Dinoflagellate cyst taphonomy based on a sediment trap experiment

1)甲藻孢囊通量的季节变化1998~2005年每两个月采集一次沉积物捕捉器样品，以了解日本大村湾甲藻孢囊通量的种类组成和季节变化。在秋季和冬季，活孢子囊的通量有明显的季节变化，且通量数较高。共记录了43个不同的孢囊分类群，它们由两个不同的生态类群组成。第一类包括扁茎原球藻和枯草原球藻，它们在每年秋季到冬季都会增加。第二类群包括Goniaulax spp.和Pheopolykrikos hartmannii，并全年被困。这两个组表现出不同的通量模式，在营养上分别是异养和自养。异养组以类包膜包囊为主。已知类原藻类的营养细胞主要以硅藻为食。样品硅藻通量也增加了秋到冬。Therefo…更重要的是，秋季至冬季类原生物孢囊的增加与硅藻水华有关。另一方面，自养类群中，一般全年都可以观察到以类钩虾卵为主的自养群，但出现的季节不同。也许它们能对有利的环境条件作出反应。异养甲藻Protperiddium thulesense有一种特殊的形态特征组合，即运动细胞的膜板排列类似于典型的原鞭毛虫，而包囊的形状和原型则类似于双叶藻。我们通过包囊培养和膜平板分析，结合基于SSU rDNA序列的分子系统发育研究，重新研究了苏云金杆菌的包囊-运动关系。采用单细胞聚合酶链式反应方法，对大村湾分离的5株苏云金杆菌、3株原藻和3株复藻进行了检测。从田间标本分离的活动细胞和从孢子中萌发的活动细胞的膜板排列是相同的。板式为：Po，X，3‘，3a，7“，3+TC，4s，5”’，2“。苏氏对虾的包囊为圆形和棕色，具复叶原基，与双壳类相似。较少

1)Seasonal Change of dinoflagellate cyst fluxSediment trap samples were harvested bimonthly from 1998 to 2005 and examined to better understand the species composition and seasonal variation of dinoflagellate cyst flux in Omura Bay in Japan. Samples living cyst flux clearly showed seasonal variation with the higher flux number between autumn and winter. In total, 43 different cyst taxa were recorded and these were composed of two different ecological groups. The first group included Protoperidinium compressum and P.subinerme, which increased every autumn to winter. The second group included Gonyaulax spp. and Pheopolykrikos hartmannii, and was trapped throughout the year. These two groups manifested the different flux patterns, and were respectively heterotrophic and autotrophic in nutrition. In the heterotrophic group, protoperidinioid cysts were dominant. Vegetative cells of protoperidinioid are known to feed mainly diatoms. Sample diatom flux also increased autumn to winter. Therefo … More re, the increase of protoperidinioid cysts in autumn to winter was observed to correlate with diatom blooms. On the other hand, autotrophic group mostly consisting of Gonyaulacoid cysts were observed throughout the year in general, however occurrence seasons of these cysts were different. Probably they can respond to favorable environmental conditions. This strongly suggested that the different behavior in cyst production is closely related to different nutrition.2)Cyst incubation experiment for establishing cyst-motile form relationshipThe heterotrophic armored dinoflagellate Protoperidinium thulesense has an unusual combination of morphological characters, i.e. the thecal plate arrangement of the motile cell resembles a typical Protoperidinium, whereas the shape and archeopyle of the cyst are like the diplopsalids. We have re-examined the cyst-motile relationship of P.thulesense by cyst incubation and thecal plate analysis together with a molecular phylogenetic study based on SSU rDNA sequences. Five isolates of P.thulesense, including motile cells and cysts from Omura Bay, and three Protoperidinium and three diplopsalid species were examined by using the single cell PCR method. The thecal plate arrangement of the motile cells isolated from field samples and those germinated from cysts were identical. The plate formula was ; Po, X, 3', 3a, 7", 3+tc, 4s, 5"', 2"". The cysts of P.thulesense were round and brown with a theropylic archeopyle, and rather similar to the diplopsalid species. Less