The newly proposed threshold for enzymatic stoichiometry: A reliable solution?

Abstract

The enzymatic stoichiometry approach assumes that microbial enzyme production reflects metabolic and stoichiometric demands; therefore, soil microbial nutrient limitations can be inferred from the activity levels of soil enzymes catalyzing compounds containing limiting nutrients. A vector model analysis further advanced this approach by proposing a 1:1:1 threshold for carbon (C), nitrogen (N), and phosphorus (P) limitations. However, this threshold has been criticized for lacking a solid theoretical foundation. To address this limitation, a novel method was recently introduced to establish a new threshold based on theoretical concepts. This new threshold was evidenced by the fact that the empirical threshold determined as the inflection point of the regression lines representing the relationship between vector angle and vector length corresponded with the theoretical values. Here, I demonstrated that this pattern can be generated using entirely random data, undermining the reliability of the conclusions. Furthermore, the theoretical foundation for determining the new threshold contains certain limitations, highlighting the need for an alternative threshold.