Study On Effects Of Increased Temperature And Precipitation Change On Denitrifying Bacterial Communities In Alpine Meadow Soils On The Qinghai-Tibet Plateau0

Globally,climate change has become one of the most studied research topics.The Qinghai-Tibet plateau represents a typical ecologically fragile zone and has been experiencing rapid warming and precipitation change.Climate change has resulted in massive glacier melting and hydrology cycling change on the plateau.The present study explored the effects of the warming(1?2?4?)and altered precipitation(double precipitation?half of precipitation)for 1?3?13 months on the denitrifying bacterial community in alpine meadow soils at Naqu research station on the Qinghai-Tibet plateau.The effects of warming and precipitation change on denitrifying bacteria(nirK,nirS,nosZ)abundance,community structure and diversity were characterized using quantitative polymerase chain reaction(qPCR),terminal restriction fragment length polymorphism(T-RFLP).The results showed that nirS and nosZ copies were 10 times of nirK.Temperature increase,altered precipitation and both together did not significantly affect nirK,nirS and nosZ gene abundances.Sampling time affected the abundances of nosZ rather than nirK and nirS.More apparent response of nirS and nosZ denitrifying bacteria community structure to temperature and precipitation changes than nirK denitrifying bacteria.The community structure of nirS and nos Z denitrifying bacteria have more obvious change when the warming continued for 1 month but not nirK,and the latter one changed gradually with the warming treatment time.We also found that there was interaction of warming and precipitation alteration on nirK,nirS and nosZ community structure.Compared with 2 ? warming treatment and 100% precipitation increase treatment,the sampling time exerted a much stronger influence on community structures of nirK,nirS and nosZ denitrifying bacteria.Community structures of nirK,nirS and nosZ respond to sampling time was regulated by warming and precipitation alteration.As to nirK and nirS community structures,sampling time influences was regulated by 100% precipitation increase more significantly than 2 ? warming,but nosZ was sensitive to regulation of both 100% precipitation increase and 2 ? warming.Warming and altered precipitation had no significant effect on the diversity of nir K,nir S and nosZ denitrifying bacteria,and there was no significant difference between different sampling times.