Abstract Isopods are a highly diversified group of deep-sea fauna, with a wide variety of shapes which must reflect a similar great variety of adaptations to the deep environments. The deep Mediterranean, however, has a low diversity of isopods related to its oligotrophy, the thermal stability of deep-water masses (~12.8 °C below 150–200 m) and rather homogeneous geomorphology. The main factor defining isopod habitats in the Balearic Basin is insularity vs mainland influence. Desmosomatidae and Ischnomesidae, examples of epibenthic species (with lack of paddle-shaped legs and non/low-natatory capacity) are mainly linked to mainland areas with higher % organic matter (OM) and labile C, indicating food availability. By contrast, suprabenthic species like Munnopsidae (with some paddle-shaped, natatory, legs) are more dominant in insular areas. Compared with the Atlantic, the degree of impoverishment in diversity (number of species, S) of deep-Mediterranean asellotes is higher among epibenthos (with a lot of families/genera absent in the deep Mediterranean) than for suprabenthic species, with potential natatory capacity (natatory legs). This suggests that the high diversity of deep sea asellotes may depend on the trophic niches (sediment richness and diversity of habitats) available. In the 20 yrs period (1991–2011) of our (non-continuous) sampling series we identified some climatic influence (higher ENSO index) on the high densities reported in 1991–1992 samples, related to species taken at submarine canyons in mainland areas. Higher food availability (by advection) in canyons during 1991 and 1992 related with an increase of rainfall regime may enhance recruitment (e.g. in March 1992 inside canyons) and abundance/diversity of asellotes, especially for epibenthic species (Desmosomatidae).

中文翻译：

---

地中海西部的深海等足类动物：分布和栖息地

摘要 等足类动物是一个高度多样化的深海动物群，具有各种各样的形状，必须反映对深海环境的相似的多种适应性。然而，深地中海的等足类动物多样性较低，这与其寡营养、深水团的热稳定性（150-200 m 以下约 12.8 °C）和相当均质的地貌有关。定义巴利阿里盆地等足类动物栖息地的主要因素是岛国与大陆的影响。Desmosomatidae 和 Ischnomesidae，底栖物种的例子（缺乏桨状腿和非/低自然能力）主要与有机物百分比 (OM) 和不稳定 C 较高的大陆地区有关，表明食物供应。相比之下，像 Munnopsidae（有一些桨状的、游泳的腿）这样的底栖动物在岛屿地区更占优势。与大西洋相比，深地中海星形藻的多样性（种数，S）的贫乏程度在底栖生物（地中海深部缺少许多科/属）中高于底栖生物，具有潜在的游泳能力（自然腿）。这表明深海星形体的高度多样性可能取决于可用的营养生态位（沉积物丰富度和栖息地的多样性）。在我们（非连续）采样系列的 20 年期间（1991-2011 年），我们确定了一些气候影响（更高的 ENSO 指数）对 1991-1992 年样本中报告的高密度，与在大陆地区海底峡谷采集的物种有关. 1991 年和 1992 年与降雨量增加有关的峡谷中较高的食物供应（通过平流）可能会增加补充（例如