title: [Growth of Platymonas helgolandica var. tsingtaoensis, Cylindrotheca closterium and Karenia mikimotoi and their survival strategies under different N/P ratios].
abstract: In this study, laboratory culture experiments were carried out in a batch culture system, with the focus on the effect of different N/P ratios (1:1, 4:1, 16:1, 80:1 and 160:1) on the growth of Platymonas helgolandica var. tsingtaoensis, Cylindrotheca closterium and Karenia mikimotoi. The cell abundance, growth rate, and chlorophyll a and protein contents were measured every 24 h for one week. The results showed that N/P ratio significantly affected the growth of three kinds of algae. Cylindrotheca closterium grew fastest under 160:1 N/P ratio, while Platymonas helgolandica var. tsingtaoensis and Karenia mikimotoi grew fastest under 4:1 and 80:1 N/P ratio, respectively. The maximum cell density of the phytoplankton was mainly influenced by cell size and specific growth rate, the synthesis of chlorophyll a was mainly affected by nitrogen, and high N/P ratio benefited the increase of chlorophyll a content. The protein concentration in cells correlated significantly with N/P ratio, cell size and cell period. As for survival strategy, Cylindrotheca closterium showed obvious features of fast-reproductioned r-selective species, whereas Platymonas helgolandica var. tsingtaoensis and Karenia mikimotoi were most likely to be the more competitive K-selected species.
authors.affiliation: Key Laboratory of Marine Ecology and Environmental Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China. sunjun@ms.qdio.ac.cn
authors.forename: Jun
authors.initials: J
authors.lastname: Sun
authors.forename: Dongyan
authors.initials: D
authors.lastname: Liu
authors.forename: Zongtao
authors.initials: Z
authors.lastname: Chan
authors.forename: Tiandi
authors.initials: T
authors.lastname: Wei
mesh_terms: D000222:Adaptation, Physiological; D002734:Chlorophyll / Q000096:biosynthesis; D009584:Nitrogen / Q000494:pharmacology*; D010758:Phosphorus / Q000494:pharmacology*; D010839:Phytoplankton / Q000254:growth & development* / Q000378:metabolism; D013045:Species Specificity
chemical_list: D002734:Chlorophyll; D010758:Phosphorus; D009584:Nitrogen