title: [Nitrifying bacteria and nitrification in sediment at the adjacent sea area of Yangtze River Estuary in summer].
abstract: The influence factors and environmental effects of nitrification process were discussed based on the measurements of nitrifier quantities and nitrification rates at eight sites off Yangtze River Estuary in June 2006. Using FISH (Fluorescence in situ hybridization) method, the nitrifying bacteria were counted as 1.87 x 10(5) -3.53 x 10(5) cells/g wet weight and exhibited salt tolerance to some extent. The nitrification rates, measured by acetylene inhibition technique, ranged from 101.3 to 514.3 micromol/(m2 x h) and had a decreased gradient from nearshore to offshore sediment with two high value regions located at the mouth of Yangtze River and Hangzhou Bay respectively. The nitrifier quantity was a main factor to effect nitrification rates at high-salinity sea area, with an influence ratio of 87.7%. Fluxes of transformed nitrogen and consumed oxygen by nitrification process were 4.68 x 10(5) kg and 6.07 x 10(4) mol per day respectively, suggesting that nitrification would be an important factor for the distribution of DIN species and DO at bottom water in early summer.
authors.affiliation: Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, College of Environmental Science and Engineering Ocean University of China, Qingdao 266100, China. selenajulian@163.com
authors.forename: Jia-Lin
authors.initials: JL
authors.lastname: Li
authors.forename: Jie
authors.initials: J
authors.lastname: Bai
authors.forename: Hui-Wang
authors.initials: HW
authors.lastname: Gao
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Wang
authors.forename: Lei-Lei
authors.initials: LL
authors.lastname: Sheng
mesh_terms: D000641:Ammonia / Q000378:metabolism; D002681:China; D019015:Geologic Sediments / Q000382:microbiology*; D009576:Nitrobacter / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D009792:Oceans and Seas; D045483:Rivers; D054712:Salinity; D012621:Seasons; D012623:Seawater / Q000382:microbiology; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D014874:Water Pollutants, Chemical; D000641:Ammonia; D009584:Nitrogen