dimensional barocline hydrodynamic model. The calcula...This paper is to establish a nitrogen and phosphorus nutrients cycle-based numerical model of ecological dynamics for Xiamen Bay on the basis of the existing three-dimensional barocline hydrodynamic model. The calculation results show that the estuarine district of Jiulongjiang estuary has the highest inorganic nitrogen concentration followed by the West Harbor, which demonstrates that Jiulongjiang River is the main input source of inorganic nitrogen in Xiamen Bay. The West Harbor has relatively high concentration of nutrients caused by the huge land pollution emission and its own poor water exchange capacity; while the distribution rules of phytoplankton biomass correspond with those of phosphates, demonstrating Xiamen Bay＇s phytoplankton controlled by phosphorus; the haloplankton biomass differs slightly, presenting the gradual reduction from the interior part to the exterior part of the bay.展开更多
Anchovy （Engraulis aponicus）, a small pelagic fish and food of other economic fishes, is a key species in the Yellow Sea ecosystem. Understanding the mechanisms of its recruitment and biomass variation is important ...Anchovy （Engraulis aponicus）, a small pelagic fish and food of other economic fishes, is a key species in the Yellow Sea ecosystem. Understanding the mechanisms of its recruitment and biomass variation is important for the prediction and management of fishery resources. Coupled with a hydrodynamic model （POM） and a lower trophic level ecosystem model （NEMURO）, an individual-based model of anchovy is developed to study the influence of physical environment on anchovy＇s biomass variation, Seasonal variations of circulation, water temperature and mix-layer depth from POM are used as external forcing for NEMURO and the anchovy model. Biomasses of large zooplankton and predatory zooplankton which anchovy feeds on are output from NEMURO and are controlled by the consumption of anchovy on them. Survival fitness theory related to temperature and food is used to determine the swimming action of anchovy in the model. The simulation results agree well with observations and elucidate the influence of temperature in over-wintering migration and food in feeding migration.展开更多
Shifts in the realized niches of exotic species may play an important role in their invasion.Galinsoga quadriradiata has invaded China widely and occupied many climate zones that are different from its native range.We...Shifts in the realized niches of exotic species may play an important role in their invasion.Galinsoga quadriradiata has invaded China widely and occupied many climate zones that are different from its native range.We addressed the climatic niche shift of G.quadriradiata and evaluated how this could contribute to its invasion in China.We used the Maxent model to predict the potential distribution of G.quadriradiata using its native and invaded range occurrences and climatic variables.Principal component analysis was conducted to measure climatic niche shifts of G.quadriradiata during its invasion in China.The models revealed only 32.7%niche overlap between the native and invasive populations.The niche similarity of the two populations was significantly low(Schoener’s D=0.093,P<0.005),suggesting the occurrence of a niche shift.The envelop and center of the realized climatic niche in China has shifted to lower temperature and less precipitation compared to that in its native range.The majority of invaded areas in southern China are in the stabilizing zone,whereas the colonization and adaptation zones are predicted to be at the leading edge of G.quadriradiata invasion in northern China.This suggests that the regional distribution of G.quadriradiata may be in a quasi-equilibrium state,and that the species continues to invade environmentally suitable areas.Alterations in G.quadriradiata’s niche would help to explain why this species is so invasive in China.展开更多
A mathematical model describing the dynamics of toxin producing phytoplankton- zooplankton interaction with instantaneous nutrient recycling is proposed. We have explored the dynamics of plankton ecosystem with multip...A mathematical model describing the dynamics of toxin producing phytoplankton- zooplankton interaction with instantaneous nutrient recycling is proposed. We have explored the dynamics of plankton ecosystem with multiple delays; one due to gestation period in the growth of phytoplankton population and second due to the delay in toxin liberated by TPP. It is established that a sequence of Hopf bifurcations occurs at the interior equilibrium as the delay increases through its critical value. The direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions are determined using the theory of normal form and center manifold. Meanwhile, effect of toxin on the stability of delayed plankton system is also established numerically. Finally, numerical simulations are carried out to support and supplement the analytical findings.展开更多
