|导师||肖天 ; 张武昌|
|关键词||砂壳纤毛虫 生物地理分布类型 群落特点 交汇|
在东海至楚科奇海的大空间尺度断面上，砂壳纤毛虫北方型、广布型、近岸型和暖水型种类都有出现。根据北方型和暖水型种类的出现情况，整个断面被划分成砂壳纤毛虫东海浅水群落、日本海暖水群落和北方群落。北方群落的范围包括宗谷海峡以北到楚科奇海的所有区域，丰度高值出现在阿拉斯加洋流两个分支与亲潮的交汇处并呈向南向北降低的趋势，北极海域的大部分站位丰度低于10 ind. L-1。棘口虫属 (Acanthostomella)、类铃虫属 (Codonellopsis)、拟网纹虫属 (Parafavella)和笛杯虫属 (Ptychocylis)为北方群落中的优势属，贡献了北方群落中各站位丰度的79.07±29.67% (n=49)，这四属优势属的丰度分布呈显著的正相关关系。22-26 μm 和38–42 μm口径组的砂壳纤毛虫分别贡献了北方群落总丰度的67.35%和15.13%。砂壳纤毛虫的分布特征显示宗谷海峡是砂壳纤毛虫扩散的天然障碍。
我国近海至热带西太平洋海区三个断面砂壳纤毛虫多属于广布型、近岸型和暖水型三种分布类型。L和M断面的近岸站位，近岸型种类在种类数和丰度上占优势；大洋站位，暖水型和广布型种类在种类数和丰度上均占绝对优势。根据有无暖水型种类出现可以划分出近岸群落和暖水群落。W断面全部为暖水群落，砂壳纤毛虫种丰富度 (12-40种)和多样性指数 (2.03-4.76)都很高。L和M 断面种丰富度和多样性指数在近岸群落站位较低，种丰富度均在10种以下，多样性指数多在2以下；暖水群落各站位种丰富度均大于10，多样性指数多在2.5以上。三个断面最南部的几个站位种丰富度和多样性指数均稍有降低。三个断面的暖水群落均是22-26 μm口径组的种类对总丰度的贡献率最高，W、L和M断面分别为27.82%、30.76%和38.56%。砂壳纤毛虫暖水群落的特点是种丰富度高、丰度低、多样性指数和均匀度指数均很高。
珠江口砂壳纤毛虫在丰水期种丰富度较高，而且丰水期透明壳种类相对较多。砂壳纤毛虫的分布与盐度密切相关，根据各种分布的盐度范围可以把砂壳纤毛虫划分成三种类型：低盐种、中盐种和高盐种。梅氏拟铃虫 (Tintinnopsis mayeri)是唯一的低盐种，但在丰水期可以扩散到盐度较高的区域。厦门拟铃虫 (T. amoyensis)、穗缘拟铃虫 (T. fimbriata)、矮小拟铃虫 (T. nana)、触角拟铃虫 (T. tentaculata)、管状拟铃虫 (T. tubulosa)和诺氏薄铃虫 (Leprotintinnus nordqvisti)属于中盐种，在两个航次都有出现，并主要出现在盐度适中的站位；高盐种的分布有明显的季节变化：尖底类瓮虫 (Amphorellopsis acuta)、横口拟铃虫 (T. plagiostoma)和筒状拟铃虫 (T. tubulosoides)在两个航次均有出现；而斯氏拟铃虫 (T. schott)、妥肯丁拟铃虫 (T. tocantinensis)和双厚领铃虫 (Wangiella dicollaria)只在丰水期出现。丰水期和枯水期都可以划分出低盐群落、中盐群落和近岸群落三种砂壳纤毛虫群落；丰水期还有一个明显的混合群落。在不同的群落中砂壳纤毛虫的优势口径组不同。
|其他摘要||In this dissertation, surface tintinnids distribution of the East China Sea, a transect from the East China Sea to the Chukchi Sea, transects from coastal waters of China to the tropical western Pacific, and the Pearl River Estuary were studied. The purposes of this study were to find out the factors influencing the expansion of different tintinnids biogeographical types, the characteristics of different tintinnids communities, and the adaptation abilities of different tintinnids to the environment variation. |
In the East China Sea, most tintinnid genera belonging to neritic, warm water and cosmopolitan biogeographical types. According to the difference in their expansion ability, neritic and warm water types could be divided into core genera and pioneer genera. In the case of neritic type, core and pioneer neritic genera stayed together in spring and summer while pioneer neritic genera expanded a lot out to the oceanic water in autumn. In the case of warm water type, the pioneer genera always expanded a lot out to the coast in all three seasons. In spring and summer, the pioneer genera of neritic and warm water types did not meet. However, in autumn, the core genera of neritic and warm water types collided. The factor influencing the distribution of neritic type was water depth while salinity was the factor influencing the distribution of warm water type.
