Despite the perpetual darkness of the deep sea, contrasting the sunlit epipelagic waters, many deep-sea organisms exhibit rhythmic activities. To discern environmental cues that may serve as entrainment signals for deep-sea organisms, this study investigated the soundscape of the abyssal plain south of Minamitorishima Island. Our analysis revealed clear diel and seasonal patterns, primarily driven by evening fish choruses and marine mammal vocalizations. These evening choruses, discernible above the background noise, likely serve as a circadian time cue for organisms capable of perceiving them within the aphotic depths. In addition, the frequent detection of whistles and echolocation clicks suggests this region functions as a foraging ground for marine mammals. These acoustic cues might guide organisms with auditory capabilities toward habitats rich in sinking food debris and whale falls. By elucidating the ecological processes shaping abyssal soundscape dynamics, these findings open new directions for further exploration in deep-sea chronobiology.

中文翻译：

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声学暮光：长达一年的海底监测揭示了深海声景的物候模式

尽管深海永远黑暗，与阳光照射的上层水域形成鲜明对比，许多深海生物却表现出有节奏的活动。为了辨别可能作为深海生物夹带信号的环境线索，这项研究调查了南鸟岛南部深海平原的声景。我们的分析揭示了明显的昼夜和季节模式，主要是由夜间鱼类合唱和海洋哺乳动物的发声驱动的。这些晚间的合唱在背景噪音中清晰可辨，很可能为能够在无光深度感知它们的生物体提供昼夜节律时间提示。此外，频繁检测到口哨声和回声定位滴答声表明该区域是海洋哺乳动物的觅食地。这些声音线索可能会引导具有听觉能力的生物体前往富含下沉食物残渣和鲸鱼瀑布的栖息地。通过阐明塑造深海声景动力学的生态过程，这些发现为深海时间生物学的进一步探索开辟了新的方向。