大亚湾沉积物中浮游植物休眠体萌发研究

为了解孢囊在浮游植物种群动态及赤潮发生中的作用,于2005年4月~2006年6月采集大亚湾养殖海域沉积物样品,经孔径为125,20μm的网筛过滤,在25℃下进行萌发,观察培养20,40d的浮游植物休眠体的萌发状况.结果表明,共萌发出浮游植物27属37种.裸甲藻(Gymnodinium corii Schiller)为优势甲藻类,其占甲藻细胞数量平均百分比为73.1%,最高百分比可达99.7%.定鞭藻中的金色藻(Chrysochromulima spp.)和蓝藻中的拟鱼腥藻(Anabaenopsis spp.)也萌发出较高数量.不同时间培养、萌发的浮游植物种类组成有所差异,同时也随沉积物捕捉时间的不同而出现一定的季节差异.休眠体的萌发可在一定程度上反映水体浮游植物组成,但在萌发中大量出现的一些微型和微微型浮游植物可能会由于体型过小而在浮游植物监测中被忽略.

Investigation on germination of phytoplankton resting cells in sediment traps collected from Daya Bay,South China Sea

In order to understand the effect of cyst beds on phytoplankton population dynamics and redtide occurrence, sediments were collected from two stations in the aquacultural areas of Daya Bay, South China Sea from April 2005 to June 2006. Sediments were filtered through 20 and 125 μm of seive, and incubated at 25℃ for 20 d and 40 d. A total of 37 phytoplankton species, belonging to 27 genera, were obtained from germination incubation. Gymnodinium corii Schiller, a first recorded species from the China Sea, was the dominant dinoflagellate species, average accounting for 73.1% of the proliferating dinoflagellate cells, but the highest proportion could reach 99.7%. Haptophyta species Chrysochromulima spp. and cyanobacteria species Anabaenopsis spp. also occurred abundantly. The composition of phytoplankton species was different after 20d and 40d incubation germination or in different collection seasons. The germination of resting cells mirrored the phytoplankton composition in the water column to some extent. However, some nannophytoplankton species such as Gymnodinium corii, Chrysochromulima spp. and cyanobacteria species Anabaenopsis spp., occurred abundantly in germinated phytoplankton, were seldom reported in water column in previous phytoplankton surveys, which might be ignored due to their small sizes.