Data from: How to estimate community energy flux? A comparison of approaches reveals that size-abundance tradeoffs alter the scaling of community energy flux

Abstract: Size and metabolism are highly correlated, so that community energy flux might be predicted from size distributions alone. However, the accuracy of predictions based on interspecific energy-size relationships relative to approaches not based on size distributions is unknown. We compare six approaches to predict energy flux in phytoplankton communities across succession: assuming a constant energy use among species (per cell or unit biomass), using energy-size interspecific scaling relationships and species-specific rates (both with or without accounting for density effects). Except the per cell approach, all others explained some variation in energy flux but their accuracy varied considerably. Surprisingly, the best approach overall was based on mean biomass-specific rates, followed by the most complex (species-specific rates with density). We show that biomass-specific rates alone predict community energy flux because the allometric scaling of energy use with size measured for species in isolation does not reflect the isometric scaling of these species in communities. We also find energy equivalence throughout succession, even when communities are not at carrying capacity. Finally, we discuss that species assembly can alter energy-size relationships, and that metabolic suppression in response to density might drive the allometry of community energy flux as biomass accumulates.

1. Data summary: Empirical rates of community metabolism and net production, and community rates estimated from six different approaches (see Fig. 1 in manuscript). Measurements of metabolism and photosynthesis for each phytoplankton species measured individually are also reported (data from Malerba et al. 2017 Ecology).

2. Community estimates from each approach: calculations of community rates (metabolism and net production) for each approach (Fig. 1 in manuscript).

3. Community oxygen rates: estimates of variability among the 5 subsamples taken to characterise the metabolism and photosynthesis rate of each replicate community (under 6 light intensities and over 10 weeks).