Chemical cycles in the biosphere: Footage from around the world and informative computer graphics show how chemicals cycle within the biosphere Emphasized are the oxygen-carbon dioxide cycle, the water cycle, acid rain and how toxic chemicals affect the biosphere. Ecosystems on Earth: What is the state of Earth's ecosystems as the 21st century begins? A primer on ecosystem problems and opportunities with the stress on new efforts to save endangered species, new efforts to avert global warming and new efforts to preserve and restore health to all ecosystems, including agricultural and urban ones. Food chains in the biosphere: Learn how producers, consumers, decomposers and the abiotic elements are connected in ecosystems and how ecosystems make up a biosphere.

May include guides. Title from disc surface. "Three videos on one DVD." Date on guides, c1992-c2001.

Chemical cycles in the biosphere [21 min.]. -- Ecosytems on Earth [21 min.]. -- Food chains int he biosphere [19 min.].