大型藻类在工程治理海水富营养化和抑制病原微生物中的作用

IOCAS-IR > 海洋环流与波动重点实验室

	大型藻类在工程治理海水富营养化和抑制病原微生物中的作用
其他题名	The Effect of Macroalgae on Removing Eutrophication of Seawater in Engineering and Inhibiting Pathogeny Germ
	路克国
学位类型	博士
	2008-06-12
学位授予单位	中国科学院海洋研究所
学位授予地点	海洋研究所
关键词	大型藻类富营养化鳗弧菌
摘要	沿海工农业生产的快速发展和人类活动对近海生态系统产生了很大影响，大量化肥的使用和工业污水、生活污水的排放导致近海环境污染，海水富营养化，赤潮频发。另外，由于近海养殖活动的迅猛发展以及养殖的不规范和不科学性导致近海生态系统结构和功能改变，一方面加重了海水富营养化，另一方面养殖动植物病害经常发生，严重影响了海产品的质量和效益。大型海藻是海区重要的初级生产者，生命周期长、生长快，能通过光合作用吸收固定水体的C、N、P等营养物质来合成自身，同时增加水体溶解氧。因此，大型海藻被称为海洋环境中的生物过滤器。另外，由于大型藻类自身营养成分的复杂性和与藻共生的微生物多样性，大型海藻还可对生态系统中的浮游生物和微生物产生直接和间接影响。在海洋环境，尤其是海水养殖水体环境存在着两个主要问题：海水富营养化和病源微生物控制，本文针对海洋环境中存在的这两个问题进行了探索研究。以大型经济藻种长心卡帕藻（Kappaphycus alvarezzi）作为实验材料，分别在实验室内、室外藻类处理系统和海湾养殖现场三种条件下，进行藻类去除海水氮磷的一次性实验、半连续实验和连续实验，研究了其对海水中无机氮、无机磷的吸收速率和去除能力，初步评估了其生态价值。构建了一种半封闭海域富营养化治理模式，以长心卡帕藻为实验材料，研究了其去除海水富营养化的能力，主要结果如下：（1）室内实验研究发现，长心卡帕藻对氮、磷的吸收速率随底物浓度升高而升高。在氮磷比为10:1，温度28℃条件下，氮浓度为50μmol • L-1时，藻对氮、磷的吸收速率达到最大，分别为0.93µmol • g-1（FW）• h-1和0.072µmol • g-1（FW）• h-1。（2）人工修建的藻类养殖系统中进行的长心卡帕藻去除氮、磷的半连续实验，结果表明该藻具有连续去除海水DIN、DIP的能力。只要保持足够的底物浓度，长心卡帕藻对无机氮、无机磷的吸收速率达到最大，分别为0.3µmol • g-1（FW） • h-1和0.03µmol • g-1（FW）• h-1。但是对氮磷的吸收速率较室内实验有所降低。（3）自然条件下，通过调查黎安海湾水质情况发现，长心卡帕藻具有较大的生态效益。在整个海湾大面积养殖卡帕藻，通过收获藻体，每年大约可以从海水中带走33吨氮素，7.5吨磷素。由于在海湾长心卡帕藻的作用，全年海湾水质保持在1-2级国家海水质量标准，产生了明显的生态效益。另外，我们对大型藻类浒苔（Ulva clathrata）吸收氮磷和抑制鳗弧菌（Vibrio anguillarum）的效果进行了初步探索，结果表明：浒苔不仅对培养系统内无机氮和磷具有明显的去除作用，而且在异养细菌总量没有降低的情况下，对鳗弧菌有显著抑制作用，该抑制作用还受到水体中氮磷营养盐浓度的影响。在10g • L-1海藻的条件下，鳗弧菌以105－107 cfu • mL-1接入2天后，无论是否添加外源氮磷，鳗弧菌密度降到10 cfu • mL-1以下，鳗弧菌去除率几乎达到100%。实验数据还显示，添加氮磷营养盐可以增强浒苔对鳗弧菌的抑制作用，但没有降低其中的异养菌群数量，系统内异养细菌总量均维持在较高水平。进一步研究表明，培养浒苔24h后的海水，也对鳗弧菌65#产生抑制作用，这说明浒苔代谢释放到水体中某种化学成分或与藻共栖的微生物对鳗弧菌生长产生了抑制。
其他摘要	The rapid development of industry and agriculture and human activities had caused great effect on marine ecosystem. Abuse of chemical fertilizer and the drainage of sewage polluted the seawater and made it eutrophicated, so the red tide occurred frequently. Recently, marine aquacultures develop too fast but without scientific management. This affects seriously the coastal marine ecosystem. The eutrophication becomes more and more serious and diseases of cultural animals often happen. How to deal with eutrophication and marine animals’ diseases in coastal areas is an urgent issue for sustaining a healthy coastal ecosystem. Macroalgae is an important primary producer with a long life and fast growing speed. It can absorb many nutrients such as C, N, and P etc. in the seawater through photosynthesis and increase the concentration of dissolved O2 in the water body. Therefore, macroalgae is regarded as a bio-filter in marine ecosystem. In addition, macroalgae has direct or indirect effect on the plankton and microorganisms in the seawater. There exist two serious problems （eutrophication and pathogeny germ control） in now marine environment, especially in the marine aquaculture seawater. Some researches were carried out in this study according to the two problems. Because of different climate and condition between North China and South