Benthic microbial indicators of fish farm impact in a coastal area of the Tyrrhenian Sea
Benthic microbial indicators of fish farm impact in a coastal area of the Tyrrhenian Sea
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DOI：
10.1016/s0044-8486(03)00433-2
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发表时间：
2004-02-16
期刊：
影响因子：
4.5
通讯作者：
Maugeri, TL
中科院分区：
文献类型：
--
作者：
La Rosa, T;Mirto, S;Maugeri, TL
我们研究了有机负荷的影响，由于在第勒尼安海（西地中海）的非受影响的沿海地区的养鱼场的生物沉积。1997年7月至1998年2月，在两个站位（一个位于养鱼场下方，另一个位于约1 km外，作为参考点）每月调查沉积物化学和底栖微生物群落。网箱的存在引起了底栖条件的迅速变化：沉积物迅速（6周后）减少。在最初的网箱部署后2周，在未受影响的沉积物上，以及5-7个月后，在网箱下方观察到生物聚合物碳的显著积累，并且似乎与养鱼场生产周期有关。养鱼场下方的微生物群落密度仅在养殖活动的第一个月（7月）和部分7个月后的笼子处置（即1月），当有一个显着的沉积物有机富集增加。自发荧光微生物细胞数量的增加提供了养鱼场对底栖细菌群落迅速影响的其他证据。光合作用的真核细胞表现出高度减少的贡献，总的自发荧光的微生物密度，这表明它们的减少与生物聚合物碳积累，可能是由于也是由于“阴影效应”诱导的悬浮物，来自渔场，对下面的环境。在这里，我们建议，适用于可培养的异养细菌的微生物直接计数（CFU/MDC）的比率来检测养鱼场的影响。在笼沉积物中，有机富集和随之而来的修改的底栖环境的特点，确定了增加好氧异养细菌和弧菌密度表明，他们是有效的殖民者的有机丰富的沉积物。大肠埃希菌和肠球菌的密度并不显著高于参考点，可能是陆地来源。因此，它们不能用作养鱼场影响的具体指标。(C)2004 Elsevier B. V.保留所有权利。
We studied the impact of organic loads due to the biodeposition of a fish farm in a non-impacted coastal area of the Tyrrhenian Sea (Western Mediterranean). Sediment chemistry and benthic microbial community were investigated from July 1997 to February 1998 on monthly basis at two stations: one was located under the fish farm, while the second was about 1 km away, and served as a reference site. The presence of the cage induced rapid changes in the benthic conditions: the sediments were rapidly (after 6 weeks) reduced. A significant accumulation of biopolymeric carbon was observed beneath the cage both 2 weeks after the initial cage deployment, on non-impacted sediments, and 5-7 months after, and appeared to be related to the fish farm production cycle. The density of microbial communities beneath the fish farm increased only during the first month of farming activity (July) and partially 7 months after cage disposal (i.e. in January), when there was a significant sediment organic enrichment. Additional evidence of rapid impact of the fish farm on the benthic bacterial communities is provided by the increase in the numbers of autofluorescent microbial cells. The photosynthetic eukaryotic cells displayed a highly reduced contribution to total autofluorescent microbial density, indicating that their decrease is related with biopolymeric carbon accumulation, and probably was due also to "shadow effect" induced by suspended material, coming from the fish farm, on the environment below. We propose here, to apply the ratio of culturable heterotrophic bacteria to microbial direct counts (CFU/MDC) to detect fish farm impact. In cage sediments, organic enrichment and the consequent modification of the characteristics of the benthic environment, determined an increase in aerobic heterotrophic bacteria and vibrio density indicating, that they are efficient colonizers of organic-rich sediments. Densities of Escherichia coli and Enterococci were not significantly higher than in the reference site, and are likely of terrestrial origin. Thus they cannot be used as specific indicators of fish farm impact. (C) 2004 Elsevier B.V. All rights reserved.