南亚热带水体7种常见浮游动物的个体氮、磷含量及其排泄率的比较

摘要

We examined the excretion of phosphorus and nitrogen of seven common zooplankton species in South China,Brachionus calyciflorus,Asplawchna priodonta,Bosminopsis deitersi,Moina micrura,Daphnia similoides sinensis,Mesocyclops therrnocyclopoides and Phyllodiaptomus tunguidus under different temperature (15-30℃C).The nitrogen and phosphorus content of the seven species were also analyzed to test the hypothesis that variation in nutrient excretion rate is related to body P and N content.Body P and N content were 4.9-24.2 μg/mg dry weight (DW) and 51.2-153.5 μg/mg(DW) respectively,and their atom ratio was 11.5-43.0.Body P content was significantly related to body dry weight.However,both body N content and N ∶P ratio were not significantly related to body dry weight.The mass-specific excretion rate of dissolved inorganic phosphorus (DIP) was 0.31-2.05 μg/(mg(DW) · h),negatively related to body dry weight,and positively to temperature and body N ∶P ratio.The mass-specific excretion rate of total dissolved nitrogen (TDN) was 24-256 μg/(mg(DW) ·h),negatively related to body dry weight and positively to temperature.Atom ratio of TDN to DIP excretion was 112-352,positively related to temperature,and negatively to body dry weight and N ∶P ratio.Our results indicated that zooplankton fed on food with high N ∶P ratio tend to excrete nutrients with a high nitrogen excretion rate and high ratio of TDN ∶ DIP in South China,and interspecific difference of P excretion and TDN ∶ DIP ratio of the excretion would be ascribed partly to body dry weight and N ∶P ratio.%比较分析了我国南亚热带湖库7种常见浮游动物,萼花臂尾轮虫(Brachionus calyciflorus)、前节晶囊轮虫(Asplanchna priodonta)、颈沟基合潘(Bosminopsis deitersi)、微型裸腹涵(Moina micrura)、中华拟同型溞(Daphnia similoides sinensis、温中剑水蚤(Mesocyclops thermocyclopoides)和舌状叶镖水蚤(Phyllodiaptomus tunguidus)在温度15～ 30℃范围内的氮、磷排泄率以及氮、磷含量.氮、磷含量分别为4.9～24.2 μg/mg(DW)和51.2～ 153.5 μg/mg(DW);氮磷原子比为11.5～43.0.磷含量与个体干重呈显著正相关关系,但氮含量和氮磷比与个体干重相关性不显著.溶解态无机磷(DIP)排泄率为0.31～2.05 μg/(mg(DW)·h),与个体干重呈显著负相关,与温度和个体氮磷含量比值均呈显著正相关.总溶解态氮(TDN)排泄率为24～256 μg/(mg(DW)·h),与温度和个体干重均呈显著相关,但与个体氮磷含量比值相关性不显著.排泄的TDN:DIP原子比为112～352,与温度呈显著正相关,与个体干重和氮磷含量比值均呈显著负相关.结果表明,在高氮磷比的食物条件下,7种浮游动物营养盐排泄均呈现高的氮磷比特征,磷排泄率和排泄的氮磷比的种间差异受个体干重和个体氮磷比影响.