Data from: Marine communities on oil platforms in Gabon, West Africa: high biodiversity oases in a low biodiversity environment

The marine biodiversity of Gabon, West Africa has not been well studied and is largely unknown. Our examination of marine communities associated with oil platforms in Gabon is the first scientific investigation of these structures and highlights the unique ecosystems associated with them. A number of species previously unknown to Gabonese waters were recorded during our surveys on these platforms. Clear distinctions in benthic communities were observed between older, larger platforms in the north and newer platforms to the south or closer to shore. The former were dominated by a solitary cup coral, Tubastraea sp., whereas the latter were dominated by the barnacle Megabalanus tintinnabulum, but with more diverse benthic assemblages compared to the northerly platforms. Previous work documented the presence of limited zooxanthellated scleractinian corals on natural rocky substrate in Gabon but none were recorded on platforms. Total estimated fish biomass on these platforms exceeded one ton at some locations and was dominated by barracuda (Sphyraena spp.), jacks (Carangids), and rainbow runner (Elagatis bipinnulata). Thirty-four percent of fish species observed on these platforms are new records for Gabon and 6% are new to tropical West Africa. Fish assemblages closely associated with platforms had distinct amphi-Atlantic affinities and platforms likely extend the distribution of these species into coastal West Africa. At least one potential invasive species, the snowflake coral (Carijoa riisei), was observed on the platforms. Oil platforms may act as stepping stones, increasing regional biodiversity and production but they may also be vectors for invasive species. Gabon is a world leader in terrestrial conservation with a network of protected areas covering >10% of the country. Oil exploration and biodiversity conservation currently co-exist in terrestrial and freshwater ecosystems in Gabon. Efforts to increase marine protection in Gabon may benefit by including oil platforms in the marine protected area design process.西非加蓬的海洋生物多样性尚未得到充分研究，相关认知大多较为匮乏。本次针对加蓬海域与海上石油平台（oil platforms）相关联的海洋群落开展的调研，是首次对这类设施展开的科学考察，同时也揭示了与之相伴的独特生态系统。在本次平台调研过程中，研究团队记录到多个此前未见于加蓬海域的物种。研究观察到，北部年代更久、规模更大的平台，与南部或近岸较新平台的底栖生物群落（benthic communities）存在显著差异：前者以单体杯形珊瑚（Tubastraea sp.）为优势类群，后者则以钟形巨藤壶（Megabalanus tintinnabulum）为优势类群，但相较于北部平台，南部平台的底栖组合更为多样。过往研究曾记录到加蓬天然岩质基底上存在少量具虫黄藻的石珊瑚（zooxanthellated scleractinian corals），但本次调研中并未在海上石油平台上发现这类珊瑚。部分海域的海上石油平台周边，经估算的鱼类总生物量超过1吨，优势类群包括梭鱼（Sphyraena spp.）、鲹科鱼类（Carangids）以及尖尾平鲹（Elagatis bipinnulata）。本次调研在平台周边记录的鱼类物种中，34%为加蓬海域新记录物种，6%为热带西非海域首次记录的物种。与平台紧密关联的鱼类组合具有显著的跨大西洋亲缘关系（amphi-Atlantic affinities），海上石油平台可能推动这类物种的分布范围向西非近岸海域拓展。研究团队至少在一处平台上观测到一种潜在入侵物种——雪花珊瑚（Carijoa riisei）。海上石油平台既可作为生态踏脚石，提升区域生物多样性与生物生产能力，同时也可能成为入侵物种的传播媒介。加蓬在陆地生物多样性保护领域位居全球前列，其保护区网络覆盖该国超过10%的陆地面积。当前，加蓬的陆地与淡水生态系统中，石油勘探与生物多样性保护实现了并行共存。若将海上石油平台纳入海洋保护区（marine protected area）规划流程，或将助力加蓬的海洋保护工作推进。