Fluorescence sensors mounted on unmanned underwater gliders open new ways of investigation to detect dissolved hydrocarbons in seawater. A glider was deployed for 20 days to monitor biogeochemical and physical signals associated with natural hydrocarbon seepages within the first 700 m in the Angolan waters. The glider was equipped with fluorometers (MiniFluo-UV) to measure the concentrations of polycyclic aromatic hydrocarbons (PAH) of interest, i.e. naphthalene, phenanthrene, fluorene and pyrene. A continuous PAH-like signal detected within the 70 m layer below the sea surface is associated with high chlorophyll concentration in the deep chlorophyll maximum. Vertical PAH-like anomalies forming either strong spikes or diffuse columns down to 700 m are observed at the exact location of oil seep sites identified on Synthetic Aperture Radar satellite images. An ~200 m thick layer of enhanced PAH-like concentration, topped by a thermo/pycnocline identified at 280–300 m water depth, is measured in concomitance with the decrease in oxygen concentration. The concomitance of these signals suggests that lower oxygen concentrations induce a preservation of hydrocarbons within the eastern Atlantic oxygen minimum zone. Even if the absence of in-situ measurements limits the understanding of physical and biogeochemical processes affecting PAH concentrations, the measurements conducted at the edges of the OMZ suggests a relationship with microbial activity and organic matter dynamics in this layer. The results presented here show that gliders equipped with PAH sensors represent a promising means for monitoring hydrocarbons in the oceans, especially when they are coupled with other systems (i.e. Synthetic Aperture Radar).

安装在无人水下滑翔机上的荧光传感器开辟了检测海水中溶解碳氢化合物的新方法。部署了 20 天的滑翔机，以监测与安哥拉水域前 700 m 内天然碳氢化合物渗漏相关的生物地球化学和物理信号。滑翔机配备有荧光计 (MiniFluo-UV) 以测量目标多环芳烃 (PAH) 的浓度，即萘、菲、芴和芘。在海面以下 70 m 层内检测到的类似 PAH 的连续信号与深层叶绿素最大值中的高叶绿素浓度有关。在合成孔径雷达卫星图像上确定的石油渗漏点的确切位置观察到形成强尖峰或扩散柱的垂直 PAH 类异常现象，该异常形成深达 700 m。随着氧浓度的降低，测量到约 200 m 厚的增强类 PAH 浓度层，其顶部是在 280-300 m 水深处确定的热/偏斜层。这些信号的伴随表明较低的氧气浓度会导致东大西洋氧气最低区内碳氢化合物的保存。即使没有原位测量限制了对影响 PAH 浓度的物理和生物地球化学过程的理解，在 OMZ 边缘进行的测量表明与该层中的微生物活动和有机物质动力学有关。