This ecosystem is sometimes land and sometimes sea that supports the estuary and acts as a buffer. It is one of most productive ecosystems in the world. Many plants and animals are shown. The Big Sweep clean-up program is also profiled. There are 10 videos in the Return to the Sea video series: Oceans Under Glass/ Swimming With Whales/ A Day On the Reef/ Secrets of the Shark/ The Art of Underwater Photography/ The Ocean at Night and The Sea of Cortez/ The Graveyards of the Atlantic and Pacific Oceans/ People Who Make a Difference/ The Reef at the End of the Road and The Last Days of the Manatee/ Life in a Salt Marsh