Major threats that cold seep ecosystems and their communities face today are seafloor litter, chemical contaminants and climate change. Seafloor litter alters the habitat, by providing hard substrate where none was available before or by overlying the sediment, inhibiting gas exchange, and interfering with organisms on the bottom of the sea. Studies of marine litter in the Mediterranean include surveys of seabed debris on the continental shelf, slope, and bathyal plain. In most studies, plastic items accounted for much of the debris, sometimes as much as 90% or more of the total, owing to their ubiquitous use and poor degradability.