Species within the genus Alcanivorax are well known hydrocarbon-degraders that propagate quickly in oil spills and natural oil seepage. They are also inhabitants of the deep-sea and have been found in several hydrothermal plumes. However, an in-depth analysis of deep-sea Alcanivorax is currently lacking. In this study, we used multiple culture-independent techniques to analyze the microbial community composition of hydrothermal plumes in the Northern Tonga arc and Northeastern Lau Basin focusing on the autecology of Alcanivorax. The hydrothermal vents feeding the plumes are hosted in an arc volcano (Niua), a rear-arc caldera (Niuatahi) and the Northeast Lau Spreading Centre (Maka). Fluorescence in situ hybridization revealed that Alcanivorax dominated the community at two sites (1210–1565 mbsl), reaching up to 48% relative abundance (3.5 × 10⁴ cells/ml). Through 16S rRNA gene and metagenome analyses, we identified that this pattern was driven by two Alcanivorax species in the plumes of Niuatahi and Maka. Despite no indication for hydrocarbon presence in the plumes of these areas, a high expression of genes involved in hydrocarbon-degradation was observed. We hypothesize that the high abundance and gene expression of Alcanivorax is likely due to yet undiscovered hydrocarbon seepage from the seafloor, potentially resulting from recent volcanic activity in the area. Chain-length and complexity of hydrocarbons, and water depth could be driving niche partitioning in Alcanivorax.

Alcanivorax属的物种是众所周知的碳氢化合物降解者，在漏油和自然石油渗漏中快速繁殖。它们也是深海的居民，在一些热液羽流中被发现。然而，目前缺乏对深海食食狼鱼的深入分析。在这项研究中，我们使用多种独立于培养的技术来分析北汤加弧和东北劳盆地热液羽流的微生物群落组成，重点关注食食狼菌的自生生态。供给羽流的热液喷口位于弧火山 (Niua)、弧后破火山口 (Niuatahi) 和东北劳扩散中心 (Maka)。荧光原位杂交显示Alcanivorax在两个位点 (1210-1565 mbsl) 的群落中占主导地位，相对丰度高达 48% (3.5 × 10 ^{4 个}细胞/ml)。通过 16S rRNA 基因和宏基因组分析，我们确定这种模式是由Niuatahi 和 Maka 羽流中的两种Alcanivorax物种驱动的。尽管没有迹象表明这些区域的羽流中存在碳氢化合物，但观察到参与碳氢化合物降解的基因的高表达。我们假设Alcanivorax的高丰度和基因表达可能是由于尚未发现的海底碳氢化合物渗漏造成的，这可能是该地区最近的火山活动造成的。碳氢化合物的链长和复杂性以及水深可能是Alcanivorax中生态位划分的驱动因素。