| 摘要: |
| 2008 年夏季东南亚地区栽培的产卡拉胶海藻麒麟菜类陆续发生冰样白化病害并造成大规模死亡。本文根据作者近年来的观测和实验数据探讨了产生该现象的环境因素, 通过重演性实验验证和比较了不同株系抗病力差异。结果表明: 1) 不同海菜株系的抗病能力差异很大, 从印度尼西亚引进株系比从菲律宾引进株系抗病能力强, 其中株系5 抗病能力最强, 没有发生冰样白化病症; 株系4、6 和11 的抗病能力次之, 只在10%以下的藻株出现病害症状, 日生长速率在7%以上的高水平;株系7、8 和9 号病害损伤程度是印度尼西亚引进株系中最为严重的, 但比原产菲律宾海菜要轻。2)与往年同期气象数据相比, 在病害发生期间光照时间短、强度弱、海水温度高、降雨量多、蒸发量少、海水盐度下降, 上述变化明显不能满足热带产胶海藻生长所需要环境条件, 导致了海菜生理状况和生长速率下降。3) 从海湾内海菜发病分布和死亡程度上, 越远离海湾口和偏离主航道、水浅流速小区域所栽培的海菜发病越早、死亡也越严重; 相反, 在靠近湾口与外海具有较好水交换和离航道近、水深流速大的区域, 海菜发病相对较晚。4) 重演实验证实, 将海菜浸泡在盐度28 的海水中2h, 1 天后部分株系就会出现冰样白化病症, 3 天后藻体软化而死亡; 海菜浸泡在22 盐度的海水2h,会导致更多株系的海菜发生严重的白化病害并死亡。上述结果表明, 过多降雨所导致的海水盐度下降是诱发热带产胶海藻爆发大面积病害发生和死亡的主要原因。
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| 关键词: 麒麟菜, 长心卡帕藻, 产胶海藻, 冰样白化病 |
| DOI：10.11693/hyhz200902020020 |
| 分类号: |
| 基金项目:国家海洋行业公益性科研专项资助, 200705010 号; 国家自然科学基金项目资助, 30771638 号 |
附件 |
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| THE REASONS CAUSING CATASTROPHIC DEATH IN TROPICAL CARRAGEENAN PRODUCING SEAWEEDS AND THEIR DIFFERENCE IN RESISTANCE TO ILLNESS |
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LIU Jian-Guo1, PANG Tong1, WANG Li1,2, LI Jun1,2, LIN Wei1
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1.Institute of Oceanology, Chinese Academy of Sciences;2.Marine College, Hainan University
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| Abstract: |
| A large scale of ice-ice disease burst out and caused catastrophic death in tropical carrageenan producing seaweeds like eucheumatoid and Kapaphycus species in Southeast Asia during the summer of 2008. The resistances of 12 strains collected from different countries were studied by calculating the incidence of ice-ice disease in Li’an Bay, Hainan, China. The main reasons causing the catastrophic death were analyzed by comparing our measured data during the ice-ice disease outbreak season in 2008 with the same period in 2004. Then, a paleogenetic experiment was carried out to verify the concluded reason for the catastrophic death.
The results show that the disease resistance of different strains varied widely, that all the strains originally collected from Indonesia had higher resistance than the Philippine strains. Of all the strains tested, strain 5 showed the best growth behavior without any symptom of ice-ice disease followed by strains 4, 6, and 11 with <10% incidence of ice-ice symptom. The daily specific growth rates (SGR) of strains 5, 4, 6 and 11 varied from 7% to 9%. All the Philippine strains cultured in Hainan Island were died during the disease burst out period.
Meteorological data indicated an obvious climatic change like short illumination time, low light intensity, relative high seawater temperature, strong rainfall and low evaporation, as well as low seawater salinity during the disease outbreak period, which could not meet the normal growth of carrageenan producing eucheumatoid and Kapaphycus, and caused low SGR and poor physiological status.
In terms of distribution of ice-ice disease and the death status inside bay, we found that the farther the seaweed culture area from the bay-mouth and the deep principal channel, the earlier the incidence of disease outbreak and the higher the mortality rate. On the contrary, the seaweed cultured in the place near to the bay-mouth or to the main channel with high current and abundant water exchange had relatively low symptom of ice-ice disease. The paleogenetic experiment indicate that after soaking in seawater of 28 salinity for 2 hours, part of the tested strains become illness within 1 day and dead in 3 days, besides more strains were sick and dead while they exposed to seawater of 22 salinity for 2 hours. Based on the above results, we concluded that low seawater salinity caused by excessive rainfall is the main reason for the large scale outbreak of ice-ice disease and the catastrophic death in carrageenan producing seaweed.
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| Key words: Eucheumatoid, Kappaphycus, Carrageenan producing seaweed, Ice-ice disease |