Identifying the causes of diversification is central to evolutionary biology. The ecological theory of adaptive diversi- fication holds that the evolution of phenotypic differences between populations and species--and...Identifying the causes of diversification is central to evolutionary biology. The ecological theory of adaptive diversi- fication holds that the evolution of phenotypic differences between populations and species--and the formation of new spe- cies-stems from divergent natural selection, often arising from competitive interactions. Although increasing evidence suggests that phenotypic plasticity can facilitate this process, it is not generally appreciated that competitively mediated selection often also provides ideal conditions for phenotypic plasticity to evolve in the first place. Here, we discuss how competition plays at least two key roles in adaptive diversification depending on its pattern. First, heterogenous competition initially generates heterogeneity in resource use that favors adaptive plasticity in the form of ＂inducible competitors＂. Second, once such competitively induced plas- ticity evolves, its capacity to rapidly generate phenotypic variation and expose phenotypes to alternate selective regimes allows populations to respond readily to selection favoring diversification, as may occur when competition generates steady diversifying selection that permanently drives the evolutionary divergence of populations that use different resources. Thus, competition plays two important roles in adaptive diversification---one well-known and the other only now emerging--mediated through its effect on the evolution ofphenotypic plasticity展开更多
基金Project supported by the National Natural Science Foundation of China (No. 29977017)
文摘Two ecotypes of Elsholtzia, Elsholtzia splendens and E. argyi, are dominantplants growing on Cu and Pb-Zn smelters, respectively. Samples of the two ecotypes and thecorresponding soils from fields of a copper mining area and a Pb-Zn mining area ofZhejiang Province,China, were analyzed to investigate Cu or Zn tolerance of these two ecotypes. Effects of nine Culevels (0, 5, 10, 20, 40, 80, 160, 240 and 320 mg Cu L^(-1) as CuSO_4 centre dot 5H_O) on growth anduptake, translocation and accumulation of Cu in these two ecotypes were examined in a solutionculture experiment. The experimental results showed that dry weights (DW) of shoots and roots weredepressed, and growth of E. splendens was less depressed than that of E. argyi when treated with>= 5mg Cu L^(-1). Concentrations of Cu in shoots of E. splendens and E. argyi exceeded 1000 mg kg^(-1)DW at >= 40 mg Cu L^(-1). The maximum Cu accumulated in the shoots of Cu-treated E. splendens and E.argyi reached 101 and 142 mu g plant^(-1). Furthermore, analysis of plant samples from the fieldsshowed that these two ecotypes can tolerant excess heavy metals and produced high dry matter, and E.splendens can accumulate 11.7 mg Cu plant^(-1) grown on the Cu smelter. Therefore, E. splendens andE.argyi could be good plants for phytoremediation.
基金Supported by the National Basic Research Program of China(973 Program)(No.2009CB118705)the National Natural Science Foundation of China(Nos.30970358,31071896)the Youth Innovation Promotion Association,CAS
文摘The spatial distribution pattern of organisms is a basic issue in understanding the mechanisms of community assembly. Although the spatial distributions of animals and plants have been well studied,those of microorganisms are still being debated. In this study, we used a fi sh gut microecosystem to detect the spatial pattern of microbes, because it can provide a relatively unifi ed and stable environment. Results suggest that the turnover of intestinal bacterial assemblages showed a weak but highly signifi cant negative correlation between similarity and distances in the microbial community, in respect of both grass carp intestinal loci distances and the geographical distance between fi sh sampling sites. Our results also suggest that intestinal bacterial assemblages responded to differences within the external environment and within different parts of the fi sh themselves. These results show that some, or possibly all, microbes are restricted in their distribution and that environmental factors are also important infl uences on the structure of intestinal bacterial assemblages. The fi sh gut microecosystem is useful in promoting study of the spatial distribution patterns of microorganisms.
文摘This paper is to establish a nitrogen and phosphorus nutrients cycle-based numerical model of ecological dynamics for Xiamen Bay on the basis of the existing three-dimensional barocline hydrodynamic model. The calculation results show that the estuarine district of Jiulongjiang estuary has the highest inorganic nitrogen concentration followed by the West Harbor, which demonstrates that Jiulongjiang River is the main input source of inorganic nitrogen in Xiamen Bay. The West Harbor has relatively high concentration of nutrients caused by the huge land pollution emission and its own poor water exchange capacity; while the distribution rules of phytoplankton biomass correspond with those of phosphates, demonstrating Xiamen Bay＇s phytoplankton controlled by phosphorus; the haloplankton biomass differs slightly, presenting the gradual reduction from the interior part to the exterior part of the bay.
