磷限制对莱州湾浮游植物碳氮磷化学计量特征影响的实验研究OA

The study was conducted in the Laizhou Bay,a region characterized by high nitrogen levels,low phosphorus levels,and severe phosphorus limitation.Through in-situ mesocosm experiments regu-lated by nitrogen-to-phosphorus ratios and laboratory cultivation experiments of different phytoplankton types,the stoichiometric characteristics of phytoplankton under varying N/P conditions were analyzed.The results indicate that phytoplankton in Laizhou Bay exhibit flexible absorption of nitrogen and phos-phorus nutrients.Under non-phosphorus-limited conditions,phytoplankton absorb nutrients essentially according to the Redfield ratio(16∶1),and the intracellular ratios of particulate organic carbon(POC)to particulate nitrogen(PN)to particulate phosphorus(PP)closely approximate the Redfield ratio(106∶16∶1).Under phosphorus-limited conditions,phytoplankton luxuriously absorb and assimilate nitrogen,leading to intracellular POC/PN ratios lower than the Redfield ratio,while POC/PP and PN/PP ratios become higher than the Redfield ratio.Furthermore,as the N/P ratio increases,the POC/PN ratio decreases,whereas the POC/PP and PN/PP ratios increase.Phosphorus limitation causes an im-balance in the intracellular POC/PN/PP ratios of phytoplankton,resulting in an increase in high-carbon substances within the cells and a reduction in carbon assimilation efficiency.