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Metabolism is an integrative metric of ecosystem energetics, synthesizing the relative contributions of multiple inputs, processes, and interactions. Ecological stoichiometry is a framework based on elemental ratios for understanding how organisms interact with their environment. Together, they have the potential to yield novel insight about how ecosystems use elements and energy. In this study, we sought to quantify the link between the stoichiometry of ecosystem metabolism, specifically the C:N:P ratios of integrated autotrophic assimilation, and the stoichiometric ratios observed in the dominant autotrophs. Using high frequency in situ nutrient sensors we estimated the assimilatory fluxes of C, N, and P in multiple spring-fed rivers of varying autotrophic species composition. We measured autotroph cover in each spring river, collected composite vegetation samples, and evaluated tissue stoichiometry; as expected, we observed large differences in C:N and N:P between algal and vascular plant taxa. We observed a strong association between measured tissue stoichiometry and elemental ratios at the ecosystem scale, suggesting that aggregated assimilatory fluxes may be useful for partitioning primary production and linking organismal nutrient content to the stoichiometry of ecosystem metabolism. |