中文摘要：

利用采水的方法，从东、黄海海域代表性站位采集若干样品，在完成现场固定、静置沉淀浓缩、浓硫酸酸化、煮沸以及蒸馏水水洗等一系列样品处理步骤之后．分别置于透射电镜（TEM）和扫描电镜（SEM）下对样品中微型硅藻进行分类学研究，观察到2个我国新记录的种类。它们是拟弱小异极藻Gomphonema pseudexiguum Simonsen和簇生针杆藻Synedra fasciculate（C．Agardh）Kutzing．拟弱小异极藻的主要特征是具有明显的蝴蝶结状中央区．尾端壳缝具“T”形结构．簇生针杆藻的主要特征是拟壳缝显著．壳面末端有一明显的唇形突．对新纪录种及其近似种类进行了形态学比较研究．

英文摘要：

Seawater samples （each 2 L） were collected at several representative spots in the East China Sea and Huanghai Sea in November 2000 and April 2001 respectively. They were [ixed using Lugol＇s solution in situ,concentrated to a final volume of about 5mL by settlement overnight, cleaned with concentrated H2SO4 by being boiled for 20- 30 minutes in water bath and rinsed with distilled water to neutrality in the laboratory. The nanoplanktonic diatom species were studied using transmission electron microscope （TEM） and scanning electron microscope （SEM） respectively. And two species were identified as new records for China. They were Gornphonerna pseudexiguum Simonsen and Synedra fasciculate （C. Agardh） Kutzing. G. pseudexiguum is characterized by a central area like bowknot or crisscross and ＂T＂ frame at the foot pole. The main features of S. fasciculate are the presence of distinct pseudoraphe and a single rimoportula situating at each pole. Several resembling species were discussed in point of morphological traits.