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 

机构地区：[1]University of Maryland Center for Environmental Science, Horn Point Laboratory, PO Box 775, Cambridge MD 21613, USA

出　　处：《Chinese Journal of Oceanology and Limnology》2011年第4期746-761,共16页中国海洋湖沼学报（英文版）

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

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.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 PO34? 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 (NO3?, NH4+, urea and glycine by P. minimum and NO3?, NH4+ by P. donghaiense) were conducted using 15N 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 light- dependent 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.

关 键 词：harmful dinoflagellate N：P ratio nitrogen uptake continuous culture Prorocentrum spp 

分 类 号：X55[环境科学与工程—环境工程] X173