Poriferans Rift Apart: Molecular sponge biodiversity in Central and French Polynesia and comparison with adjacent marine provinces of the Central Indo-Pacific. French Polynesia Sponge Biodiversity

The distribution of marine sponges in the tropical Southwest Pacific Ocean is largely unexplored despite the vital ecological role of sponges in coral reefs and their valuable metabolites for drug design. Several collection campaigns to the French Polynesian archipelagos (Society, Marquesas, Tuamotu, Gambier, and Austral) were conducted to assess the bio- and chemodiversity of the island groups. These campaigns resulted in the acquisition of over 200 sponge specimens, for which we generated molecular Operational Taxonomic Units (MOTUs). Based on these MOTUs, we assessed, in the so-far largest analysis of its kind for this area, the sponge composition and faunistic overlaps of the marine province Southeast Polynesia with Marquesas and Central Polynesia. We also compared the sponge fauna of these Eastern Indo-Pacific provinces with marine provinces of the adjacent Central Indo-Pacific realm. Our findings corroborate that sponge faunal similarity within marine realms is higher than among realms, and follows marine barriers to gene flow as established for other taxa. We detected high levels of provincial endemism for marine sponges, consistent with findings from other Indo-Pacific regions. At the level of province, geographical distance and ocean surface currents influence faunal similarity, and constitute the primary factors for the connectivity of sponge faunas between the disjunct and remote island groups in the tropical Southwest Pacific Ocean.

尽管海绵在珊瑚礁生态系统中发挥着至关重要的生态作用，且其所含的活性代谢产物可用于药物研发，但热带西南太平洋海域的海洋海绵分布情况仍未得到充分探明。针对法属波利尼西亚群岛下辖的社会群岛（Society）、马克萨斯群岛（Marquesas）、土阿莫土群岛（Tuamotu）、甘比尔群岛（Gambier）与南方群岛（Austral），研究团队开展了多次标本采集工作，以评估该岛群的生物多样性与化学多样性。本次采集共获得200余份海绵标本，并为这些标本生成了分子操作分类单元（molecular Operational Taxonomic Units，MOTUs）。基于这些MOTUs，本研究开展了该区域迄今规模最大的同类分析，评估了东南波利尼西亚海洋生物地理区与马克萨斯群岛、中波利尼西亚的海绵群落组成及区系重叠情况。此外，本研究还将这些东印度-太平洋海洋生物地理区的海绵群落，与邻近的中印度-太平洋域的海洋生物地理区进行了对比分析。研究结果证实，同一生物地理域内的海绵区系相似性高于跨域之间的相似性，且该相似性模式符合其他类群所确立的基因流海洋屏障规律。本研究检测到海洋海绵具有较高的生物地理区特有性水平，这与印度-太平洋其他区域的研究结果一致。在生物地理区尺度上，地理距离与海洋表层洋流影响着区系相似性，是热带西南太平洋区域离散且偏远的岛群之间海绵群落连通性的核心影响因素。