The stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope values of soft tissues of micronekton (crustaceans, squid, mesopelagic fish) and zooplankton were measured from organisms collected on the RV Antea at two seamounts located in the south-western Indian Ocean: La Pérouse (summit depth ~60 m) and “MAD-Ridge” (thus named in this study; summit depth ~240 m). Surface particulate organic matter (POM-Surf) showed higher δ¹³C at the more productive MAD-Ridge than at the oligotrophic La Pérouse seamount. Particulate organic matter and zooplankton were depleted in ¹⁵N at La Pérouse pinnacle compared with MAD-Ridge. Gelatinous organisms and crustaceans occupied the lowest and intermediate trophic levels (TL ~2 and 3 respectively) at both seamounts. Mesopelagic fish and smaller-sized squid sampled at both seamounts occupied TL ~3 to 4, whereas the large nektonic squid, Ommastrephes bartramii, collected at MAD-Ridge only, exhibited a TL of ~5. The δ¹⁵N values of common open-water mesopelagic taxa were strongly influenced by specimen size and feeding habits at both seamounts, with an increase in δ¹⁵N values with increasing size. Carnivorous fish species sampled exclusively over the seamounts’ flanks and summits exhibited TL values of ~4, irrespective of their wide size ranges. The work could not demonstrate any differences in δ¹³C values of mesopelagic fish between the seamounts and the surrounding oceanic areas. The study segregated clusters of mesopelagic organisms according to their δ¹³C and δ¹⁵N values, with variations in stable isotope values reflecting a complex range of processes possibly linked to productivity as well as biological and ecological traits of the species (size and feeding mode).

稳定的碳（δ ¹³ C）和氮（δ ¹⁵ N）micronekton的软组织的同位素值（甲壳类，墨鱼，中层鱼）和浮游动物，从收集在RV生物体测量ANTEA在位于两个海山西南部印度洋：拉佩鲁斯（LaPérouse）（最高深度约60 m）和“ MAD-Ridge”（因此在本研究中被命名；最高深度约240 m）。表面颗粒有机物（POM-冲浪）显示出较高的δ ¹³在更高效MAD-岭下比在贫营养拉彼鲁兹海山。^15人体内的颗粒有机物和浮游动物消耗de尽LaPérouse顶峰的N与MAD-Ridge的相比。在两个海山上，胶质生物和甲壳类的营养级最低和中等（分别为TL〜2和3）。在两个海山采样的中古生鱼和小鱿鱼的TL约为3至4，而仅在MAD-Ridge收集的大型中性鱿鱼Ommastrephes bartramii的TL约为5。的δ ^15个N条共通开放水域中层类群值强烈试样尺寸和在两个海山食性的影响，与增加δ ¹⁵N值随大小增加。仅从海山的侧面和山顶取样的食肉鱼类显示的TL值为〜4，无论其大小范围如何。这项工作不能证明δ任何差异^1个3海山和周围海洋区域之间的中层鱼类的C值。该研究根据它们的δ偏析中层生物体的簇¹³ C和δ ^15个N个值，与在稳定的同位素的值反映的可能链接到生产率以及生物和生态性状的品种（大小和进给模式的处理的复杂的范围的变化）。