Ten inconvenient questions about plastics in the sea

Abstract

This paper aims to investigate some of the hottest issues that concern the increasing presence of plastics in the sea. In an attempt to identify the main knowledge gaps and to suggest future research, we discuss priority topics on marine plastic pollution through ten thought-provoking questions on the current knowledge of multiple consequences of plastics on the marine ecosystem. Our investigation found that the majority of knowledge gaps include not only intrinsic aspects of plastics (e.g. quantification, typology, fate), but also biological, ecological and legislative implications (e.g. ingestion rate by wildlife, biomagnification across food webs, spread of alien species, consequences for human nutrition, mitigation measures). The current scenario shows that science is still far from assessing the real magnitude of the impact that plastics have on the sea. In particular, the transfer of plastics across marine trophic levels emerged as one of the most critical knowledge gaps. Current regulations seem not sufficient to tackle the massive release of plastics into the sea. Within this complex picture, a positive note is the ever-increasing public awareness. The release of plastics into the sea is certainly a serious environmental issue that can be effectively addressed only through the combined efforts of the three main stakeholders: ordinary citizens through more eco-friendly behaviours, scientists by filling knowledge gaps, and policymakers by passing conservation laws relying on prevention and scientific evidence.