Seagrass beds, which play an important role in coastal marine ecosystems and absorb large quantities of carbon dioxide, are increasingly being destroyed or degraded by development and pollution, according
to a new study. Reporting in the journal Proceedings of the National Academy of Sciences, American and Australian researchers estimated that 29 percent of the world’s seagrass beds have disappeared since 1879, with most of the losses occurring since 1980. Only 68,000 square miles of seagrass beds remain, making them “among the most threatened ecosystems on earth,” along with coral reefs and mangrove swamps, the study said. Seagrass meadows provide a major spawning area and juvenile nursery for fish, with some estimates saying that 70 percent of all marine life is in some way dependent on seagrass beds. The loss of seagrasses — the only flowering plants that can live entirely in water — “reveals a major global environmental crisis in coastal ecosystems,” the study said.