Mangrove photo: Ken Funakoshi via flickr.
More and more research has been coming out recently on how much carbon is stored in different ecosystems. The latest is from an IUCN report (via Mongabay) which shows that coastal habitats store up to 50 times more carbon in their soils by area than tropical forests, and ten more than temperate forests too:It all comes down to how well mangroves, salt marshes and areas of sea grass can transfer carbon into the soil, as compared to how well this is done in tropical and temperate forests.
Coastal salt marsh in Connecticut, photo: Wikipedia
With tropical forests, in general, the majority of carbon storage takes place in above-ground vegetation; in temperate forests it's more evenly split and in the case of boreal forests the balance tilts towards more stored in soil below-ground.
Dr. Emily Pidgeon of Conservation International says,
The simple implication of this is that the longterm sequestration of carbon by one square kilometer of mangrove area is equivalent to that occurring in fifty square kilometers of tropical forest. Hence, while relatively small in area, coastal habitats are extremely valuable for their longterm carbon sequestration capacity.
Forest AND Coastal Habitat Preservation Important
All of which isn't to say that protection of forests as carbon sinks (let alone all the other great reason to protect forests...) isn't important -- both tropical and temperate forest conservation is vitally important -- rather, as Dr. Pidgeon says, "The immense carbon sequestration capacity of these coastal habitats has been almost completely ignored and may also be a vital component in global efforts to mitigate climate change."
More: The Management of Natural Coastal Carbon Sinks [PDF]
Mangroves, Coastal Ecosystems
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