不同处理方法对沉积物中甲藻孢囊计数与萌发的影响

Effects of different separation and concentration methods on counting and germination of cysts of Scrippsiella trochoidea

甲藻孢囊是海洋沉积物中最重要的化石成分之一,而沉积物处理是孢囊定性定量研究的基础。本文以锥状斯氏藻(Scrippsiella trochoidea)孢囊为实验材料,研究了筛网过滤处理和多钨酸钠密度梯度离心对孢囊计数和萌发实验的影响。纯孢囊经过筛网过滤后的回收率为74.5%,而孢囊与沉积物的混合液筛网过滤后的回收率下降至61.9%。1.5 g/cm3的多钨酸钠对纯孢囊进行密度梯度离心,回收率为68.6%;而沉积物中的孢囊经过筛网过滤和多钨酸钠密度梯度离心后,回收率下降至42.6%。筛网过滤法处理沉积物样品不影响孢囊萌发,而多钨酸钠离心后萌发率显著降低。同时,多钨酸钠处理可使锥状斯氏藻孢囊形态发生改变。本研究结果表明筛网过滤法仍然是沉积物中孢囊收集和处理的可靠方法。

Dinoflagellate cyst is one of the most important fossil components in marine sediments. A range of laboratory preparation methods have been developed to deal with the extraction of dinoflagellate cysts in sediments. Here,we present a comparison of sieving and sodium polytungstate（SPT） density-gradient centrifugation on counting and germination of cysts of Scrippsiella trochoidea. The recovery rate of pure cysts was 74. 5% after sieving through 125 μm and 20 μm screens successively. The recovery rate decreased to 61. 9% for cysts in sediments after sieve procedures.The recovery rate was 68. 6% for pure cysts after 1. 5 g/cm3 SPT gradient centrifugation,and decreased to 42. 6% for cysts in sediments after sieving and SPT gradient centrifugation successively. Sieving did not influence cyst germination,however the germination rates decreased significantly after SPT centrifugation. Meanwhile,SPT treatment made morphological changes of cysts of S. trochoidea. The results suggest that sieving is a reliable method for separation and concentration of cysts from sediments.