Human beings are increasingly making their homes on the coasts of continents, but this demographic shift is taking a toll on a sensitive coastal ecosystem that is often overlooked: seagrass meadows. A new analysis of seagrass abundance around the world found that 27 percent of these meadows have disappeared since 1879, and the rate of loss is accelerating. The study’s authors write: “Seagrass loss rates are comparable to those reported for mangroves, coral reefs and tropical rainforests, and place seagrass meadows among the most threatened ecosystems on earth….. Our report of mounting seagrass losses reveals a major global environmental crisis in coastal ecosystems, for which seagrasses are sentinels of change” [Nature News].
Endangered species expert Susanne Livingstone notes that despite these losses seagrass rarely makes it into the public consciousness. “It’s probably because they’re not as sexy [as corals], they’re not as attractive,” she says. “They’re just as ecologically important if not more so” [Nature News]. Seagrass meadows provide grazing for a variety of marine animals, including the green turtle and the manatee-like dugong. The coastal areas also serve as nurseries for fish; both coral reefs and commercial fisheries would feel the impact if seagrass meadows vanish.
In the study, which will be published in the Proceedings of the National Academy of Sciences, researchers say that nutrients in sewage and run-off from agriculture and industry are the major cause of seagrass death…. These nutrients trigger the growth of algae, plants and animals that grow above or on seagrass, and stop it from getting the sunlight it needs [Australian Broadcasting Corporation].
Seagrasses, which evolved from terrestrial plants, are the only flowering plants that can live entirely in water. They are most closely related to lilies and are very different to seaweeds, which are algae…. Seagrass beds are believed to rival rice paddies in their photosynthetic productivity or the ability to extract greenhouse gas CO2 and convert it into oxygen and stored carbon matter [Reuters]. If seagrass meadows continue to shrink in shallow coastal waters around the world, it will accelerate the pace of global warming, researchers say.
Related Content:
80beats: Feds Say Global Warming’s Effects Can Be Seen in Our Own Backyards
80beats: Climate Change & Disease Have “Flattened” Caribbean Coral Reefs
80beats: No More Speculation: Scientists Prove Ocean Acidification is Already Underway
Image: flickr / jayhem
June 30th, 2009 at 5:50 pm
Unless the number of people goes down or we figure out how to exponentially decrease our impact on the environment per person, isn’t this kind of thing going to inevitably get worse? People need to live somewhere, and we are going to inhabit places even if there are ecosystems crucial to the homeostasis of the planet residing there. The planet is going to change. We might have a better chance of figuring out how to breathe our own CO2 than we have of stopping its accumulation.
July 1st, 2009 at 12:27 pm
The human population is eventually going to decrease, whether because we stop breeding like rabbits or because millions of us starve- something is going to happen. I’d advocate birth control if I had to choose. Or, maybe we need a high population to increase our chances of surviving a cataclysm. Who knows?
July 1st, 2009 at 3:22 pm
Non-sexy science? Blasphemy!
July 4th, 2009 at 8:26 pm
Mother nature always eleminates disruptive species over time. We have become disruptive…. if we don’t figure out a way to stop the imbalances we create than she will find a way to get rid of us…. and don’t worry.. the seagrass will come back pretty quickly after we are gone.