Coastal ecosystems are the unique habitats formed by plants and other organisms that can thrive at the borders between ocean and land, where they must live in saltwater and changing tides. Like forests, many of these coastal ecosystems are full of plants that help regulate the Earth’s temperature. As the plants in these ecosystems grow, they pull carbon out of the air and store it in their tissue, roots, and the soil beneath them. This keeps carbon out of our atmosphere, where the greenhouse gas carbon dioxide would otherwise trap heat and warm the planet.