Data from: Macrofouling communities and the degradation of plastic bags in the sea: an in situ experiment

The increasing amount of plastic littered into the sea may provide a new
substratum for benthic organisms. These marine fouling communities on
plastic have not received much scientific attention. We present, to our
knowledge, the first comprehensive analysis of their macroscopic community
composition, their primary production and the polymer degradation
comparing conventional polyethylene (PE) and a biodegradable starch-based
plastic blend in coastal benthic and pelagic habitats in the Mediterranean
Sea. The biomass of the fouling layer increased significantly over time
and all samples became heavy enough to sink to the seafloor. The fouling
communities, consisting of 21 families, were distinct between habitats,
but not between polymer types. Positive primary production was measured in
the pelagic, but not in the benthic habitat, suggesting that large
accumulations of floating plastic could pose a source of oxygen for local
ecosystems, as well as a carbon sink. Contrary to PE, the biodegradable
plastic showed a significant loss of tensile strength and disintegrated
over time in both habitats. These results indicate that in the marine
environment, biodegradable polymers may disintegrate at higher rates than
conventional polymers. This should be considered for the development of
new materials, environmental risk assessment and waste management
strategies.