The volcanic island, Kueishan Island, harbors two unique shallow-water ecosystems: hydrothermal vents and coral communities. The unique geologic features render the island an ideal place as a spectrum for studying two different ecosystems and mimicking the impacts of climate change on coral reef biota in the future. However, little is known about the meiofauna community there. Hence, we investigated the diversity and composition of free-living marine nematodes over two years by collecting individuals from sediments sampled across a gradient of habitats, including hydrothermal vents, buffering sites, and coral reefs. During the first year, we also monitored abiotic factors, such as sediment and water properties, along with biotic factors, including bacterial diversity assessed through amplicon sequencing, to evaluate their influence on the nematode community. Our findings revealed markedly low nematode abundance and diversity at sulfide-rich vent sites (abundance < 5 ind./L; Shannon index < 1) throughout the study period, contrasting with the highest levels observed at the coral community site (<165.4 ind./L, Shannon index = 1.65). The food supply seemed to be the main factor that drove the difference, as nematode abundance and diversity increased with sedimentary total organic carbon and bacterial diversity. In addition, significant differences in nematode composition were observed between the different sampling sites. Combined with nematode and microbiome data, the buffering site that endured more stress from vent activities was recognized. Our results suggest that the dynamics of nematode communities could be incorporated into projects assessing environmental impacts on coral reef ecosystems.

中文翻译：

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海洋线虫种群的时空变化可以作为海洋生态系统变化的指标


火山岛桂山岛拥有两个独特的浅水生态系统：热液喷口和珊瑚群落。独特的地质特征使该岛成为研究两种不同生态系统和模拟气候变化对未来珊瑚礁生物群影响的理想场所。然而，人们对那里的 meiofauna 群落知之甚少。因此，我们通过从栖息地梯度（包括热液喷口、缓冲地点和珊瑚礁）的沉积物中收集个体，在两年内调查了自由生活的海洋线虫的多样性和组成。在第一年，我们还监测了非生物因素，例如沉积物和水的性质，以及生物因素，包括通过扩增子测序评估的细菌多样性，以评估它们对线虫群落的影响。我们的研究结果显示，在富含硫化物的喷口部位（丰度 < 5 ind./L;香农指数 < 1），与在珊瑚群落地点观察到的最高水平形成鲜明对比（<165.4 ind./L，香农指数 = 1.65）。食物供应似乎是导致这种差异的主要因素，因为线虫的丰度和多样性随着沉积物总有机碳和细菌多样性的增加而增加。此外，在不同采样点之间观察到线虫组成的显着差异。结合线虫和微生物组数据，确定了承受更多通风活动压力的缓冲位点。我们的结果表明，线虫群落的动态可以纳入评估环境对珊瑚礁生态系统影响的项目。