Universal classification schemes have been proposed for the vertical zonation of sessile benthos on intertidal rocky shores; however, generalized patterns among deep-sea meiofauna of different regions remain rare. We conducted a preliminary, family-level study of deep-sea harpacticoid diversity and community composition off Tosa Bay, Shikoku island, Japan, along a transect on a landward continental slope of the Nankai Trough. We then compared these data to those of other subduction zones along the Japanese island arc, including the Kuril, Japan, and Ryukyu trenches. Common bathymetric trends in harpacticoid composition were observed among these subduction zones from upper bathyal to abyssal depths (400–5800 m). Ectinosomatidae was the most abundant family within this depth interval; however, its frequency decreased with increasing depth, whereas the abundance of Pseudotachidiidae was highest at abyssal depths. Harpacticoid composition differed significantly between landward slopes of the Ryukyu Trench and those of the Japan and Kuril trenches. However, harpacticoid composition on the landward slope of the Nankai Trough, between the Ryukyu and Japan trenches, was similar to that around the neighboring subduction zones. These findings imply that patterns of deep-sea harpacticoid community composition are similar along the continental slope of the Japanese island arc, and that the Izu–Ogasawara arc, which subdivides the subduction zones, has not functioned as a physical barrier to harpacticoid expansion between zones.

中文翻译：

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首次了解日本岛弧俯冲带向陆斜坡深海细海藻多样性和成分的测深模式

潮间带岩岸无柄底栖动物的垂直分区已提出通用分类方案；然而，不同地区深海小型动物的普遍模式仍然很少见。我们对日本四国岛土佐湾沿南海海槽向陆陆坡的一个横断面的深海 harpacticoid 多样性和群落组成进行了初步的家庭级研究。然后我们将这些数据与日本岛弧沿线的其他俯冲带的数据进行了比较，包括千岛、日本和琉球海沟。在从上半深到深海深度（400-5800 m）的这些俯冲带中，观察到了 harpacticoid 成分的常见测深趋势。Ectinosomatidae 是该深度区间内数量最多的科；然而，它的频率随着深度的增加而降低，而 Pseudotachidiidae 的丰度在深海深处最高。琉球海沟的陆坡与日本和千岛海沟的陆坡之间的 Harpacticoid 成分存在显着差异。然而，位于琉球海沟和日本海沟之间的南海海槽向陆斜坡上的harpacticoid成分与邻近俯冲带周围的成分相似。这些发现意味着深海 harpacticoid 群落组成的模式沿着日本岛弧的大陆坡是相似的，并且细分俯冲带的 Izu-Ogasawara 弧没有作为区域之间 harpacticoid 扩张的物理屏障. 琉球海沟的陆坡与日本和千岛海沟的陆坡之间的 Harpacticoid 成分存在显着差异。然而，位于琉球海沟和日本海沟之间的南海海槽向陆斜坡上的harpacticoid成分与邻近俯冲带周围的成分相似。这些发现意味着深海 harpacticoid 群落组成的模式沿着日本岛弧的大陆坡是相似的，并且细分俯冲带的 Izu-Ogasawara 弧没有作为区域之间 harpacticoid 扩张的物理屏障. 琉球海沟的陆坡与日本和千岛海沟的陆坡之间的 Harpacticoid 成分存在显着差异。然而，位于琉球海沟和日本海沟之间的南海海槽向陆斜坡上的harpacticoid成分与邻近俯冲带周围的成分相似。这些发现意味着深海 harpacticoid 群落组成的模式沿着日本岛弧的大陆坡是相似的，并且细分俯冲带的 Izu-Ogasawara 弧没有作为区域之间 harpacticoid 扩张的物理屏障.