Contrasting sediment properties at trawled and untrawled areas.
From left to right, vertical profiles of: dry bulk density (A); total 210Pb concentration (B) and organic carbon content (C), in sediment cores collected at the flanks of La Fonera Canyon, grouped according to their position in fishing grounds (red) or control (untrawled) areas (blue). The profile with the highest densities corresponds to core NF-5 from the distal part of the north canyon flank. The shadowed area in the central panel represents supported (in equilibrium with 226Ra) 210Pb. Concentration values in excess of that threshold indicate net accumulation of recently (within the order of a century) deposited sediments, while 210Pb concentrations within the threshold indicate sediments older than 100–150 years. Horizontal error bars in 210Pb data are 1-sigma. For the sake of clarity, an isolated value of organic carbon of 1.9% at 4 cm for core SF-1 has been omitted.