title: Comparative bioavailability of ammonium, nitrate, nitrite and urea to typically harmful cyanobacterium Microcystis aeruginosa.
abstract: Phosphorus is generally considered as the prime limiting nutrient responsible for cyanobacterial blooms. However, recent research is drawing attention to the importance of bioavailable nitrogen (N) in freshwater eutrophication. This study investigated the bioavailability of NO3(-)-N, NO2(-)-N, NH4(+)-N and Urea-N under different concentrations of 1.2, 3.6 and 6.0mgL(-1) to Microcystis aeruginosa. Overall, Urea-N ranked the first in promoting M. aeruginosa growth, followed by NO3(-)-N and NO2(-)-N. However, the algal growth cultured in NH4(+)-N was depressed under test N levels. The bioavailability of N to M. aeruginosa was seriously influenced by both N forms and N concentrations (p<0.01). Total N concentrations in Urea-N treatment decreased the fastest, which were corresponding with the μ values of M. aeruginosa. The high enzymic activities of nitrate reductase, nitrite reductase and glutamine synthetase indicated that the decomposition process for urea is effective, which contributed in N assimilation and utilization in M. aeruginosa cells.
authors.affiliation: College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, PR China; Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, PR China.
authors.forename: Jihua
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, PR China.
authors.forename: Jibiao
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.affiliation: College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, PR China.
authors.forename: Fanlong
authors.initials: F
authors.lastname: Kong
authors.affiliation: College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, PR China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Li
authors.affiliation: College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, PR China. Electronic address: ximin2008@126.com.
authors.forename: Min
authors.initials: M
authors.lastname: Xi
authors.affiliation: Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, PR China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Zheng
mesh_terms: D064751:Ammonium Compounds; D001682:Biological Availability; D005068:Eutrophication; D005618:Fresh Water; D046931:Microcystis / Q000378:metabolism*; D009573:Nitrites; D014508:Urea
chemical_list: D064751:Ammonium Compounds; D009573:Nitrites; D014508:Urea
keywords: Glutamine synthetase; Microcystis aeruginosa; Nitrate reductase; Nitrite reductase; Nitrogen utilization