Community patch‐dynamics governs direct and indirect nutrient recycling by aggregated animals across spatial scales

Animals can have pervasive effects on ecosystems as they modify their biogeochemical and physical environments. In particular, when animals occur in high densities these effects can result in dramatic changes in the physical environment and biogeochemical hotspots or hot moments. While most research to date has focused on the direct role of animals in biogeochemical cycles, few have examined how animals indirectly influence biogeochemical cycles across scales.

Freshwater mussels occur as spatially heterogeneous, dense and species-rich aggregations in many river ecosystems worldwide. Here we examined how mussel communities (1) directly influence the flux of particulate and dissolved nutrients and (2) indirectly effect the flux of N2 production, via denitrification, across a gradient of mussel biomass and differences in community composition at the patch- (0.25 m2) and stream reach-scales (60-80 m).

We combined measurements of ammonia (N) and soluble reactive phosphorous (P) excreti...