Boreal, cosmopolitan, neritic and warm water biogeographical types occurred along the transect from the East China Sea to the Chukchi Sea. According to the presence of boreal and warm water types, three tintinnid communities (the East China Sea neritic community, the Japan Sea warm water community, and the boreal community) were identified along the transect. The boreal community extended from the Chukchi Sea to the waters north of the Sōya Strait. Abundance peaks occurred at stations in the crossroads of two branches of the Alaska Current and Oyashio Current, and decreased both northward and southward. The abundance was <10 ind. L-1 at most stations in Arctic region. The dominant genera (Acanthostomella, Codonellopsis, Parafavella, and Ptychocylis) accounted for 79.07±29.67% (n=49) of the abundance in the boreal community. The abundance of the four dominant genera covaried with strongly significant positive correlations. Tintinnids in 22–26 μm and 38–42 μm LOD size-classes were dominant and contributed 67.35% and 15.13%, respectively, to the total abundance in the boreal community. The distribution and abundance of tintinnids in the study area suggest that the Sōya Strait might be a geographical barrier for tintinnids expansion.
Most tintinnids belong to cosmopolitan, neritic and warm water biogeographical types along the three transects from coastal waters of China to the tropical western Pacific. Neritic tintinnids were dominant both in number of species and abundance at coastal stations in transects L and M. At oceanic stations, cosmopolitan and warm water tintinnids were dominant at both number of species and abundance. Neritic community and warm water community were divided according to whether warm water tintinnids occurred. Tintinnid community in transect W was a warm water community, both species richness (12-40 species) and diversity index (2.03-4.76) were high. Species richness and diversity index were low in neritic communities in transects L and M. Species richness was < 10 species at each station, diversity index was < 2 at most stations in neritic communities. Species richness was > 10 species at each station, diversity index was > 2.5 at most stations in warm water communities in transects L and M. Both species richness and diversity index had a slight decrease at the southmost stations in the three transects. Species in 22-26 μm LOD size-class was the highest contributor in warm water communities, accounted for 27.82%, 30.76% and 38.56% of the total abundance in transects W, L and M, respectively. The characteristics of warm water communites in the three transects were high species richness, low abundance, high diversity index and evenness index.
In the Pearl River estuary (South China Sea), tintinnid species richness was higher and more hyaline tintinnid species were identified in rainy than in dry season. The tintinnid species distribution was greatly linked to salinity, leading to their assignment to 3 types (oligohaline, mesohaline and polyhaline species) according to the salinity associated to their occurrence. Tintinnopsis mayeri was an oligohaline species and could expanded to much higher salinity region in rainy season. The mesohaline species, which were mainly found in middle salinity, were T. amoyensis, T. fimbriata, T. nana, T. tentaculata, T. tubulosa, Tintinnopsis sp. and Leprotintinnus nordqvisti. They present in both cruises. The distribution change of polyhaline species was obvious in rainy and dry seasons: Amphorellopsis acuta, T. plagiostoma and T. tubulosoides occurred at both cruises, but T. schott, T. tocantinensis and Wangiella dicollaria disappeared in rainy season. Three communities (low salinity; brackish water and coastal communities) could be identified at both cruises. One additional community (mixed community) was distinguished in the rainy season only. The dominant LOD size-classes varied within communities.
From comparing the tintinnid data in different regions in this dissertation, it can be seen that species richness increased with the decrease of latitude, and had a slight decrease at the southmost stations. Species richness increased along with the salinity increase in the Pearl River estuary. Tintinnid abundance was low at tropical and Arctic oceans, but was high at temperate oceans. Tintinnid diversity index increased with the decrease of latitude, and it was much lower in the estuary area than that in the oceanic area with the same latitude. Tintinnids in 22–26 μm LOD size-classe was dominant in both boreal and warm water communities.
|李海波. 不同水团中砂壳纤毛虫群落及交汇[D]. 北京. 中国科学院大学,2016.|