背景:评估关键食物网组成部分的历史动态对于了解气候变化如何影响北极海洋生态系统的结构至关重要。迄今为止,大多数回顾性稳定同位素研究都使用脊椎动物顶级捕食者和滤食无脊椎动物作为代理来评估北极潜在的生态系统变化。然而,由于漫长的生活史和特定的生态,使用这些分类单元时,生态系统的变化并不总是可以检测到的。此外,目前还没有对北极生物群的其他各种生态和分类类群进行回顾性稳定同位素研究.为了测试气候驱动的海洋生态系统变化是否反映在短命中生动物的生态学中,分析了来自低纬度北极和邻近水域的两种丰富的鱿鱼(Gonatusfabricii和Todarodessagultatus)中几丁质硬体结构中稳定同位素特征的个体发育变化,在1844年至2023年之间收集。
结果:我们发现饮食和栖息地-使用普遍性(=机会主义选择而不是专业化)的时间增加,来自低纬度北极水域的G.fabricii的营养位置和生态位宽度。营养生态的这些变化与北极生态系统的大西洋化相吻合,其中包括增加食物网的泛化和更高的初级生产,以及气候变化导致北大西洋北方物种的涌入。自1990年代末/2000年代初以来,大西洋化尤其明显。我们在G.fabricii的营养生态学中发现的时间模式在以前的北极回顾性同位素生态学研究中基本上没有报道。因此,如今在高纬度北大西洋出现的T.sagittatus的饮食比十九世纪更加通才。
结论:我们的结果表明,具有较短生命周期的大量机会性中捕食者(如鱿鱼)是在海洋生态系统中进行回顾性生态学研究的良好候选者。并确定由气候变化驱动的生态系统变化。北极食物网的增强泛化反映在鱿鱼的饮食泛化和生态位宽度增加,而北方食鱼的丰度增加反映在鱿鱼的营养位置增加。这些发现支持鱿鱼的机会主义和适应性,这使他们成为北极生态系统短期变化的潜在赢家。
BACKGROUND: Assessing the historical dynamics of key food web components is crucial to understand how climate change impacts the structure of Arctic marine ecosystems. Most retrospective stable isotopic studies to date assessed potential ecosystem shifts in the Arctic using vertebrate top predators and filter-feeding invertebrates as proxies. However, due to long life histories and specific ecologies, ecosystem shifts are not always detectable when using these taxa. Moreover, there are currently no retrospective stable isotopic studies on various other ecological and taxonomic groups of Arctic biota. To test whether climate-driven shifts in marine ecosystems are reflected in the ecology of short-living mesopredators, ontogenetic changes in stable isotope signatures in chitinous hard body structures were analysed in two abundant squids (Gonatus fabricii and Todarodes sagittatus) from the low latitude Arctic and adjacent waters, collected between 1844 and 2023.
RESULTS: We detected a temporal increase in diet and habitat-use generalism (= opportunistic choice rather than specialization), trophic position and niche width in G. fabricii from the low latitude Arctic waters. These shifts in trophic ecology matched with the Atlantification of the Arctic ecosystems, which includes increased generalization of food webs and higher primary production, and the influx of boreal species from the North Atlantic as a result of climate change. The Atlantification is especially marked since the late 1990s/early 2000s. The temporal patterns we found in G. fabricii\'s trophic ecology were largely unreported in previous Arctic retrospective isotopic ecology studies. Accordingly, T. sagittatus that occur nowadays in the high latitude North Atlantic have a more generalist diet than in the XIXth century.
CONCLUSIONS: Our results suggest that abundant opportunistic mesopredators with short life cycles (such as squids) are good candidates for retrospective ecology studies in the marine ecosystems, and to identify ecosystem shifts driven by climate change. Enhanced generalization of Arctic food webs is reflected in increased diet generalism and niche width in squids, while increased abundance of boreal piscivorous fishes is reflected in squids\' increased trophic position. These findings support opportunism and adaptability in squids, which renders them as potential winners of short-term shifts in Arctic ecosystems.