Marine benthic communities and anthropogenic activities in Sept-Îles (Canada): a peaceful coexistence?

With the development of coastal human activities comes the growing need to develop methods to describe their cumulative impacts on marine benthic communities at local geographic scales. Local assessments facilitate dialogue between multiple users of the ecosystem (industries, individuals) and allow to better understand variation among benthic communities in a given region. In this project, we aim to develop indicators of cumulative impacts to assess the environmental health of benthic ecosystems within industrialized regions in the Gulf of St. Lawrence at a small spatial scale (0.01 km²).

We selected coastal regions around Sept-Îles, where numerous human activities are present at different intensities (such as international shipping, fisheries or domestic and industrial wastes). Subtidal ecosystems were sampled in 2016-2017 to characterize macro-endobenthic diversity and abiotic parameters of the sediment. We calculated impact scores for each human activity based on the distance from the source and the magnitude of its impact. We thus identified hotspots of cumulative impact and changes in the biotic and abiotic compartments along impact gradients. These results will be used for the development of indicators of cumulative stress and to understand resilience and stability of bay-scale benthic communities.