When the levee breaks: Effects of flood on offshore water contamination and benthic community in the Mediterranean (Ionian Sea)

In the last few years extreme weather events, including changes to storm frequency and intensity, have increased across all continents. In this note we assessed, for the first time in the Mediterranean Sea, the impact of a violent storm and consequent flood on offshore water contamination and benthic community along the Calabrian coast (Ionian Sea). Three sites (at 500, 1000, and 2000 m off the coast) were sampled along three parallel transects in 2013, 2014 (before), and 2015 (after the flood). After the flood, metals (especially Al, CrVI, Ni, Cu, Zn) in the water column increased in concentration. The flood affected the structure of the benthic community, causing a decrease of diversity, the dominance of few opportunistic species, and the decrease of M-AMBI values. •The impact of a flood on offshore benthic community was assessed for the first time in the Mediterranean.•Metals (Al, CrVI, Ni, Cu, Zn) in the water column increased in concentration after the flood.•The flood affected the structure of the benthic community, causing a decrease of diversity.•Few opportunistic species dominated the community after the flood.