Garren Melissa, Smriga Steven, Azam Farooq
Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, 8750 Biological Grade, Hubbs Hall, rm 4200, La Jolla, CA 92093-0202, USA.
Environ Microbiol. 2008 Sep;10(9):2299-312. doi: 10.1111/j.1462-2920.2008.01654.x. Epub 2008 Jun 28.
Coastal milkfish (Chanos chanos) farming may be a source of organic matter enrichment for coral reefs in Bolinao, Republic of the Philippines. Interactions among microbial communities associated with the water column, corals and milkfish feces can provide insight into the ecosystem's response to enrichment. Samples were collected at sites along a transect that extended from suspended milkfish pens into the coral reef. Water was characterized by steep gradients in the concentrations of dissolved organic carbon (70-160 microM), total dissolved nitrogen (7-40 microM), chlorophyll a (0.25-10 microg l(-1)), particulate matter (106-832 microg l(-1)), bacteria (5 x 10(5)-1 x 10(6) cells ml(-1)) and viruses (1-7 x 10(7) ml(-1)) that correlated with distance from the fish cages. Particle-attached bacteria, which were observed by scanning laser confocal microscopy, increased across the gradient from < 0.1% to 5.6% of total bacteria at the fish pens. Analyses of 16S rRNA genes by denaturing gradient gel electrophoresis and environmental clone libraries revealed distinct microbial communities for each sample type. Coral libraries had the greatest number of phyla represented (range: 6-8) while fish feces contained the lowest number (3). Coral libraries also had the greatest number of 'novel' sequences (defined as < 93% similar to any sequence in the NCBI nt database; 29% compared with 3% and 5% in the feces and seawater libraries respectively). Despite the differences in microbial community composition, some 16S rRNA sequences co-occurred across sample types including Acinetobacter sp. and Ralstonia sp. Such patterns raise the question of whether bacteria might be transported from the fish pens to corals or if microenvironments at the fish pens and on the corals select for the same phylotypes. Understanding the underlying mechanisms of effluent-coral interactions will help predict the ability of coral reef ecosystems to resist and rebound from organic matter enrichment.
菲律宾共和国博利瑙的沿岸遮目鱼（虱目鱼）养殖可能是珊瑚礁中有机物富集的一个来源。与水柱、珊瑚和遮目鱼粪便相关的微生物群落之间的相互作用，可以为生态系统对富集的反应提供见解。沿着一条从悬浮的遮目鱼养殖网箱延伸至珊瑚礁的样带在各个地点采集了样本。水样的特征是，溶解有机碳（70 - 160微摩尔）、总溶解氮（7 - 40微摩尔）、叶绿素a（0.25 - 10微克/升）、颗粒物（106 - 832微克/升）、细菌（5×10⁵ - 1×10⁶个细胞/毫升）和病毒（1 - 7×10⁷个/毫升）的浓度存在陡峭梯度，这些梯度与距鱼笼的距离相关。通过扫描激光共聚焦显微镜观察到，附着在颗粒上的细菌在梯度上从鱼笼处占总细菌的不到0.1%增加到5.6%。通过变性梯度凝胶电泳和环境克隆文库对16S rRNA基因进行分析，揭示了每种样本类型都有不同的微生物群落。珊瑚文库中代表的门数量最多（范围：6 - 8个），而鱼粪便中的数量最少（3个）。珊瑚文库中“新”序列的数量也最多（定义为与NCBI核苷酸数据库中的任何序列相似度<93%；占29%，而粪便文库和海水文库中分别为3%和5%）。尽管微生物群落组成存在差异，但包括不动杆菌属和罗尔斯通氏菌属在内的一些16S rRNA序列在不同样本类型中共同出现。这些模式引发了一个问题，即细菌是可能从鱼笼传输到珊瑚，还是鱼笼和珊瑚上的微环境选择了相同的系统发育型。了解废水与珊瑚相互作用的潜在机制将有助于预测珊瑚礁生态系统抵抗有机物富集并从中恢复的能力。
