CN_mass_data            Data: Nutrient concentrations, stable isotope
                        ratios, and biomass from destructive mesocosm
                        harvests
allometry               Data: Stem masses and heights for plants
                        collected from Colt State Park, Rhode Island,
                        USA, during summer 2016
ap                      Convert per mil isotope values to atom percent
bCM                     Parameterize Box-Cox model for mass-height
                        allometry (based on Lu et al. 2016)
dea                     Data: Denitrification enzyme activity and in
                        vitro N2O production rates
nappCalc2               Calculate net aboveground primary production
nmolHr_mgDay            Convert N2O units from nanomoles of N2O per
                        hour to milligrams of N per day
se                      Calculates standard error
stemHeights             Data: Stem heights for each mesocosm and each
                        measurement date
