Nematodes are an important component of deep-sea hydrothermal vent communities, but only few nematode species are able to cope to the harsh conditions of the most active vent sites. The genus Oncholaimus is known to tolerate extreme geothermal conditions and high sulphide concentrations in shallow water hydrothermal vents, but it was only occasionally reported in deep-sea vents. In this study, we performed morphological, genetic and ecological investigations (including feeding strategies) on an abundant species of Oncholaimus recently discovered at Lucky strike vent field on the Mid-Atlantic Ridge at 1700 m water depth. We described this species as Oncholaimus dyvae sp. nov.. This new species differs from all other members of the genus by the combination of the following characters: body length (up to 9 mm), the presence of a long spicule (79 μm) with a distally pointed end, a complex pericloacal setal ornamentation with one precloacal papilla surrounded by short spines, and a body cuticule with very fine striation shortly posterior to the amphid opening. Overall, O. dyvae sp. nov. abundance increased with increasing temperature and vent emissions. Carbon isotopic ratios suggest that this species could consume both thiotroph and methanotrophic producers. Furthermore sulfur-oxidizing bacteria related to Epsilonproteobacteria and Gammaproteobacteria were detected in the cuticle, in the digestive cavity and in the intestine of O. dyvae sp. nov. suggesting a potential symbiotic association. This study improves our understanding of vent biology and ecology, revealing a new nematode species able to adapt and be very abundant in active vent areas due to their association with chemosynthetic micro-organisms. Faced by the rapid increase of anthropogenic pressure to access mineral resources in the deep sea, hydrothermal vents are particularly susceptible to be impacted by exploitation of seafloor massive sulfide deposits. It is necessary to document and understand vent species able to flourish in these peculiar ecosystems.

中文翻译：

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Oncholaimus dyvae sp。的生态和营养作用。十一月 （线虫：Oncholaimidae）来自幸运罢工热液喷口区（中大西洋海岭）

线虫是深海热液喷口群落的重要组成部分，但是只有很少的线虫能够应付最活跃的喷口部位的恶劣条件。已知Oncholaimus属可以耐受极端水热条件和浅水热液喷口中的高硫化物浓度，但仅在深海喷口中偶有报道。在这项研究中，我们对最近在大西洋中脊水深1700 m的幸运罢工喷口场发现的大量Oncholaimus物种进行了形态，遗传和生态研究（包括进食策略）。我们将此物种描述为Oncholaimus dyvae sp。nov ..该新物种与以下属的所有其他成员不同，它们具有以下特征的组合：体长（最大9毫米），存在长针尖（79μm），尖端朝远端，复杂的泪管周围装饰物，其中一个泪小管前乳头被短刺包围，并且身体的表皮在两栖动物开口后不久有非常细的条纹。总体而言，O。dyvae sp.。十一月 随着温度和排气孔排放的增加，丰度增加。碳同位素比值表明该物种可以消耗硫代营养型和甲烷营养型生产者。此外，在O.dyvae sp。的表皮，消化腔和肠中检测到与Epsilon变形杆菌和γ变形杆菌有关的硫氧化细菌。十一月 暗示潜在的共生关联。这项研究提高了我们对通风口生物学和生态学的理解，揭示了一种新的线虫物种，因为它们与化学合成微生物相关，因此能够在活动通风区域适应并非常丰富。面对深海获取矿产资源的人为压力的迅速增加，热液喷口特别容易受到海底大量硫化物矿床开采的影响。有必要记录和理解能够在这些独特的生态系统中繁衍的通风口物种。