【作者】 林丽贞；

【导师】 黄邦钦；

【作者基本信息】 厦门大学 ， 环境科学， 2007， 硕士

【摘要】 2005年与2006年夏季,对台湾海峡南部受到上升流影响的海区进行了2个航次的跟踪调查。主要通过检测群落水平和单细胞水平碱性磷酸酶活性来指示该海区的磷胁迫状况,同时,通过追踪上升流形成、发展的过程来探讨上升流过程对浮游植物磷胁迫的影响。主要实验结果如下:1.从大面站结果来看,尽管2005年7月的上升流强度要明显强于2006年6月航次,但在整个海区的磷胁迫程度上,2005年7月要大于2006年6月,2005年7月碱性磷酸酶活性变化范围为11.1~143.4nmol l-1 h-1,平均值为44.7±41.2 nmol l-1 h-1;2006年6月近岸站位APA略高于20 nmol l-1 h-1,而浅滩区和外海区则小于10 nmol l-1 h-1。2.上升流形成对于中心区上层浮游植物的磷胁迫有明显的缓解作用,当上升流减弱后,由于浮游植物的生长导致DIP的消耗,进而再度进入磷胁迫状态,随着DIP的持续消耗浮游植物的生长受到磷限制,最后大量死亡。在没有上升流的海区,浮游植物持续处于磷胁迫的状态,由于没有营养盐的输入而诱发水华发生,因此受磷胁迫的程度反而较轻。陆地迳流也会对近岸海区的磷胁迫产生一定程度的缓解;大风导致的海水搅动在一定程度上缓解了上层水体的磷胁迫状态。3.船基围隔实验的结果表明,不论是低添加组还是高添加组,实验初期都能缓解水体的磷胁迫;但到培养后期,低添加组的磷胁迫程度会超过高添加组。控制组的磷胁迫程度在三个组中是最大的。4.在空间尺度上,浮游植物种类变动与其碱性磷酸酶的表达能力无明显相关性。而上升流跟踪实验中发现,时间尺度上仅有在台湾海峡占绝对优势的拟菱形藻与其表达碱性磷酸酶的能力存在显著相关,说明在同样的磷胁迫状态下,拟菱形藻的数量变动很大程度上决定于其表达碱性磷酸酶以缓解磷胁迫的能力上。这有可能是该属占绝对优势的主要原因。更多还原

【Abstract】 Two cruises were carried out to study phosphorus stress of phytoplankton in southern Taiwan Strait in summer during 2005-2006, which upwelling induced by the monsoon. By using bulk and single cell alkaline phosphatase activity (APA) assay, phosphorus stress was studied via mapping, algal bloom process and ship-based mesocosm, the main results were as follows:1. The data from mapping showed that phytoplankton suffered more severe phosphorus stress in July 2005 than that in June 2006 although the upwelling was stronger in July 2005 than that in June 2006. The surface APA ranged 11.1~143.4nmol l-1 h-1, with mean of 44.7±41.2 nmol l-1 h-1 in July 2005, while there was higher than 20nmol l-1 h-1 for coastal waters and lower than 10 nmol l-1 h-1 for the bank, and offshore areas in June 2006.2. It obviously declined phosphorus stress of phytoplankton in upwelling area due to nutrient input induced by the upwelling. Then the bloom happened and accompanied with phosphorus declined. When the upwelling weakened and phosphorus absorbed by phytoplankton exceed supplement by upwelling, phytoplankton suffered phosphorus stress again. Then the stress was aggravated and truned into phosphorus limitation. Phytoplankton stayed in the status of phosphorus stress continuously and kept the balance when there was no or weak bloom happened. So the status of phosphorus in June 2006 would not be more severe than that in July 2005 when there had an intense upwelling. The mixture of the upper and bottom waters because of the disturbing by the heavy wind would bring the phosphorus to the upper water and it could decline phosphorus stress in some degree.3. Results of the mesocosm experiment showed that, phosphorus stress was mitigated both in the lower and the higher nutrient supply groups at the beginning of the incubation. In the ending of the experiment, the degree of phosphorus stress was more serious in lower nutrient supply group than that in the higher nutrient supply group. The control group suffered the most severe phosphorus stress.4. There was not significantly relationship between phytoplankton species succession and phosphorus stress in spatial scale in the study area. In temporal scale, there was significantly relationship between dominant species Pseudonitzschia spp. and the ability in synthesizing the AP. It meant that its variation of abundance relied on its ability in synthesizing AP to avoid phosphorus limitation in same degree of status of phosphorus stress compare to other species. It might be the reason for Pseudonitzschia spp. to be dominanted species in the Taiwan Strait更多还原