Invertebrate Communities and Ecosystem Functions in Response to Ecosystem Engineering and Multiple Stressors in a Marine Mussel Bed

This dataset compiles data on invertebrate communities and ecosystem functions (respiration, ammonium production, sediment accumulation) collected during an experiment in the summer of 2021 at a mussel bed in Métis-sur-Mer. This factorial experiment tested the impact of the density of an engineer species (blue mussel - Mytilus edulis), the ecosystem’s development time, and multiple stressors (nutrients, thermal stress) on the invertebrate communities colonizing blue mussel patches and on the resulting ecosystem functions.

The experiment began in late May 2021, when cages were anchored in the mid-intertidal zone of the mussel bed near the Métis-sur-Mer lighthouse. A total of 120 cages were installed, filled with blue mussels, and subjected to 24 different treatments (each with 5 replicates). The controlled factors were mussel density, the month of harvest for each cage, thermal stress, and the addition of nutrients. Each month - July, August, and September - one-third of the cages were harvested and incubated in outdoor tanks, in incubation chambers of approximately 30 L, to measure oxygen levels (Fibox and optodes) and ammonium levels (water samples and fluorometry). The community of associated benthic macroinvertebrates and coarse sediments present in each cage were collected using a 500-µm sieve. The fieldwork was conducted by two master’s students (McGill University and Laval University).