Water chemistry, and isotopic ratios and fatty acids and alcohols in Calanus finmarchicus CV, norther Mid-Atlantic Ridge

Fatty acid and alcohol profiles and stable nitrogen and carbon isotope values, d15N and d13C, of Calanus finmarchicus CV were studied in June 2004 to estimate their trophic status along the northern Mid-Atlantic Ridge i.e. the Reykjanes Ridge (RR), extending from Iceland in the north to the productive region of the Sub-Polar Front (SPF) in the south. Two main groups of stations were defined in the study area based on fatty acid (FA) and fatty alcohol compositions, the stations in the RR area constituted one group and the stations in the frontal area constituted another. The sum of relative amounts of the dietary FAs was significantly higher in the RR area than in the frontal area. Conversely, the long-chained FAs, 20:1 and 22:1, were found in significantly lower relative amounts in the RR area than in the frontal area, thus indicating later ascent of the animals in the frontal area. Further support of this is provided by the fatty alcohols ratio 20:1/22:1 which differed significantly between the two areas. The d15N values were significantly higher in the frontal area compared to the RR area indicating higher trophic position and/or different pelagic-POM baseline in these areas.2004年6月，本研究针对大西洋中脊北部沿线——即北起冰岛、南至亚极锋（Sub-Polar Front, SPF）高生产力区域的雷克雅内斯海岭（Reykjanes Ridge, RR）——开展研究，分析了该区域内CV期飞马哲水蚤（Calanus finmarchicus）的脂肪酸与脂肪醇组成，以及稳定氮、碳同位素值（d15N与d13C），旨在评估其营养状态。 研究区域基于脂肪酸（Fatty Acid, FA）和脂肪醇的组分特征被划分为两大站位群：雷克雅内斯海岭区域的站位构成一组，锋面区域的站位则为另一组。 雷克雅内斯海岭区域的膳食来源脂肪酸相对总量显著高于锋面区域。 与之相反，长链脂肪酸20:1与22:1在雷克雅内斯海岭区域的相对占比显著低于锋面区域，这表明锋面区域的该类浮游动物的营养级上升时序更晚。 脂肪醇比值20:1/22:1在两个研究区域间存在显著差异，进一步佐证了上述结论。 锋面区域的d15N值显著高于雷克雅内斯海岭区域，提示该区域浮游动物拥有更高的营养层级，或两个区域的浮游颗粒有机物（pelagic-POM）基线存在差异。