| 摘要: |
| 采用实验室模拟的方法, 研究了不同海水温度、盐度、pH、N/P比下, 沙海蜇消亡过程中海水溶解氧的变化特征, 这对探讨水母灾害性暴发后消亡的环境影响有重要的科学意义。研究结果表明, 沙海蜇的消亡可引起海水溶解氧浓度的显著降低, 不同海水温度、盐度、pH、N/P比条件下沙海蜇消亡引起的海水溶解氧浓度的降低无显著差异, 但与没有沙海蜇消亡时, 海水溶解氧的变化相比则差异显著。沙海蜇消亡一般需要6—7天时间, 在高N/P比的海水中, 沙海蜇的消亡时间延长。沙海蜇的消亡造成水体的严重缺氧, 水体氧饱和度低于20%, 从第2天到第3天, 本底海水、不同过程温度、盐度、pH条件下, 消耗水体氧的量剧增, 第6天达到峰值, 但不同N/P比条件下, 水体溶解氧降低在第2天即可达到一个耗氧的高值, 一直持续到第7天出现峰值; 海水温度、盐度、pH、N/P比变化, 可导致沙海蜇的消亡过程中水体氧消耗量的变化, 就这四种影响因素而言, 其平均最大耗氧量从大到小的顺序是: 温度(23—30℃区间段) > pH(5.0—9.0区间段) > 盐度(21—33区间段) > N/P比(16:1—240:1区间段), 分别为39.9、39.7、38.0和35.9mg/(kg·d), 相对而言, 水体温度和pH对沙海蜇消亡过程中氧消耗量影响较大, 水体N/P比和盐度影响较小。所以, 沙海蜇消亡过程中, 由于海水温度和pH的变化形成的低氧区更为严重, 而且在当今富营养化(高N/P比)的近海水域中, 水母的消亡高耗氧的时间加长, 对海水环境造成的影响更为严重。 |
| 关键词: 溶解氧, 环境影响, 消亡过程, 沙海蜇, 模拟研究 |
| DOI：10.11693/hyhz201203015015 |
| 分类号: |
| 基金项目:国家重点基础研究发展计划(973)项目, 2011CB403602 号, “海洋环境变化与水母暴发的相互作用”; 国家自然科学基金委员会创新群体项目资助, 41121064 号 |
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| SIMULATION OF DISSOLVED OXYGEN(DO) VARIATIONS DURING THE DECOMPOSITION PROCESS OF NEMOPILEMA NOMURAI |
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SONG Jin-Ming1, MA Qing-Xia1,2, LI Ning1, LI Xue-Gang1, YUAN Hua-Mao1, DUAN Li-Qin1, QU Bao-Xiao1,2
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1.Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanography, Chinese Academy of Sciences;2.Graduate University of Chinese Academy of Sciences
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| Abstract: |
| To understand the influence of the decaying process after a large jellyfish bloom on marine environment, laboratory simulation experiments were performed to study the variations of dissolved oxygen (DO) during the decompo-sition process of Nemopilema nomuraiat different temperature, pH, salinity, and N/P ratios. The results suggested that the decomposition of N. nomuraineeded a great deal of oxygen, and the extents of DO decrease were not significantly differ-ent under different temperature, pH, salinity, and N/P ratio conditions. Complete decomposition of N. nomuraigenerally took about 6—7 days and more time was needed under high N/P conditions. The decomposition of N. nomuraicaused se-vere hypoxia of the seawater and the oxygen concentration was below 20% of saturation. Oxygen consumption in the simulation experiments dramatically increased from the second day to the third day and it peaked on the sixth or the sev-enth day. However, the high DO consumption rates under different N/P conditions appeared in the second day and contin-ued to the seventh day. Different temperature, salinity, pH and N/P ratios in the seawaters caused variations in the extents of DO consumption during the decomposition process. The extents of DO consumption were in the order of temperature (23—30℃) > pH (5.0—9.0) > salinity (21—33) > N/P ratio (16:1—240:1), and the values of 39.9, 39.7, 38.0, and 35.9 mg/(kg·d), respectively. Consequently, the influence of temperature and pH on the DO consumption was more significant and the influence of N/P ratio and salinity was relatively small. |
| Key words: Dissolved oxygen (DO), Marine environment factors, Decomposition Nemopilema nomurai, Simulation test |
