Tidal coasts are characterized by natural disturbances, forming a broad variety of habitats, which provide different niches and varying food resources for benthic foraminifera. Foraminifera occupy different trophic levels and fill key trophic positions in benthic food webs, but detailed studies on their nutrition spectrum in inter- to supratidal environments are lacking. Further, it is unknown to what extent foraminifera can switch between different feeding modes depending on resource availability in different Wadden Sea habitats. In order to shed light on these questions, we investigated potential food resources in sediments as well as the food spectrum of two dominant benthic foraminifera, Trochammina inflata and Ammonia tepida, in four characteristic habitats of the Wadden Sea: salt marsh, mixed flat, oyster reef and mud flat, using fatty acid (FA) analysis. The sediments of the four habitats provide a broad range of food sources including green algae, brown algae, diatoms and bacteria for benthic foraminifera. The FA profile of T. inflata from the salt marsh and mixed flat was dominated by green algae and bacteria, whereas the brown algae biomarker was only found in specimens from the salt marsh. In comparison, FA profiles of A. tepida suggested dominant algae feeding (green algae and diatoms), whereas brown algae and bacterial FAs were only found in specimens from the oyster reef. The results suggest that foraminifera mainly feed at low trophic levels with selective food intake closely depending on their habitat. The diverse nutritional strategies may allow efficient exploitation of resources in dynamic tidal habitats. Presumably, foraminifera serve as an important link between lower and higher trophic levels and thus fill key trophic positions in the benthic food web of the Wadden Sea.

中文翻译：

---

瓦登海底栖有孔虫的食物谱和栖息地特定饮食——脂肪酸生物标志物方法

潮汐海岸的特点是自然干扰，形成了各种各样的栖息地，为底栖有孔虫提供了不同的生态位和不同的食物资源。有孔虫占据不同的营养级别并填补底栖食物网中的关键营养位置，但缺乏对它们在潮间带上环境中的营养谱的详细研究。此外，不知道有孔虫可以在多大程度上根据不同瓦登海栖息地的资源可用性在不同的饲养模式之间切换。为了阐明这些问题，我们调查了沉积物中潜在的食物资源以及两种主要底栖有孔虫（Trochammina inflata 和 Ammonia tepida）在瓦登海的四个特征栖息地：盐沼、混合平原、牡蛎的食物谱礁石和泥滩，使用脂肪酸 (FA) 分析。四个栖息地的沉积物提供了广泛的食物来源，包括绿藻、褐藻、硅藻和底栖有孔虫的细菌。来自盐沼和混合平原的 T. inflata 的 FA 剖面以绿藻和细菌为主，而褐藻生物标志物仅在盐沼的标本中发现。相比之下，A. tepida 的 FA 谱表明主要以藻类为食（绿藻和硅藻），而褐藻和细菌 FA 仅在牡蛎礁的标本中发现。结果表明，有孔虫主要以低营养水平为食，其选择性食物摄入量密切取决于其栖息地。多样化的营养策略可以有效地开发动态潮汐栖息地的资源。想必，