Oceans take up a majority of the planet's surface and are an important home for many species. However, climate change and human activities are endangering the health of ocean environments. This title examines some of the biggest threats oceans and marine species are facing today, including rising sea levels, overfishing, and plastic pollution. It also looks at steps being taken to help protect the world's oceans, ways in which activists have contributed to conservation efforts, and how everyday people can get involved. Features include a glossary, references, websites, source notes, and an index. Aligned to Common Core Standards and correlated to state standards. Essential Library is an imprint of Abdo Publishing, a division of ABDO.