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PRESERVATION OF DINOFLAGELLATE CYSTS IN SURFACE SEDIMENTS OF INNER BAYS

内湾表层沉积物中甲藻包囊的保存

基本信息

批准号：
10640452
负责人：
MATSUOKA Kazumi
金额：
$ 2.11万
依托单位：
Nagasaki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

For clarifying a change such as nutrients in aquatic environments, such phytoplankton communities as diatoms and dinoflagellates are very useful. In dinoflagellates the vegetative cell community is more useful than the cyst community, especially the eutrophication. Unfortunately all modern dinoflagellates can not produce a resting cyst which is preserved in sediments. Therefore, when we employ the cyst community, we have to understand a bias of dinoflagellate cyst preserved in sediments. Unfortunately there are only a few study on this subject for the moment.In this study, we collected plankton and cyst samples from Matoya Bay in Mie the 0mura Bay in Nagasaki Prefecture, where historical record of dinoflagellate vegetative cells has been kept throughout over past 30 years. In 2 sites of Matoya Bay and 1 site 0mura Bay, three core sediments were collected with a handy piston core with out serious disturbance of sediments. After measurement of 210Pb, the average sedimentation rates of these cores are estimated as 0.55cm/year (Matoya Bay St.1), 0.41cm/year (Matoya Bay St. 2) and 0.31cm/year (0mura Bay St.5). According to these sedimentation rates, the record in sediments may be back to 120, 125 and 145 years ago respectively.Dinoflagellate cyst community of St.1 in Matoya Bay consists of at least 18 genera and 34 species including several undeterminable species. In gonyaulacoid group, Lingulodinium machaerophorum (= L. polyedrum), Spiniferites bulloideus (= Gonyaulax scrippsae), Spiniferites belerius were dominated and Brigantedinium spp. (= Protoperidinium spp.) were abundant in protoperidinioid group. 32 genera and 134 species of plankton form were identified. Among them, only 9 genera and 17 species in cyst forms were corresponding with plankton species. In particular, no cysts of prorocentlales and dinophysales were recovered from the sediments. This strongly suggests that the information from cyst community is very limited in comparison with plankton community.

对于阐明诸如水环境中的营养物的变化，诸如硅藻和甲藻的浮游植物群落是非常有用的。甲藻营养细胞群落比孢囊群落更有利用价值，尤其是对富营养化的作用更大。不幸的是，所有现代甲藻都不能产生一个保存在沉积物中的休眠包囊。因此，当我们使用孢囊群落时，我们必须了解甲藻孢囊在沉积物中保存的偏好。本研究以保存了30多年甲藻营养细胞历史记录的长崎县三重村湾的松屋湾为研究对象，采集了浮游生物和囊藻样品。在Matoya湾的2个站位和0 mura湾的1个站位，用一个轻便的活塞岩芯采集了3个沉积物，没有严重的沉积物扰动。经~（210）Pb测定，这些柱状样的平均沉积速率分别为0.55cm/年（Matoya Bay St.1）、0.41cm/年（Matoya Bay St.2）和0.31cm/年（0 mura Bay St.5）。根据这些沉积速率，沉积物中的记录可分别追溯到120、125和145年前。Matoya湾St.1的甲藻孢囊群落至少包括18属34种，其中包括一些未定种。在角裂藻群中，Lingulodiniummachaerophorum（= L. polyedrum）、Spiniferites bulloideus（= Gonyaulax scrippsae）、Spiniferites belerius和Brigantedinium spp.原多甲藻属在原多甲藻群中含量丰富。共鉴定出浮游生物32属134种。其中，囊胞型仅9属17种与浮游生物种相对应。特别是，从沉积物中没有发现原中齿藻目和甲藻目的孢囊。与浮游生物群落相比，囊藻群落所提供的信息是非常有限的。