Mean (‰) and standard deviation (±SD) of carbon and nitrogen isotope values for each carbon source, and ANOVA results for the test of differences among basins.

<p>PR = Paraná; PA = Pantanal; AR = Araguaia; AM = Amazon; n = number of samples for each source in each basin. Shared superscript lowercase letters indicate lack of significant differences for the Tukey post-hoc test.</p>