流溪河水库颗粒有机物及浮游动物碳、氮稳定同位素特征  

Carbon and nitrogen stable isotope characteristics of particulate organic matter and zooplankton in Liuxihe Reservoir

作　　者：宁加佳[1] 刘辉[1] 古滨河[1,2] 刘正文[1,3] 

机构地区：[1]暨南大学水生生物研究所,广州510632 [2]美国佛罗里达大学水和土壤科学系,佛罗里达32611 [3]中国科学院南京地理与湖泊研究所,南京210008

出　　处：《生态学报》2012年第5期1502-1509,共8页Acta Ecologica Sinica

基　　金：NSFC-广东联合基金资助项目(U0733007)

摘　　要：为了解影响流溪河水库颗粒有机物(POM)碳和氮稳定同位素(δ13C和δ15N)变化的主要因素,及其与浮游动物δ13C和δ15N之间的关系,于2008年5月至12月份对POM及浮游动物的δ13 C和δ15 N进行了研究。颗粒有机物碳稳定同位素(δ13CPOM)和氮稳定同位素(δ15NPOM)的季节性变化幅度分别为5.1‰和2.2‰,5月和7月份δ13CPOM较高,而在10月和12月份降低,这主要与降雨将大量外源有机物带入水库而引起的外源及内源有机物在POM组成上发生变化有关。δ15NPOM总体呈上升趋势,可能是由降雨引起的外源负荷、初级生产力、生物固氮等因素共同作用的结果。浮游动物的δ13C及δ15N总的变化趋势与POM的相似,也具有明显的季节性变化,食物来源的季节变化可能是造成其变化的主要原因。在5月份,浮游动物的食物来源为POM中δ13C较高的部分,也就是外源有机物,而在10月及12月份,其食物则可能主要为浮游植物。Particulate organic matter （POM） in lakes originates from autochthonous （macrophytes and phytoplankton） and allochthonous （terrestrial detritus） inputs into the surface water of lakes. There are many factors that can influence the composition of POM, such as rainfall, temperature, solar radiation, water velocity, hydrological retention time. Because the carbon （δ13C） and nitrogen （δ15N） stable isotope ratios of the terrestrial detritus fraction in POM is often different from algal fraction, the isotopic compositions of POM reflect the relative proportions of terrestrial and aquatic contributions. In addition, many factors in lakes influence the values of δ13CPOM and δ15NPOM： these include primary productivity, trophic state, external loading, and isotopic composition of dissolved inorganic carbon and nitrogen. Zooplankton can graze on a wide range of food sources （i.e. phytoplankton, detritus, and bacteria）. As a result, phytoplankton- and terrestrial- derived C may be conveyed to zooplankton and hence to higher trophic levels, along several direct and indirect pathways. Because the isotope ratios of consumers reflect those of their diet, the δ13C and δ15N of zooplankton will be affected when isotopic composition of POM changes over time. In order to understand the factors influencing the seasonal variations in carbon and nitrogen stable isotopes of POM and zooplankton and to assess relationship between POM and zooplankton, especially the relative importance of autochthonous and allochthonous materials to zooplankton, δ13C and δ15N of POM and zooplankton were analyzed in Liuxihe Reservoir from May to December in 2008. As the results of relatively stable solar energy inputs and low trophic state, the seasonal amplitudes of δ13CPOM and δ15NPOM in Liuxihe Reservoir were small, displaying seasonal variations of 5.1‰ and 2.2‰ due to the monsoon climate and summer storms. δ13CPOM was high in May and July and then decreased dramatically. Precipitation had significant positive cor

关 键 词：颗粒有机物 降雨 浮游动物 δ13C δ15N 

分 类 号：Q958.8[生物学—动物学]