This feature on oceans was transferred to the Cool Planet website from On the Line. Much of the information here relates to the time when the millennium dawned.
Life began in the oceans. Covering two-thirds of the Earth's surface, in the twenty-first century oceans remain crucial for our survival; for regulating climate, providing us with resources like fish and minerals, and potentially offering us cures for disease.
The oceans are home to half the world's biodiversity, and new species are being found almost daily. In fact, we know more about the moon than we do about the deep ocean. Marine life has adapted to exploit every niche, from the poles to the tropics, from estuaries to the deep ocean.
We take a look at the oceans and seas along the meridian, their importance to man, the diversity of wildlife that inhabit these waters, and some important conservation issues.
After reading these pages try the oceans quiz.
Photo: D Murrell/WWF UK