teamseagrass: Seagrasses store carbon better than trees

Jun 15, 2012

Seagrasses store carbon better than trees

Seagrasses do a much better job of storing carbon than trees! Unlike forests that hold carbon for about 60 years then release it again, seagrass ecosystems have been capturing and storing carbon since the last ice age.

A dugong feeding trail on Chek Jawa leaves a 'smiley face'
with some of the many seagrass creatures found here.

In a study of 946 seagrass meadows around the world, an international team of researchers estimated that seagrass captures 27.4 million tonnes of carbon each year.

That means that up to 19.9 billion tonnes of carbon are currently stored within seagrass plants and the top metre of soil beneath them – more than twice the Earth's global emissions from fossil fuels in 2010.

Sadly, in the past century, 29% of seagrass has been destroyed globally", mostly by water pollution, dredging for new developments, and climate change. With seagrass meadows disappearing at an annual rate of about 1.5 per cent, 299 million tonnes of carbon are also released back into the environment each year. If the seagrass dies, all of that could be released into the environment.

Another study found that 55% of global atmospheric carbon captured by living organisms happens in the ocean. Between 50-71% of this is captured by the ocean's vegetated "blue carbon" habitats, which cover less than 0.5 percent of the seabed.

Carbon stored and taken out of the atmosphere by coastal ecosystems such as mangroves, seagrass and salt marsh is called blue carbon. Blue carbon is important because it allows investment in protection of coastal ecosystems. These ecosystems are important for more than just carbon sequestration and storage - they provide food through fish and protect coastal populations from storms and tsunamis.

An important aspect of blue carbon is that most of it is found in the soil beneath the ecosystems, not in the biomass above ground. Carbon can be stored for millennia due to sea level fluctuation, as opposed to terrestrial forests that reach the carbon saturation point earlier.

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