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南大洋不同海区浮游纤毛虫群落研究
梁晨
Subtype博士
Thesis Advisor张武昌
2019-05-08
Degree Grantor中国科学院大学
Place of Conferral中国科学院海洋研究所
Degree Name理学博士
Keyword浮游纤毛虫群落 砂壳纤毛虫 丰度 水团 分布模式
Abstract

海洋浮游纤毛虫是海洋生态系统中重要的微型浮游动物。本论文通过对南大洋普里兹湾邻近海域、阿蒙森海以及南极半岛附近海域的浮游纤毛虫,特别是砂壳纤毛虫的空间分布进行调查,对比了不同海域浮游纤毛虫的分布模式,探究了普里兹湾邻近海域不同水团,包括夏季表层水(Summer Surface Water),冬季水(Winter Water)和绕极深层水(Circumpolar Deep Water)中浮游纤毛虫的空间分布,分析了阿蒙森海不同区域,包括南极区(Antarctic Zone)、极地锋(Polar Front)和亚南极区(Subantarctic Zone)中砂壳纤毛虫类群的分布情况,讨论了南极半岛附近海域浮游纤毛虫空间分布及与环境因子之间联系,最终描绘了浮游纤毛虫在南大洋地理分布的大致格局。

以往,浮游纤毛虫只有在南大洋不同生境中的研究,并没有考虑到水团的因素。在本研究中,我们报道了普里兹湾邻近海域纤毛虫类群在不同水团中的分布特点。根据海水的温度和盐度,该区域划分出了三个水团:夏季表层水(包括叶绿素a活体荧光值小于3和大于3的两部分)、冬季水和绕极深层水。浮游纤毛虫的丰度和生物量从夏季表层水(大于649 ± 559 ind./L,大于4.96 ± 4.98 μg C/L)、冬季水(228 ± 222 ind./L1.44 ± 1.35 μg C/L)到绕极深层水(94 ± 90 ind./L0.29 ± 0.33 μg C/L)依次降低。相对于其他水团,夏季表层水中叶绿素a活体荧光值大于3的部分砂壳纤毛虫丰度占总纤毛虫丰度比例最高(38.2%),无壳纤毛虫粒级最大(大于20 μm的个体占总纤毛虫的丰度超过了85%)。冬季水中南极本地种的砂壳纤毛虫占比最高(大于30%),其他水团占比不足15%。每个水团中都有其优势的砂壳纤毛虫类群:夏季表层水中,代表种类为未定种号角虫(Salpingella sp.)和高斯类铃虫(Codonellopsis gaussi);冬季水中,代表种类为有肋号角虫(Salpingella costata)、福雷号角虫(S. faurei)及德里波缘杯虫(Cy. convallaria forma drygalskii);船生孔环虫(Laackmanniella naviculaefera)和水晶波缘杯虫(Cy. convallaria forma cristallina)在夏季表层水中叶绿素a活体荧光值大于3的部分和冬季水中丰度都较高。绕极深层水中基本没有砂壳纤毛虫分布,但绕极深层水的涌升导致了纤毛虫丰度和生物量在表层出现了低值区,分布不连续。本研究探讨了浮游纤毛虫群落分布与水团之间的关系,即不同的水团中有其特定的优势砂壳纤毛虫种类,这些种类分布的时空变化与水团间的关系还需要进一步探究。

阿蒙森海砂壳纤毛虫的研究大部分是在一个相对狭窄的区域内,并且缺少砂壳纤毛虫的组成和分布信息。本研究共发现砂壳纤毛虫717种,包括一个未定种。其中9种属于南极本地种,主要分布在靠近南极大陆的南极区,占砂壳纤毛虫总丰度的比例超过60%。根据砂壳纤毛虫的丰度分布情况将它们分为四个组群:组群一(亚南极类群),包括挪威棘口虫(Acanthostomella norvegica)、冰生类铃虫(Codonellopsis glacialis)、微渺类铃虫(Cd. pusilla)和南极波缘杯虫(Cymatocylis antarctica),主要在极地锋的北边界分布;组群二(极地锋类群),包括杯状波缘杯虫(Cymatocylis convallaria forma calyciformis)、未定种(Unidentified species)和五边类瓮虫(Amphorellopsis quinquealata),主要在极地锋区分布;组群三(南极类群),包括有肋号角虫(S. costata)、梵氏波缘杯虫(Cymatocylis vanhoeffeni)、水晶波缘杯虫、德里波缘杯虫、漂流波缘杯虫(Cy. convallaria)、高斯类铃虫和船生孔环虫,主要南极区分布;组群四(广布类群),未定种号角虫在所有区域都有分布。我们发现了主要在极地锋区分布的砂壳纤毛虫类群——组群二,同时发现大口径(> 88 μm)的砂壳纤毛虫主要分布在南极区。本研究探讨了砂壳纤毛虫类群从南极区到极地锋的分布以及不同类群在极地锋区的交汇混合情况。我们的结果可以作为南极近岸到南极绕极流区砂壳纤毛虫类群分布研究的经典案例,为研究南大洋浮游生物大尺度分布情况提供思路和方向。

