Marine birds and plastic pollution

The intrinsic properties and widespread presence of plastic particles in the marine environment have profound effects on birds inhabiting the world's oceans. Industrial and user-plastics composed of polystyrene, polypropylene, polyethylene, styrofoam, and polyvinyl chloride are the most prevalent forms of plastic marine pollution. Their dispersal and accumulation, in average densities of 1000 to 4000 pieces km-2, are controlled by surface currents, wind patterns, and different geographic inputs. Seabirds in the order ProceUariiformes are most vulnerable to the effects of plastic ingeshon due to their smaller gizzard and their inability to regurgitate ingested plastics. Planktivores have a higher incidence of ingested plastics than do piscivores as the former are more likely to confuse plastic pellets with copepods, euphausiids, and cephalopods. Hence, &et may be a major factor determining the quantity of plastic ingested. Physiological effects related to the ingestion of plastics include obstruction of the gastrointestines and of subsequent passage of food into the intestines, blockage of gastric enzyme secretion, diminished feeding stimulus, lowered steroid hormone levels, delayed ovulation and reproductive failure. As plastic manufacture and use increases and subsequent disposal at sea becomes more extensive, the impact of dscarded plastic on birds inhabiting the marine environment may also be expected to increase. The beauty and geiiius of a work of ari nldy be reconceived, though its first material expression be destroyed; a vanished harmony may yet again inspire the composer; but when the last individual of a race of living beings breathes no more, another heaven and another earth mustpass before such a one can be again.