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题名	南海陆架区束毛藻的丰度、分布及其调控因子研究; Abundance and distribution of Trichodesmium in the continental shelf waters of the South China Sea
作者	杨青
答辩日期	2014 ; 2009
导师	李少菁 ; 林元烧
关键词	束毛藻 丰度 分布 调控因子 南海陆架区 Trichodesmium Abundance Distribution Regulation factors Continental shelf of South China Sea
英文摘要	束毛藻（Trichodesmium）属于群体海洋固氮蓝细菌，主要分布于贫营养的亚热带和热带大洋，被认为是贫营养海区“新”氮的重要来源。它在我国近海（包括渤海、黄海、东海和南海）和沿岸水域都有一定数量的分布，甚至多次形成赤潮。当前对“陆架泵”（大气CO2吸收机制）研究的关注，大大增强了陆架区水域束毛藻的丰度、分布及固氮速率研究的重要性。 本文首次报道了南海陆架区（包括南海北部陆架区和北部湾东侧海域）束毛藻的丰度、水平和垂直分布模式，探讨了陆架区水域束毛藻丰度与分布的调控因子，旨在为陆架区以至中国海的束毛藻的生物量及其对固氮贡献的估算等提供参考依据。 主要成果如下： 1. 南海陆架区，束毛藻主要以单条藻丝（singletrichome）的形式存在，种类有：薛氏束毛藻（T.thiebautii）、汉氏束毛藻（T.hildebrandtii）和红海束毛藻（T.erythreaum）。 2. 北部湾东侧海域表层水体中，春季，束毛藻的平均丰度最高，为274条/升（变化范围为：0~3，510条/升）；秋季次之，为50条/升（变化范围为：0~212条/升）；夏季和冬季，平均丰度较低，夏季为29（变化范围为：0~196条/升），冬季为29条/升（变化范围为：0~356条/升）。南海北部陆架区表层水体中，春季，束毛藻的平均丰度为118条/升（变化范围为：0~670条/升）；夏季，平均丰度略高于春季，为241条/升（变化范围为：0~2，797条/升）。 3. 北部湾东侧海域表层水体中，束毛藻的水平分布模式与[NO3-+NO2-]、SRP的浓度（两者浓度变化趋势相同）有关。在[NO3-+NO2-]、SRP浓度的高值区，束毛藻的丰度均较低；四季，束毛藻丰度的高值区均分布在[NO3-+NO2-]和SRP浓度较低的区域。南海北部陆架区，在营养盐较高的珠江口水域和琼东沿岸上升流区，束毛藻丰度较低；在低营养盐的反气旋漩涡（19N，112E），束毛藻丰度最高，南海北部陆架区束毛藻的这种分布模式与北部湾东侧海域类似。 4. 北部湾东侧海域束毛藻的垂直分布模式为表层（1m）平均丰度最大。尽管，个别站位束毛藻丰度的最大层位于10m、30m甚至更深水层；但是，在束毛藻丰度相对较高（某一或几个水层丰度达到102条/升）的站位，束毛藻丰度的最大层多位于表层（1m）；这与以往在外海和大洋的研究结果（次表层，即10~40m层最大）有所不同。光强很可能是调控束毛藻垂直分布模式的主要因子。此外，[NO3-+NO2-]浓度也会影响束毛藻的垂直分布。若表层水中[NO3-+NO2-]浓度较高，而深层水中浓度较低，则束毛藻的丰度在深层水中较高，这与[NO3-+NO2-]对束毛藻的水平分布模式的调控相同。一些站位在50m以深水层出现较高丰度（1L水中有几十至上百条）的束毛藻，这些站位往往表层水中SRP的浓度较低，束毛藻的这种分布很可能与磷酸盐的获取有关。 5. 北部湾东侧海域表层水体，束毛藻的固氮速率，春季最高，约为521~4，083pgNL-1h-1；秋季仅次于春季，约为95~745pgNL-1h-1；冬季和夏季，均为55~432pgNL-1h-1；周年平均固氮速率为182~1，423pgNL-1h-1。南海北部陆架区表层水体中，春季束毛藻的固氮速率约为224~1，758pgNL-1h-1；夏季约为458~3，591pgNL-1h-1。 关键词：束毛藻；丰度；分布；调控因子；南海陆架区; Trichodesmium, a colonial marine cyanobacterium, is primarily distributed in oligotrophic tropical and subtropical oceans. Its cosmopolitan distribution and capacity to fix N2 make it an important contributor to the pool of new nitrogen in the oligotrophic oceans. It was also found in China Seas (including Bo Sea, Yellow Sea, East China Sea and South China Sea) and vicinity, and formed “algae bloom” in coastal waters frequently. The current focus on “continental shelf pump” (a mechanism for the absorption of atmospheric CO2) has elevated the importance of quantifying Trichodesmium abundance and nitrogen fixing rates in the continental shelf waters. Our research first reported Trichodesmium abundance and its distribution patterns in the continental shelf waters of South China Sea (including the continental shelf waters of northern South China Sea and eastern Beibu Gulf). The relationships between Trichodesmium abundance and ecological factors were discussed here in order to figure out the controlling factor(s) of Trichodesmium distribution. This will help to understand the role of Trichodesmium in the biogeochemical cycling and its importance of net sequestering of atmospheric CO2 in the continental shelf waters. The main results are as follows: 1. In the continental shelf waters of South China Sea, Trichodesmium mostly appeared in single trichome. Three species were identified, and they were Trichodesmium thiebautii, Trichodesmium hildebrandtii and Trichodesmium erythraeum. 