INTRODUCTION
Of all the Green carbon captured annually in the world, that is the carbon captured by
photosynthetic activity, over half (55%) is captured by marine living organisms (Falkow
ski et al., 2004; Arrigo, 2005; González, et al., 2008; Bowler, 2009; Simon et al., 2009).
This oceanic carbon cycle is dominated by micro, nano, and picoplankton, including
bacteria and archaea (Burkill, 2002). Even though plant biomass in the oceans is only
a fraction of that on land, just 0.05%, it cycles almost the same amount of carbon each
year (Bouillon et al., 2008; Houghton, 2007); therefore representing extremely efficient
carbon sinks. However, while increasing efforts are being made to slow degradation on
land, such as through protection of rainforests as a means to mitigate climate change, the
role of marine ecosystems has to date been largely ignored.
Knowledge of the role of natural ecosystems in capturing CO
2
(González et al., 2008), and remove over 30% of the carbon
is an increasingly important component in developing strate- released to the atmosphere.
gies to mitigate climate change. Losses and degradation of
natural ecosystems comprise at least 20–30% of our total emis- Resilient aquatic ecosystems not only play a crucial role in bind-
sions (UNEP, 2008a; 2009). While overall emissions from the ing carbon, they are also important to economic development,
burning of fossil fuels needs to be severely reduced, mitigating food security, social wellbeing and provide important buffers
climate change can also be achieved by protecting and restoring against pollution, and extreme weather events. Coastal zones
natural ecosystems (Trumper et al., 2009). Even from a nar- are of particular importance, with obvious relations and impor-
row perspective of emission reductions alone, they can play a tance to fisheries, aquaculture, livelihoods and settlements (Kay
significant role. As steep reduction of fossil fuel emissions may and Alder, 2005) – over 60% of the world’s population is settled
compromise the development potential of some countries, it is in the coastal zone (UNEP, 2006, 2008b). For many coastal
critical that options are identified that can help mitigate climate developing countries, the coastal zone is not only crucial for
change with neutral or even positive impacts on development. the wellbeing of their populations, it could also, as documented
It is therefore absolutely critical to identify those natural ecosys- in this report, provide a highly valuable global resource for cli-
tems that contribute most to binding our increasing emissions mate change mitigation if supported adequately.
of carbon or CO
2
and enhance this natural capacity (Trumper et
al., 2009). Some of these are in the oceans. This report explores the potential for mitigating the impacts
of climate change by improved management and protection of
Some 93% of the earth’s carbon dioxide – 40Tt CO
2
– is stored marine ecosystems and especially the vegetated coastal habitat,
in the oceans. In addition, oceans cycle about 90 Gt of CO
2
yr
–1
or blue carbon sinks.
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