The dark side of rocks: an underestimated high-quality food resource in river ecosystems

This dataset contains data of fatty acid profiles described in the paper: “Guo et al. (2021) The dark side of rocks: an underestimated high-quality food resource in river ecosystems. Journal of Ecology, https://doi.org/10.1111/1365-2745.13647”. This study was a field investigation conducted along a subalpine river continuum in Austria and aimed to identify the nutritional role of a “hidden” food resource for aquatic consumers; the biofilms growing on the underside of rocks (dark biofilms). Dark and light (i.e., upper surface of rocks) biofilms, and invertebrates were collected, and their fatty acid (FA) composition was analyzed. Main results were: (1) compared with light biofilms, dark biofilms contained greater proportions of bacterial FA, long-chain saturated FA (biomarkers of terrestrial plants), and oleic acid (18:1ω9; a fungal biomarker), but a lower proportion of algal FA, especially omega-3 polyunsaturated FA (ω3 PUFA). (2) The ω3 PUFA composition in dark biofilms was stron...