Meromictic soda and saline lakes are unique ecosystems characterized by the stability of physical,chemical and biological parameters,and they are distributed all over the world.Lakes located in regions with average an...Meromictic soda and saline lakes are unique ecosystems characterized by the stability of physical,chemical and biological parameters,and they are distributed all over the world.Lakes located in regions with average annual negative air temperature are of particular interest because of the presence of two periods with intensive and dynamic processes:the so-called biological summer and the long ice season with the biological spring.Soda Lake Doroninskoe is located in Eastern Transbaikalia(51°14′N,112°14′E) in the permafrost zone in an extreme continental climate,and is covered by ice for seven months per year.The structure and diversity of the microbial communities throughout the water column of the lake was studied by 16 S r RNA gene amplicon metasequencing.Different species with specific functions were found to dominate at different depths.Metabolically flexible bacteria with a capacity to switch between anoxygenic photosynthesis and aerobic chemotrophic metabolism dominate in soda Lake Doroninskoe.展开更多
The community structure of adult mosquitoes was compared from New Jerseylight trap collections in six different types of habitats in Citrus County, Florida, USA. FromOctober 1998 to December 2000, mosquitoes were coll...The community structure of adult mosquitoes was compared from New Jerseylight trap collections in six different types of habitats in Citrus County, Florida, USA. FromOctober 1998 to December 2000, mosquitoes were collected three times a week from the followinghabitats (swamps, swamps and freshwater marshes, pine flatwoods, pine flatwoods and scrub, saltmarshes, and salt marshes and mangroves). Mosquito density was highest in the swamps and freshwatermarshes habitat, with an average of 95.65 specimens per trap. Density was lowest in the flatwoodsand scrub habitat, with an average of 14.38 specimens per trap. Species dominance differed amonghabitats. Salt marshes produced the greatest aggregation index, while pine flatwoods produced thelowest. Conversely, diversity analysis showed that pine flatwoods had the greatest diversity, whilesalt marshes the lowest diversity. Similarity indices indicated that the adult mosquito communitiesfrom pine flatwoods and pine flatwoods and scrub were very similar (0.8583). The adult mosquitocommunity of salt marshes was different from that of swamps and freshwater marshes (the similarindex was 0.0217).展开更多
Aims The effects of biocrusts on vascular plants are rarely evaluated in coastal saline lands.Our aim was to examine whether and how a mosaic of biocrusts affect seed germination of two typical herbaceous plants in a ...Aims The effects of biocrusts on vascular plants are rarely evaluated in coastal saline lands.Our aim was to examine whether and how a mosaic of biocrusts affect seed germination of two typical herbaceous plants in a coastal saline land of the Yellow River Delta,to enhance our understanding by which substrate heterogeneity influences plant community dynamics.Methods We conducted growth chamber experiments to investigate the effects of biocrusts and uncrusted soil from bare patch-,Phragmites australis-,Suaeda glauca-and Tamarix chinensis-dominated habitats on seed germination percentage and mean germination time of two herbaceous plants:the perennial P.australis and the annual S.glauca.We also explored the mechanisms underlying the effects of substrate on seed germination.Important Findings Compared with uncrusted soil,biocrusts increased water content,nutrient accumulation and concentration of most salt ions,but they reduced soil pH value.Biocrusts with mosses directly decreased soil pH value and concentration of Mg2+,resulting in an indirect increase in seed germination percentage of S.glaucas.The low soil pH value also resulted in an indirect decrease in seed germination speed of P.australis in their own habitats.Bare patch directly increased accumulation of Cl?,resulting in an indirect decrease in seed germination speed of P.australis.These results suggest that biocrusts with mosses in P.australis habitats offer a window of opportunity for germination of S.glaucas.Biocrusts combined with habitat type have the potential to influence plant community structure through an effect on seed germination and establishment.展开更多
文摘Meromictic soda and saline lakes are unique ecosystems characterized by the stability of physical,chemical and biological parameters,and they are distributed all over the world.Lakes located in regions with average annual negative air temperature are of particular interest because of the presence of two periods with intensive and dynamic processes:the so-called biological summer and the long ice season with the biological spring.Soda Lake Doroninskoe is located in Eastern Transbaikalia(51°14′N,112°14′E) in the permafrost zone in an extreme continental climate,and is covered by ice for seven months per year.The structure and diversity of the microbial communities throughout the water column of the lake was studied by 16 S r RNA gene amplicon metasequencing.Different species with specific functions were found to dominate at different depths.Metabolically flexible bacteria with a capacity to switch between anoxygenic photosynthesis and aerobic chemotrophic metabolism dominate in soda Lake Doroninskoe.
文摘The community structure of adult mosquitoes was compared from New Jerseylight trap collections in six different types of habitats in Citrus County, Florida, USA. FromOctober 1998 to December 2000, mosquitoes were collected three times a week from the followinghabitats (swamps, swamps and freshwater marshes, pine flatwoods, pine flatwoods and scrub, saltmarshes, and salt marshes and mangroves). Mosquito density was highest in the swamps and freshwatermarshes habitat, with an average of 95.65 specimens per trap. Density was lowest in the flatwoodsand scrub habitat, with an average of 14.38 specimens per trap. Species dominance differed amonghabitats. Salt marshes produced the greatest aggregation index, while pine flatwoods produced thelowest. Conversely, diversity analysis showed that pine flatwoods had the greatest diversity, whilesalt marshes the lowest diversity. Similarity indices indicated that the adult mosquito communitiesfrom pine flatwoods and pine flatwoods and scrub were very similar (0.8583). The adult mosquitocommunity of salt marshes was different from that of swamps and freshwater marshes (the similarindex was 0.0217).
基金This research was supported by the Joint Funds of the National Natural Science Foundation of China(U2006215)the Natural Science Foundation of Shandong Province(ZR2019PDO08,ZR2020MDOO7)+1 种基金the National Nature Science Foundation of China(41971126)Taishan Scholars Program of Shandong Province,China(TSQN201909152).
文摘Aims The effects of biocrusts on vascular plants are rarely evaluated in coastal saline lands.Our aim was to examine whether and how a mosaic of biocrusts affect seed germination of two typical herbaceous plants in a coastal saline land of the Yellow River Delta,to enhance our understanding by which substrate heterogeneity influences plant community dynamics.Methods We conducted growth chamber experiments to investigate the effects of biocrusts and uncrusted soil from bare patch-,Phragmites australis-,Suaeda glauca-and Tamarix chinensis-dominated habitats on seed germination percentage and mean germination time of two herbaceous plants:the perennial P.australis and the annual S.glauca.We also explored the mechanisms underlying the effects of substrate on seed germination.Important Findings Compared with uncrusted soil,biocrusts increased water content,nutrient accumulation and concentration of most salt ions,but they reduced soil pH value.Biocrusts with mosses directly decreased soil pH value and concentration of Mg2+,resulting in an indirect increase in seed germination percentage of S.glaucas.The low soil pH value also resulted in an indirect decrease in seed germination speed of P.australis in their own habitats.Bare patch directly increased accumulation of Cl?,resulting in an indirect decrease in seed germination speed of P.australis.These results suggest that biocrusts with mosses in P.australis habitats offer a window of opportunity for germination of S.glaucas.Biocrusts combined with habitat type have the potential to influence plant community structure through an effect on seed germination and establishment.
