Microbial status in seawater and coastal sediments during pre- and post-tsunami periods in the Bay of Bengal, India
Microbial status in seawater and coastal sediments during pre- and post-tsunami periods in the Bay of Bengal, India
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印度孟加拉湾海啸前后海水和沿海沉积物中的微生物状况
DOI：
10.1111/j.1439-0485.2006.00110.x
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
N. Mathivanan
中科院分区：
文献类型：
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作者：
S. Ramesh;M. Jayaprakashvel;N. Mathivanan
海啸是2004年12月26日发生在印度洋的自然灾害，给沿海地区的人类造成了严重的破坏。各机构估计了这次灾难造成的总生命损失和经济损失，但尚未探讨其对微生物密度的影响。根据我们之前对海啸前印度孟加拉湾金奈海岸四个地点的微生物种群的研究结果，海啸后在同一地点定期研究微生物种群的变化。海啸发生后5-10小时，在四个不同地点采集海岸沉积物和海水样本，此后每隔7天采集一次，直至28天。通过在不同培养基上的连续稀释，从海洋样品中分离出细菌、真菌和放线菌。海啸发生前，海水样品中的细菌数量高于沉积物，而真菌和放线菌仅在沉积物中记录。海啸后5-10小时，所有海洋样本的微生物数量都显著增加，而与地点无关。然而，在随后的几天里，它慢慢下降，并变得与海啸前记录的人口相似。海啸后革兰氏阳性菌数量增加，革兰氏阴性菌数量减少。此外，大肠菌群和弧菌等致病菌的数量在海啸后没有增加。据观察，即使在海啸发生28天后，细菌和放线菌的数量仍在增加，这可能是由于外来微生物的引入，这些微生物通过表现出色素沉着和产生外多糖等特殊特征，发展了在极端环境中生存的能力。
Tsunami, the natural disaster, which occurred on December 26, 2004 in the Indian Ocean, caused severe damage to mankind in the coastal areas. Total loss of life and economic loss because of this disaster have been estimated by various agencies but its effect on microbial density has not been probed. With our previous results on microbial populations in four locations of the Chennai coast of the Bay of Bengal, India in the pre-tsunami period, the change in microbial populations was studied after the tsunami at regular intervals in the same locations. Coastal sediment and seawater samples were collected from four different locations after 5–10 h and thereafter at intervals of every 7 days up to 28 days post-tsunami. Bacteria, fungi and actinomycetes were isolated from the marine samples by serial dilution on respective media. Before the tsunami, the bacterial population was higher in seawater samples than the sediments, whereas fungi and actinomycetes were recorded only in the sediments. The microbial population remarkably increased 5–10 h post-tsunami in all the marine samples irrespective of the location. However, it slowly declined in the subsequent days and became similar to that of the population recorded before the tsunami. The population of gram-positive bacteria increased whereas the gram-negative bacterial population decreased after the tsunami. Further, populations of pathogenic bacteria such as coliform and vibrios did not increase after the tsunami. It has been observed that the increase in populations of bacteria and actinomycetes even after 28 days of tsunami may be due to the introduction of foreign microorganisms that developed the ability to survive in the extreme environment by exhibiting special characteristics such as pigmentation and production of exopolysaccharides.