title: The relationship between light intensity and nutrient uptake kinetics in six freshwater diatoms.
abstract: In order to find effective measures to control diatom blooms, a better understanding of the physiological characteristics of nutrient uptake in diatoms is needed. A study of P and Si-uptake kinetics for diatom species from two light regimes was conducted at low (LL), moderate (ML) and high light intensities (HL) (2, 25 and 80 μmol photons/(m(2)·sec)), respectively. The results showed that P uptake of diatoms was heavily influenced by historic light regimes. P affinity changed with growth and photosynthetic activity. The lowest half saturation constant for P uptake (Km(P)) was under HL for high-light adapted diatoms while the lowest half-saturation constant for low-light adapted diatoms was observed under LL. The Si half-saturation constant (Km(Si)) increased with increasing light intensities for pennate diatoms but decreased for centric diatoms. Diatom volumes were correlated with the maximum Si uptake rates (Vm(Si)) at HL and Km(Si) at ML and HL for six diatom species. Our results imply that when we assess the development of diatom blooms we should consider light intensity and cell volume in addition to ambient Si or P concentration. The relationship between light intensity and P-uptake suggests that we can find suitable methods to control diatom blooms on the basis of reducing phytoplankton activity of P-uptake and photosynthesis simultaneously.
authors.affiliation: College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China. Electronic address: jasmine642469@hotmail.com.
authors.forename: Pengling
authors.initials: P
authors.lastname: Shi
authors.affiliation: Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China. Electronic address: hongshen@ihb.ac.cn.
authors.forename: Hong
authors.initials: H
authors.lastname: Shen
authors.affiliation: Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Wang
authors.affiliation: College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Wenjie
authors.initials: W
authors.lastname: Chen
authors.affiliation: Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China. Electronic address: xieping@ihb.ac.cn.
authors.forename: Ping
authors.initials: P
authors.lastname: Xie
mesh_terms: D002681:China; D017377:Diatoms / Q000254:growth & development / Q000378:metabolism* / Q000528:radiation effects*; D005068:Eutrophication; D007700:Kinetics; D008027:Light; D010758:Phosphorus / Q000378:metabolism*; D012825:Silicon / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D010758:Phosphorus; D012825:Silicon
keywords: Diatom; Light intensity; Michaelis–Menten equation; Phosphorus; Silicon; Uptake kinetics