Effects of ambient DIN:DIP ratio on the nitrogen uptake of harmful dinoflagellate Prorocentrum minimum and Prorocentrum donghaiense in turbidistat

作     者：李纪 Patricia M. GLIBERT Jeffrey A. ALEXANDER 

作者机构：University of Maryland Center for Environmental Science Horn Point Laboratory PO Box 775 Cambridge MD 21613 USA 

出 版 物：《Chinese Journal of Oceanology and Limnology》 (中国海洋湖沼学报（英文版）)

年 卷 期：2011年第29卷第4期

页      面：746-761页

核心收录：

学科分类：083002[工学-环境工程] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 07[理学] 08[工学] 09[农学] 0903[农学-农业资源与环境] 0713[理学-生态学] 

基　　金：supported by the University of Maryland Center for Environmental Science (UMCES)  Horn Point Laboratory. This is UMCES contribution number 4503 

主　　题：harmful dinoflagellate N:P ratio nitrogen uptake continuous culture Prorocentrum spp 

摘      要：The effects of varying nitrogen （N）： phosphorus （P） ratios on the growth and N-uptake and assimilation of the harmful dinoflagellates Prorocentrum minimum and Prorocentrum donghaiense were examined in turbidistat culture experiments. Algal cultures were supplied with media containing PO4^3- in various concentrations to obtain a wide range of N：P ratios. Experiments to determine rates of N uptake and assimilation of different N sources （NO^3-, NH4^＋, urea and glycine by P. minimum and NO3^-, NH4^＋ by P. donghaiense） were conducted using ^15-N tracer techniques at each N：P ratio. The growth rates suggested nutrient limitation at both high and low N：P ratios relative to the Redfield ratio. On a diel basis, the growth of both species was regulated by the light-dark cycle, which may be a result of regulation of both lightdependent growth and light-independent nutrient uptake. Maximum growth rates of both species always occurred at the beginning of light phase. In P-rich medium （low N：P ratio）, both species had higher N assimilation rates, suggesting N limitation. Low assimilation coefficients at high N：P ratios suggested P limitation of N uptake and assimilation. NO3 ^-and NH4^＋ contributed more than 90% of the total N uptake of P. minimum. Reduced N sources were more quickly assimilated than NO3^-. Highest average daily growth rates were recorded near an N：P ratio of 12 for both species. The N uptake rates of cultures at N：P ratios near Redfield ratio were more balanced with growth rates. The linkage between growth rates and N uptake/assimilation rates were conceptually described by the variation of cell N quota. The N：P ratios affect the N uptake and growth of Prorocentrum spp., and may regulate their bloom progression in eutrophic ecosystems.