The values of natural abundance of stable isotopes were measured in 22 species of macrophytes (18 macroalgae and 4 vascular plants) collected from the intertidal domain in NW Spain (NE Atlantic). This dataset contains the values of natural abundance of stable carbon and nitrogen isotopes in bulk samples and of nitrogen isotopes in amino acids.
Samples were oven dried (50°C, 24h) upon arrival to the laboratory (<24h). Samples were analyzed in an elemental analyzer (bulk samples, Viana and Bode, 2013, 2015) or a gas chromatograph (derivatized amino acids, Bode et al., 2021) coupled to isotope-ratio mass spectrometers.Empty cells = not determined.