UMR 7266 Littoral, Environment et Societies (CNRS - University of La Rochelle), Institute du littoral et de l'environnement, 2 rue Olympe de Gouges, 17000, La Rochelle, France; Alfred Wegener Institute Helmholtz Centre for Polar- and Marine Research, Wattenmeerstation Sylt, Hafenstraße 43, 25992, List, Sylt, Germany.
Alfred Wegener Institut Helmholtz Centre for Polar- and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany.
Mar Environ Res. 2019 Aug;149:50-66. doi: 10.1016/j.marenvres.2019.05.014. Epub 2019 May 22.
Meiofauna can play an important role in the carbon fluxes of soft-bottom coastal habitats. Investigation of their feeding behavior and trophic position remains challenging due to their small size. In this study, we determine and compare the food sources used by nematodes and benthic copepods by using stable isotope compositions, fatty acid profiles and compound specific isotope analyses of fatty acids in the mudflats, seagrass beds and a sandflat of the Marennes-Oléron Bay, France, and the Sylt-Rømø Bight, Germany. Suspended particulate organic matter was much more C-depleted than other food sources and meiofauna, highlighting its poor role in the different studied habitats. The very low proportions of vascular plant fatty acid markers in meiofauna demonstrated that these consumers did not rely on this food source, either fresh or detrital, even in seagrass beds. The combined use of stable isotopes and fatty acids emphasized microphytobenthos and benthic bacteria as the major food sources of nematodes and benthic copepods. Compound specific analyses of a bacteria marker confirmed that bacteria mostly used microphytobenthos as a substrate.
小型底栖动物在软底沿海生境的碳通量中起着重要作用。由于它们体积小，研究它们的摄食行为和营养位置仍然具有挑战性。在这项研究中，我们通过稳定同位素组成、脂肪酸图谱和脂肪酸的特定化合物同位素分析，确定并比较了法国马恩-奥勒隆湾的泥滩、海草床和沙滩以及德国叙尔特-罗默比希特的线虫和底栖桡足类使用的食物来源。悬浮颗粒有机物质比其他食物来源和小型底栖动物更富含 C，这突出表明它在不同研究生境中的作用较差。小型底栖动物中很少有维管植物脂肪酸标志物，这表明这些消费者要么不依赖这种食物来源，要么不依赖新鲜的或碎屑的食物来源，即使在海草床也是如此。稳定同位素和脂肪酸的综合使用强调了微小型底栖植物和底栖细菌是线虫和底栖桡足类的主要食物来源。细菌标记物的特定化合物分析证实，细菌主要以微小型底栖植物为基质。
