Thursday, May 24, 2012

Why are seagrasses important?

Seagrasses provide many important services such as filtering sediments from the oceans, protecting coastlines against floods and storms, providing habitats for fish and other marine life, etc.

Their most important function is carbon storage. This means that seagrasses are one of our vital allies in our fight against global warming and climate change.

In the recent study (by Florida scientists) that was published in the journal Nature Geoscience researchers have emphasized the role of seagrass meadows in sinking carbon by claiming that seagrasses can store twice as much carbon as the world's forests.

In numbers this means that coastal seagrass beds sink up to 83,000 metric tons of carbon per square kilometer, while on the other hand a typical terrestrial forest stores about 30,000 metric tons per square kilometer.

Seagrass meadows occupy less than 0.2 percent of the world's oceans, but regardless of this very small percentage they still account for more than 10 percent of all carbon buried annually in the sea, mostly in the roots and soils beneath them. The scientists were even able to discover the areas where seagrass beds have been storing carbon for thousands of years.

The bad side of this story is the fact that seagrass meadows are disappearing fast, and are among the world's most threatened ecosystems. The scientists have said that close to 30% of all historic seagrass meadows have already been destroyed over the years with the main factors behind this loss being dredging and degradation of water quality. They also say that more than 1.5 percent of Earth's seagrass meadows are lost every year.

The further destruction of seagrass meadows will result in more carbon emissions. The scientists say that the destruction of seagrass meadows can potentially emit up to 25 percent more carbon that deforestation.

The good news in this story is the fact that seagrasses can be restored, and once restored can rapidly start storing carbon and even reestablish lost carbon sinks.

Conserving and restoring seagrass meadows should therefore become a global concern because seagrasses not only provide important services to many ecosystems but also reduce greenhouse gas emissions, preventing even stronger climate change impact.

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