Seagrass can help mitigate climate change

Sydney, May 23 (IANS) Seagrasses can hold as much carbon as the world's temperate and tropical forests and play an important role in mitigating in climate change, says a first global analysis conducted by researchers.

Results gathered from 3,640 observations of 946 distinct seagrass meadows across the globe show that coastal seagrass beds store up to 83,000 metric tonnes of carbon per square kilometre, mostly in the soils below them. Comparatively, a typical land forest stores around 30,000 metric tonnes per sq.km.

"These results show that seagrass meadows are key sites for carbon storage and probably are far more important as carbon dioxide sinks deeper than we realised," Gary Kendrick, professor at the University of Western Australia, was quoted as saying in the journal Nature Geoscience.

Kendrick and colleague Carlos Duarte co-authored the study with James Fourqurean, biology professor at Florida International University, US.

The research also estimates that, although seagrass meadows occupy less than 0.2 per cent of the world's oceans, they are responsible for more than 10 per cent of all 'blue carbon' stores buried annually in the ocean and rival carbon stores in the extensive peat deposits of mangroves, according to a university statement.

Data sets as deep as one metre were concentrated in Florida Bay, US, the Spanish coast of the western Mediterranean, and Shark Bay, western Australia.

The greatest concentration of carbon found was in the Mediterranean, where seagrass meadows stored 90 percent of their carbon in the soil and continue to build on this indefinitely.

Seagrasses are among the world's most threatened eco-systems. These unusual marine flowering plants are called seagrasses because in many species the leaves are long and narrow, and they often grow in large "meadows" which look like grassland.

Around 29 percent of all historic seagrass meadows have been destroyed, mainly due to dredging and degradation of water quality and a further 1.5 per cent of seagrass meadows are lost each year.