基金supported by the National Natural Science Foundation of China (Grant No. 40830854)the National Basic Research Program of China (Grant No.2011CB403606)
文摘Anchovy （Engraulis aponicus）, a small pelagic fish and food of other economic fishes, is a key species in the Yellow Sea ecosystem. Understanding the mechanisms of its recruitment and biomass variation is important for the prediction and management of fishery resources. Coupled with a hydrodynamic model （POM） and a lower trophic level ecosystem model （NEMURO）, an individual-based model of anchovy is developed to study the influence of physical environment on anchovy＇s biomass variation, Seasonal variations of circulation, water temperature and mix-layer depth from POM are used as external forcing for NEMURO and the anchovy model. Biomasses of large zooplankton and predatory zooplankton which anchovy feeds on are output from NEMURO and are controlled by the consumption of anchovy on them. Survival fitness theory related to temperature and food is used to determine the swimming action of anchovy in the model. The simulation results agree well with observations and elucidate the influence of temperature in over-wintering migration and food in feeding migration.
基金supported by the National Natural Science Foundation of China(32071520,31600445 and 31570425)the Natural Science Basic Research Plan in Shaanxi Province of China(2020JM-286)+2 种基金the Central University Innovation Team Project(GK202001006)the Fundamental Research Funds for the Central Universities(GK202103072 and 2020CSLY014)the Research Funds of Shaanxi Association for Science and Technology,and the Research Funds of Xi’an Association for Science and Technology(202113).
文摘Shifts in the realized niches of exotic species may play an important role in their invasion.Galinsoga quadriradiata has invaded China widely and occupied many climate zones that are different from its native range.We addressed the climatic niche shift of G.quadriradiata and evaluated how this could contribute to its invasion in China.We used the Maxent model to predict the potential distribution of G.quadriradiata using its native and invaded range occurrences and climatic variables.Principal component analysis was conducted to measure climatic niche shifts of G.quadriradiata during its invasion in China.The models revealed only 32.7%niche overlap between the native and invasive populations.The niche similarity of the two populations was significantly low(Schoener’s D=0.093,P<0.005),suggesting the occurrence of a niche shift.The envelop and center of the realized climatic niche in China has shifted to lower temperature and less precipitation compared to that in its native range.The majority of invaded areas in southern China are in the stabilizing zone,whereas the colonization and adaptation zones are predicted to be at the leading edge of G.quadriradiata invasion in northern China.This suggests that the regional distribution of G.quadriradiata may be in a quasi-equilibrium state,and that the species continues to invade environmentally suitable areas.Alterations in G.quadriradiata’s niche would help to explain why this species is so invasive in China.
文摘A mathematical model describing the dynamics of toxin producing phytoplankton- zooplankton interaction with instantaneous nutrient recycling is proposed. We have explored the dynamics of plankton ecosystem with multiple delays; one due to gestation period in the growth of phytoplankton population and second due to the delay in toxin liberated by TPP. It is established that a sequence of Hopf bifurcations occurs at the interior equilibrium as the delay increases through its critical value. The direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions are determined using the theory of normal form and center manifold. Meanwhile, effect of toxin on the stability of delayed plankton system is also established numerically. Finally, numerical simulations are carried out to support and supplement the analytical findings.
基金Acknowledgements We thank Zhi-Yun Jia for inviting us to submit this paper to a special column on phenotypic plasticity. Three anonymous reviewers provided valuable commentary that encouraged us to improve this work. We also wish to ac- knowledge the long term funding for plasticity research pro- vided by the U.S. National Science Foundation to DP, and the Natural Sciences and Engineering Research Council of Can- ada to BR. Finally, collaboration on this specific project was directly supported through a short-term fellowship to BR by the National Evolutionary Synthesis Center （NESCent funded by NSF #EF-0905606）.
文摘Identifying the causes of diversification is central to evolutionary biology. The ecological theory of adaptive diversi- fication holds that the evolution of phenotypic differences between populations and species--and the formation of new spe- cies-stems from divergent natural selection, often arising from competitive interactions. Although increasing evidence suggests that phenotypic plasticity can facilitate this process, it is not generally appreciated that competitively mediated selection often also provides ideal conditions for phenotypic plasticity to evolve in the first place. Here, we discuss how competition plays at least two key roles in adaptive diversification depending on its pattern. First, heterogenous competition initially generates heterogeneity in resource use that favors adaptive plasticity in the form of ＂inducible competitors＂. Second, once such competitively induced plas- ticity evolves, its capacity to rapidly generate phenotypic variation and expose phenotypes to alternate selective regimes allows populations to respond readily to selection favoring diversification, as may occur when competition generates steady diversifying selection that permanently drives the evolutionary divergence of populations that use different resources. Thus, competition plays two important roles in adaptive diversification---one well-known and the other only now emerging--mediated through its effect on the evolution ofphenotypic plasticity
