Animal-sediment relationships: Evaluating the ‘Pearson–Rosenberg paradigm’ in Mediterranean coastal lagoons

We investigated the applicability of the Pearson–Rosenberg (P–R) conceptual model describing a generalized pattern of response of benthic communities in relation to organic enrichment to Mediterranean Sea coastal lagoons. Consistent with P–R model predictions, benthic diversity and abundance showed two different peaks at low (>2.5–5 mg g−1) and high (>25–30 mg g−1) total organic carbon (TOC) ranges, respectively. We identified TOC thresholds indicating that risks of reduced benthic diversity should be relatively low at TOC values < about 10 mg g−1, high at TOC values > about 28 mg g−1, and intermediate at values in-between. Predictive ability within these ranges was high based on results of re-sampling simulation. While not a direct measure of causality, it is anticipated that these TOC thresholds should serve as a general screening-level indicator for evaluating the likelihood of reduced sediment quality and associated bioeffects in such eutrophic systems of the Mediterranean Sea.