Meta-analysis of the effects of organic matter on polychaetes of the east coast of South America.

Polychaetes play a key role in benthic functioning and organic matter recirculation. We performed a meta-analysis to investigate the effects of organic matter on polychaetes, considering its origin, type and measurement along the east coast of South America. We summarize 276 effect sizes, mostly representing the Tropical Southwestern Atlantic and Warm Temperate Southwestern Atlantic provinces. We observed that the effect of organic matter depends on its origin and type. We also reveal that the predominance of tolerant species of Capitellidae, Nereididae and Spionidae explains the great variability in effect sizes and non-significant effects. Organic matter negatively affected assessment of polychaete assemblages, such as aspects of diversity and trophic groups. This result suggests that the impact of organic matter can be more intense for communities than for individual species. We suggest that researchers should investigate more complex ecological scales to understand the overall effect of organic matter on polychaetes. • Polychaetes research on the east coast of South American is biased towards the largest coastal cities and research centers. • The most studied polychaete families tolerant to organic matter influenced the overall null effect of organic matter. • The type and origin of organic matter influences the sensitivity of polychaetes to it. [ABSTRACT FROM AUTHOR]