南极半岛附近海域浮游纤毛虫的研究主要集中在二十世纪八九十年代,大多数在海冰边缘区,而关于浮游纤毛虫从布兰斯菲尔德海峡到南奥克尼群岛这一片海域分布的研究基本没有。本研究中南极半岛附近海域浮游纤毛虫的平均丰度和生物量分别为636 ± 936 ind./L2.57 ± 3.56 μg C/L。纤毛虫丰度和生物量的高值区主要在50 m以浅,而在2断面出现了较明显的下沉。砂壳纤毛虫的平均丰度生物量分别为18 ind./L0.29 μg C/L,不同断面上砂壳纤毛虫的分布模式差异很大,砂壳纤毛虫在1断面主要在南侧从表层到底层分布,在2断面上由北到南逐渐从表层下沉到底层分布,而在3断面上刚好与2相反,56断面上砂壳纤毛虫主要在表层分布。无壳纤毛虫在纤毛虫群落中占主导地位,直接决定了浮游纤毛虫的分布模式。本次调查共检出砂壳纤毛虫616种,包括6种南极本地种。在本论文南大洋的调查中首次发现了近岸型砂壳纤毛虫未定种拟铃虫(Tintinnopsis sp.)。在该调查海区主要是南极本地种居多,并且倾向于分布在温度较低的水层中,其中水晶波缘杯虫和漂流波缘杯虫占优势,丰度平均值分别为4.20 ind./L4.15 ind./L,最大值分别为74 ind./L63 ind./L。主成分分析中第一主成分与温度最相关,表明南极本地种砂壳纤毛虫受温度影响较大,特别是水晶波缘杯虫和德里波缘杯虫。总氮、硝酸盐和硅酸盐对巴氏类铃虫(Cd. balechi)、漂流波缘杯虫和船生孔环虫分布的影响较大,呈显著负相关。本研究调查了南极半岛从布兰斯菲尔德海峡到威德尔海和斯科舍海交汇区,再到南奥克尼群岛之间的海域,涵盖了海峡、近岸、交汇区等多生境,系统研究了纤毛虫在复杂环境下的分布情况以及与环境因子之间的相关关系,为以后进一步的研究提供了基础。

本论文通过对南大洋三个海区浮游纤毛虫群落的研究,初步揭示了浮游纤毛虫在南大洋不同水团中的分布特点,砂壳纤毛虫类群在南极区、极地锋和亚南极区的分布模式,以及浮游纤毛虫在复杂环境下的分布情况,形成了南大洋浮游纤毛虫的大致分布格局,为进一步的研究提供了坚实的基础。

Other Abstract

The present study investigated the spatial distribution of planktonic ciliates in Prydz Bay, Amundsen Sea and seas near Antarctic Peninsula in the Southern Ocean. We compared ciliate distribution patterns in different areas in Antarctic waters. Our results revealed ciliate distributions in different water masses (Summer Surface Water, Winter Water and Circumpolar Deep Water), and tintinnid communities in Antarctic Zone, Polar Front and Subantarctic Zone. Meanwhile, we discussed the relationships between the tintinnids and the environment factors. Generally, our study roughly depicted a planktonic ciliates distribution structure in the Southern Ocean.

Planktonic ciliates are important microzooplanktons in pelagic ecosystems. The previous studies in Antarctic waters have only investigated the ciliate assemblages in different habitats without considering the water masses. Here, we reported the characteristics of ciliate assemblages in different water masses in open waters near Prydz Bay (East Antarctica) during austral summer. Three water masses were identified according to temperature and salinity: Summer Surface Water (SSW), Winter Water (WW) and Circumpolar Deep Water (CDW). Summer Surface Water was further divided into SSWChl a>3 (in vivo chlorophyll a>3) and SSWChl a<3 (in vivo chlorophyll a<3). Ciliate abundance and biomass in water masses decreased in the order SSW (>649 ± 559 ind./L, >4.96 ± 4.98 μg C/L) >WW (228 ± 222 ind./L, 1.44 ± 1.35 μg C/L) >CDW (94 ± 90 ind./L, 0.29 ± 0.33 μg C/L). Summer Surface Water Chl a>3 had a higher proportion (38.2%) of tintinnids to the total ciliate abundance and larger aloricate ciliates (ciliates in the 10-20 µm size class were <15% of the total aloricate ciliate abundance) than in other water masses. Winter Water had a higher proportion (>30%) of Southern Ocean endemic tintinnid species in total tintinnid abundance than in other water masses. Each water mass had the following indigenous tintinnid species: SSW, Salpingella sp., Codonellopsis gaussi; WW, Salpingella costata, S. faurei, Cymatocylis convallaria forma drygalskii and Cy. vanhoeffeni. Laackmanniella naviculaefera and Cy. convallaria forma cristallina were present at high abundance in both WW and SSWChl a>3. Upwelling caused discontinuity of the ciliate distribution. Our results will help predict the spatial and temporal variations of ciliate assemblages and other plankton according to the dynamics of water masses in Antarctic waters.

