First Global Study: Seagrasses Can Store as much Carbon as Forests

5/19/2012

Researchers find that the Global Carbon Pool in Seagrass Beds is as much as 19.9 billion metric tons

Arlington, VA — A new study published this week in the journal Nature Geoscience,  shows that seagrasses are a vital part of the solution to climate change and that per unit area, seagrass meadows can store up to twice as much carbon as the world’s temperate and tropical forests.
 
 The paper, “Seagrass Ecosystems as a Globally Significant Carbon Stock,” is the first global analysis of carbon stored in seagrasses and demonstrates that coastal seagrass beds store up to 83,000 metric tons of carbon per square kilometer, mostly in the soils below them. For comparison, a typical terrestrial forest stores around 30,000 metric tons per square kilometer, most of which is in the form of wood.
 
This research also estimates that, although seagrass meadows occupy less than 0.2 percent of the world’s oceans, they are responsible for more than 10 percent of all carbon buried annually in the ocean.
 
“Seagrasses only take up a small percentage of global coastal area, but this assessment shows that they are a dynamic ecosystem for carbon transformation,” said Dr. James Fourqurean, the lead author of the paper, a professor of biology at Florida International University and scientist with the Blue Carbon Initiative. “Seagrasses have the unique ability to continue to store carbon in their roots and soil in coastal seas. We found instances where particular seagrass beds have been storing carbon for thousands of years.”

According to the study, seagrass meadows store ninety percent of their carbon in the soil and continue to build on this for centuries. In the Mediterranean, which is the geographic region with the greatest concentration of carbon found from the study, seagrass meadows were found to store carbon in deposits many meters deep.
 
Seagrasses are among the world’s most threatened ecosystems. Roughly 29 percent of all historic seagrass meadows have been destroyed, mainly due to dredging and degradation of water quality.   Furthermore, at least 1.5% of seagrass meadows are lost every year. This study estimates that emissions from destruction of seagrass meadows can potentially emit up to 25 percent as much carbon as from terrestrial deforestation.
“One remarkable thing about seagrass meadows is that, if restored, they can effectively and rapidly sequester carbon and reestablish lost carbon sinks," said coauthor Karen McGlathery, Professor, University of Virginia.
 
Seagrasses have long been recognized for their many ecosystem benefits: they filter sediment from the oceans; they protect coastlines against floods and storms; and they serve as vital habitats for fisheries production.
 
"The results of this global analysis emphasizes the importance of seagrass conservation and restoration," according to Dr. Bill Dennison, Vice President for Science Applications at the University of Maryland Center for Environmental Science. He added "In addition to providing habitats and nurseries for fish and shellfish and stabilizing sediments to reduce erosion, we now know that seagrass meadows have a crucial role in regulating global carbon."
 
This research was led by scientist Dr. James Fourqurean of Florida International University, in partnership with others from, the Spanish High Council for Scientific Investigation, the Oceans Institute at the University of Western Australia, Bangor University in the UK, the University of Southern Denmark, the Hellenic Center for Marine Research in Greece, Aarhus University in Denmark and the University of Virginia. The study emphasizes that conserving and restoring seagrass meadows may reduce greenhouse gas emissions and increase carbon stores, while also delivering key ecosystem services to coastal communities.
 
“Our vital seagrass ecosystems have always been a conservation priority, given their myriad benefits of ecosystem services to local communities” said Dr. Emily Pidgeon, Senior Director of Strategic Marine Initiatives at Conservation International and co-chair of the Blue Carbon Initiative. “Now we must also recognize the vital importance of Coastal ‘blue’ carbon ecosystems, such as seagrass meadows, for their importance to global climate health.”
 
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Note to editors:
 
Blue Carbon Initiative Scientific Working Group
A number of authors on the paper are expert members of the Blue Carbon Initiative’s Scientific Working Group, the first integrated program with a comprehensive and coordinated global agenda focused on mitigating climate change through the conservation and restoration of coastal marine ecosystems. The Initiative is a collaborative effort between Conservation International (CI), the International Union for Conservation of Nature (IUCN), and the Intergovernmental Oceanic Commission (IOC) of UNESCO.
 
About Conservation International (CI)
Building upon a strong foundation of science, partnership and field demonstration, CI empowers societies to responsibly and sustainably care for nature, our global biodiversity, for the long term well-being of people. Founded in 1987 and marking its 25th anniversary in 2012, CI has headquarters in the Washington DC area, and 900 employees working in nearly 30 countries on four continents, plus 1,000+ partners around the world.  For more information, please visit at www.conservation.org , or on Facebook or Twitter.
 
About Florida International University
FIU is recognized as a Carnegie engaged university. Its colleges and schools offer more than 180 bachelor’s, master’s and doctoral programs in fields such as marine biology, engineering, international relations, architecture, law and medicine. As one of South Florida’s anchor institutions, FIU is Worlds Ahead in its local and global engagement, finding solutions to the most challenging problems of our time. FIU emphasizes research as a major component of its mission. It has 160,000 alumni and enrolls 48,000 students in two campuses and three centers including FIU Downtown on Brickell and the Miami Beach Urban Studios. For more information about FIU, visit www.fiu.edu.