China, two typical macroalgae Kappaphycus alvarezzi and Ulva clathrata were selected as experimental materials. The nutrients removing experiments were done in the laboratory, in the algae cultural system and under the natural condition respectively. N and P uptake rates of K. alvarezii at different conditions were detected and the ecological value of K. alvarezii was evaluated. An eutrophication removing model was designed in a semi-closed bay. The abilitiy of K. alvarezii in removing N and P of eutrophicated seawater was studied and the results were as follows: 1） In the laboratory, N and P uptake rates of K. alvarezii increased with the increase of N and P concentration. At the N concentration 50μmol • L-1, N and P uptake rates reaches the maximums in 28℃ with the N/P ratio 10. The N and P maximal uptake rates were 0.93µmol • g-1（FW）• h-1 and 0.072µmol • g-1（FW）• h-1. 2） The algae culture system was constructed in a big pool outdoor near the sea. The semi-continuous experiment of nutrients removing by algae was conducted. The results showed that K. alvarezii could removing N and P continuously from seawater. The N and P uptake rates by the alga always stayed a highest level 0.3µmol • g-1（FW）• h-1 and 0.03µmol • g-1（FW）• h-1 if the substrate concentration was enough. 3） Under natural condition, the N and P removing by K. alvarezii was inspected yearly in Li’an Bay, Hainan province. K. alvarezii contributed a lot to the purification of the seawater. In this bay, K. alvarezii was a dominant alga. Every year, about 33t nitrogen and 7.5t phosphorus was removed from the bay by harvesting the alga body. The water quality of Li’an Bay now stayed at 1 or 2 grade of national standard. Therefore, culturing K. alvarezii had great contribution to marine environment protection. The effect of Ulva clathrata on inhibiting Vibrio anguillarum was primarily studied. The results showed that Ulva clathrata not only could remove large amount of N and P from the culture system, but also had striking suppressive effect on Vibrio anguillarum without reduce of the total amount of bacteria. The suppressive effect was disturbed by the concentration of nitrogen and phosphorus in the culture seawater. In the experiments, with the algae density 10 g • L-1 and the initial inoculation concentration of vibrio 105~107 cfu • mL-1, the vibrio density dropped under the level of 10 cfu • mL-1 after 2 days whether the external N and P were added or not. The algae Ulva clathrata removed almost all of the vibrio in the culture medium. The results also indicated that adding N and P could enhance the repressive effect the algae had on the vibrio, but did not reduce the amount of bacteria cluster. The total amount of bacteria in the cultural system was in a high level at all the time.
页数	91
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/243
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	路克国. 大型藻类在工程治理海水富营养化和抑制病原微生物中的作用[D]. 海洋研究所. 中国科学院海洋研究所,2008.

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