Most of previous studies in Amundsen Sea were in a relatively small latitude range with little information about tintinnid species composition and distribution. In the present study, we firstly investigated the tintinnid assemblages from Antarctic Zone (AZ) northward through Polar Front (PF) to Subantarctic Zone (SAZ). A total of 17 tintinnid species in 7 genera were collected and 16 of them were identified. Nine of them were Southern Ocean endemic species which mainly inhabited in AZ near Antarctic continent with abundance proportion exceeding 60% in total tintinnid. According to tintinnid abundance distribution, tintinnid species were attributed to four groups: Group I including Acanthostomella norvegica, Codonellopsis glacialis, Cd. pusilla and Cymatocylis antarctica mainly occurred in the north boundary of PF; Group II including Cymatocylis convallaria forma calyciformis, unidentified species and Amphorellopsis quinquealata mainly inhabited in PF; Group III including S. costata, Cy. vanhoeffeni, Cy. convallaria forma cristallina, Cy. convallaria forma drygalskii, Cy. convallaria, Cd. gaussi and L. naviculaefera mainly occurred in AZ near Antarctic continent; Group IV including Salpingella sp. inhabited in all zones. We found a new type (Group II) of tintinnid distribution characteristic in Polar Front and large lorica-oral-diameter (LOD) primarily inhabited in AZ. Meanwhile, we figured out distribution ranges of the tintinnid assemblages from AZ to PF and how the different assemblages mixed in PF. Our study could act as a typical example for a better understanding of tintinnid assemblages from Antarctic continent to Antarctic Circumpolar Current in Antarctic waters.

Average abundance and biomass of planktonic ciliate in seas near Antarctic Peninsula were 636 ± 936 ind./L and 2.57 ± 3.56 μg C/L, respectively. High values of ciliate abundance and biomass were mainly in the upper 50 m, but there was an obvious subsidence in Transect 2. Average abundance and biomass of tintinnid were 18 ind./L and 0.29 μg C/L, respectively. Tintinnid distribution patterns varied considerably in different transects. Tintinnid mainly occurred from surface to 300 m layer in the south of Transect 1. Tintinnid sank from surface in the north to 200 m in the south of Transect 2, while tintinnid in Transect 3 was on the contrary. In Transects 5 and 6, tintinnid mainly distributed in the surface layer. Aloricate ciliates were dominated in ciliate communities in study area, which determined total ciliates distribution pattern. Sixteen tintinnid species belong to 6 genera were identified, including 6 Southern Ocean endemic species. Neritic genus Tintinnopsis was occurred around Antarctic Peninsula. Sothern Ocean endemic species, which tended occurred in cold water, were dominant in this area. Cy. convallaria forma cristallina and Cy. convallaria were the most abundant species, their average abundances (maximum abundances) were 4.20 (74) ind./L and 4.15 (63) ind./L. In Principle Components Analysis, the first principle component was closely related to temperature, which had great influence on Southern Ocean endemic species, especially for Cy. convallaria forma cristallina and Cy. convallaria forma drygalskii. Cd. balechi, Cy. convallaria and L. naviculaefera had strongly negative correlations to total nitrogen, nitrate and silicate. The present study investigated planktonic ciliates in a relative complex habitat from Bransfield Strait, Weddell- Scotia confluence area to the South Orkney Islands, and figured out ciliate distribution situations in this area which provided valuable information for further study.

Language中文
Document Type学位论文
Identifierhttp://ir.qdio.ac.cn/handle/337002/156823
Collection海洋生态与环境科学重点实验室
Recommended Citation
GB/T 7714
梁晨. 南大洋不同海区浮游纤毛虫群落研究[D]. 中国科学院海洋研究所. 中国科学院大学,2019.
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