This publication is part of the IPIECA-IOGP Good Practice Guide Series which summarizes current views on good practice for a range of oil spill preparedness and response topics. The series aims to help align industry practices and activities, inform stakeholders, and serve as a communication tool to promote awareness and education. The purpose of this document is to provide an overview of how oil spills can impact marine ecological resources and functions, and how quickly those resources and functions can recover. It is based on documented scientific evidence, includes references to specific studies, and is aimed at the general response community consisting of operators, governments, businesses and the public.