Fig. 1: Literature end members of nitrogen isotopes in phenylalanine, glutamic acid and alanine.
From: Mixotrophy emerges as an optimal strategy in mature waters of the Amazon River plume
A δ15NPhe (phenylalanine) vs δ15NGlu (glutamic acid + glutamine) and B δ15NPhe (phenylalanine) vs δ15NAla (alanine) of the literature end members16,18,24,65,66. Symbols represent the organisms: cultured fungi (square), cultured bacteria (diamond), cultured Archaea (triangle), cultured protozooplankton (crossed circle), and cultured microalgae (circle). Colors represent the nitrogen source: dissolved inorganic nitrogen (green, DIN), dissolved organic nitrogen (purple, DON), nitrogen from phagocytosis (pink, N from preys). Trophoclines (dashed and dotted gray lines) with a slope of 1.0 and y-intercepts of 3.4‰, 7.2‰, and 11.0‰ for δ15NGlu and of 3.2‰, 6.0‰, and 8.9‰ for δ15NAla, respectively, represent different trophic positions (TPs = 1.0, 1.5, 2.0) according to Chikaraishi et al.24. Data are provided in Supplementary Data 1 for a total of n = 46 individual samples collected from literature.
