网采海洋浮游植物中生源硅的提取与测定

Extraction and Determination of Biogenic Silica in Marine Phytoplankton Samples Collected with Plankton Net

浮游植物生产是海洋生物地球化学循环的重要环节,其产物之一的生源硅是海洋沉积物中的主要生源成分。为了解浮游植物中生源硅的含量、分布、变化以及对沉积物生源组分的贡献,在近岸海域用浮游生物网采集了浮游植物样品,选用碳酸钠为提取剂,对提取和测定的条件进行了实验,确定了近岸海域网采海洋浮游植物试样中生源硅测定的化学提取方法。该方法的适宜提取条件为:碳酸钠浓度为2 mol/L,固液比以5 mg/mL为佳,在85℃恒温水浴间歇震荡1.5 h提取生源硅,以硅钼蓝法测定,所得结果有很高的重现性。方法的检出限为0.005%,精密度可达0.03%~0.36%。

Biological production of phytoplankton is an important process for the marine biogeochemical cycle.One of its products,the biogenic silica,is a major biogenic component of marine sediment,which is an important parameter for geochemical studies.In order to study the content,spatial distribution and temporal variation of biogenic silica in phytoplankton,a chemical extraction method with sodium carbonate was chosen for the determination of biogenic silica with phytoplankton samples from coastal area.The extraction conditions,including concentration of sodium carbonate,extraction time and solidliquid ratio were tested and confirmed.The optimal conditions with high reproducibility for the extraction and determination of biogenic silica of phytoplankton samples from coastal seas are: the concentration of sodium carbonate is 2 mol/L,the solid-liquid ratio is 5 mg/mL,and the extraction time is 1.5 h in a water bath at a constant temperature of 85 ℃.The detection limit of this method is 0.005% with high precisions between 0.08% to 0.36% relative to the initial amounts of phytoplankton samples.