Scour marks from the heavy doors of the trawl were observed in the seafloor and persisted for at least a year.
Trawl doors can create scour marks (or troughs) in the sediment as they are towed along the bottom of the seafloor.
Scour marks were immediately visible on the substrate during visual surveys conducted 2 weeks after high-intensity trawling--an observation consistent with those of the condition of the seafloor after low-intensity trawling.
The persistence of scour marks from the doors of the small-footrope bottom trawl was the primary impact observed in our study.
Despite the minimal reduction in microtopographic complexity observed in the trawled plots, we did find, on a larger scale, alteration of the seafloor in the form of scour marks from trawl doors that were visible immediately after both low- and high-intensity trawling and that persisted for up to a year after low-intensity trawling.
Nearby were scour marks in the surface blasted by thrusters, which kicked up a swirl of dust.
Scientists were giddy about the scour marks because they exposed bedrock below — information that should help them better understand the landing site.