Data from: Chlorpyrifos interacts with other agricultural stressors to alter stream communities in laboratory microcosms

Chlorpyrifos is one of the most widely used agricultural insecticides in
the world, but to date there is limited empirical information about its
potential to interact with other common agricultural stressors. We
conducted a 15-day, community-level microcosm experiment evaluating
individual and combined effects of chlorpyrifos, nutrient enrichment, and
sedimentation on stream invertebrate communities (abundance, biomass,
richness, size structure, composition) and ecosystem processes (primary
productivity and leaf decomposition). We found that sedimentation was the
most detrimental stressor, with significant negative impacts on most
invertebrate community and ecosystem function variables. Even though
chlorpyrifos did not cause significant invertebrate mortality in the
microcosms, it still altered ecosystem function by lowering leaf
decomposition rates, probably through sublethal inhibition of invertebrate
shredders. Furthermore, we observed a significant reversal interaction
between chlorpyrifos and sediment for small-sized invertebrates collected
in gravel (abundance in sediment x insecticide microcosms was 2.4 times
lower than predicted by additivity), as well as an antagonistic
interaction with nutrients on invertebrate richness in the same
microhabitat (richness in nutrient x insecticide microcosms was 1.6 times
higher than predicted by additivity). Our results suggest that
chlorpyrifos has the potential to alter freshwater ecosystem function and
interact non-additively with other common agricultural stressors. These
findings are in keeping with a growing body of research highlighting that
multiple stressor interactions and ecosystem processes should be
considered when evaluating the impacts of organic toxicants on freshwater
ecosystems.