2. In the surface waters of eastern Beibu Gulf, Trichodesmium was most abundant in spring, with the average density of 274 trichome L-1 (range: 0-3,510 trichome L-1). In autumn, Trichodesmium density was 50 trichome L-1 (range: 0-212 trichome L-1). And its densities were 29 (range: 0-196 trichome L-1) and 29 (range: 0-356 trichome L-1) trichome L-1 in summer and in winter, respectively. In the surface waters of continental shelf of northern South China Sea, Trichodesmium density was 118 trichome L-1 (range: 0-670 trichome L-1) in spring and 241trichome L-1 (range: 0-2,797 trichome L-1) in summer. 3. In the surface waters of eastern Beibu Gulf, the horizontal distribution of Trichodesmium abundance was related with nitrate and nitrite, SRP concentrations (which changed in the same trend). Low Trichodesmium abundance was observed in the areas with high nitrate and nitrite, SRP concentrations. And high Trichodesmium abundance mainly distributed in those areas with low nitrate and nitrite, SRP concentrations. In the continental shelf waters of north South China Sea, the nutrient are relative rich in the Zhujiang estuary and upwelling area along Qiongdong coast, where Trichodesmium abundance was low. By contrast, Trichodesmium was more abundant in the anticyclonic eddy (19 N, 112 E) where nutrient concentrations were especially low. 4. In the eastern Beibu Gulf, Trichodesmium abundance was highest at 1 m depth for those stations with relative high Trichodesmium densities (102 trichome L-1 in one or several water layers). A surface maximum of Trichodesmium density at 1 m depth was evident on all four cruises, which was different from the distribution pattern of Trichodesmium in the oceans (a subsurface maximum at 10-40 m). Light might be the main controlling factor of the vertical distribution of Trichodesmium. Besides, nitrate and nitrite concentrations also regulated Trichodesmium vertical distribution. High density of Trichodesmium appeared in the water layer with low nitrate and nitrite concentrations. At some stations, relative abundant (10-102 trichome L-1) Trichodesmium was found below 50 m depth. The SRP concentrations were usually low at these stations, thus this vertical distribution pattern of Trichodesmium was probably related with the acquisition of SRP. 5. In the surface waters of eastern Beibu Gulf, the nitrogen fixation rate by Trichodesmium was about 52-4,083 pg N L-1 h-1 in spring. And the rate was 95-745 pg N L-1 h-1 in autumn. In winter and summer, the nitrogen fixation rates were both 55-432 pg N L-1 h-1. The annual average nitrogen fixation rate was 182-1,423 pg N L-1 h-1. In the surface waters of continental shelf of northern South China Sea, the nitrogen fixation rates were 224-1,758 and 458-3,591 pg N L-1 h-1 in spring and summer, respectively. Key words: Trichodesmium; Abundance; Distribution; Regulation factors; Continental shelf of South China Sea; 学位：理学博士; 院系专业：海洋与环境学院海洋学系_海洋生物学; 学号：22420060153346
语种	zh_CN
出处	http://210.34.4.13:8080/lunwen/detail.asp?serial=24524
内容类型	学位论文
源URL	[http://dspace.xmu.edu.cn/handle/2288/76706]
专题	海洋地球－学位论文
推荐引用方式 GB/T 7714	杨青. 南海陆架区束毛藻的丰度、分布及其调控因子研究, Abundance and distribution of Trichodesmium in the continental shelf waters of the South China Sea[D]. 2014, 2009.

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