3
studies, and research directed at determining to what extent blue carbon is sequestered in shallow coastal areas has become popular recently.
We therefore begin this chapter with a discussion of the UNEP report. We then
explain recent trends in studies of blue carbon formation, sequestration, and storage
in shallow coastal areas, and outline the processes associated with carbon sequestration and storage in carbon-storage ecosystems known as carbon sinks. This book
includes extensive reviews of research and practices related to the use of various
shallow coastal ecosystems such as tidal flats, saltmarshes, coral reefs, mangrove
forests, and seagrass meadows. In this chapter, we also discuss biological aspects of
the sequestration and storage of blue carbon by focusing on the key role played by
eelgrass beds. The following sections describe various CO 2 absorption mechanisms
and carbon sequestration and storage processes. This information is essential to
understanding the biological characteristics of eelgrass beds, including their biodiversity and ecosystem services. Finally, we explain why an understanding of biodiversity and the functionality of the whole ecosystem are essential for maintaining
and nurturing the carbon sequestration and storage services provided by shallow
coastal ecosystems.
1.2 Blue Carbon Advocacy
On the one hand, it is common to see headlines such as “Deforestation, acceleration
of global warming”, “Conservation of forests prevents global warming”, or similar
words in the social mass media such as television programs and newspapers. In
contrast, it is uncommon to find headings such as “Decreases of underwater forests
and seaweed beds cause acceleration of global warming”. This difference in public
awareness is a major reason why the UNEP report was published. The report was
intended to enhance public awareness of the differences in climate change countermeasures between the land and ocean.
Many people understand that terrestrial forest ecosystems are under threat owing
to a variety of factors, including deforestation, desertification, forest fires, and the
effects of climate change. These perturbations have been major factors causing the
increase of atmospheric carbon dioxide concentrations. However, marine ecosystems, especially the ocean floor in shallow coastal areas where phytoplankton and
marine macrophytes such as seaweeds and seagrasses grow abundantly, play an
important role in absorbing carbon dioxide. This ecosystem service and the area of
the seafloor where macrophytes are found have decreased greatly in recent years.
Macrophyte-dominated marine ecosystems, like terrestrial forests, are now on the
verge of a crisis. Although marine organisms and shallow coastal waters are sometimes considered important from the standpoint of biodiversity and seafood production, few people associate marine organisms with absorption of carbon dioxide. The
major concerns for the ocean with respect to climate change seem to relate to loss
of biodiversity. Coral reefs, for example, are threatened with decline because of
ocean acidification and increasing water temperatures. Here we consider the
1 Blue Carbon: Characteristics of the Ocean’s Sequestration and Storage Ability…
studies, and research directed at determining to what extent blue carbon is sequestered in shallow coastal areas has become popular recently.
We therefore begin this chapter with a discussion of the UNEP report. We then
explain recent trends in studies of blue carbon formation, sequestration, and storage
in shallow coastal areas, and outline the processes associated with carbon sequestration and storage in carbon-storage ecosystems known as carbon sinks. This book
includes extensive reviews of research and practices related to the use of various
shallow coastal ecosystems such as tidal flats, saltmarshes, coral reefs, mangrove
forests, and seagrass meadows. In this chapter, we also discuss biological aspects of
the sequestration and storage of blue carbon by focusing on the key role played by
eelgrass beds. The following sections describe various CO 2 absorption mechanisms
and carbon sequestration and storage processes. This information is essential to
understanding the biological characteristics of eelgrass beds, including their biodiversity and ecosystem services. Finally, we explain why an understanding of biodiversity and the functionality of the whole ecosystem are essential for maintaining
and nurturing the carbon sequestration and storage services provided by shallow
coastal ecosystems.
1.2 Blue Carbon Advocacy
On the one hand, it is common to see headlines such as “Deforestation, acceleration
of global warming”, “Conservation of forests prevents global warming”, or similar
words in the social mass media such as television programs and newspapers. In
contrast, it is uncommon to find headings such as “Decreases of underwater forests
and seaweed beds cause acceleration of global warming”. This difference in public
awareness is a major reason why the UNEP report was published. The report was
intended to enhance public awareness of the differences in climate change countermeasures between the land and ocean.
Many people understand that terrestrial forest ecosystems are under threat owing
to a variety of factors, including deforestation, desertification, forest fires, and the
effects of climate change. These perturbations have been major factors causing the
increase of atmospheric carbon dioxide concentrations. However, marine ecosystems, especially the ocean floor in shallow coastal areas where phytoplankton and
marine macrophytes such as seaweeds and seagrasses grow abundantly, play an
important role in absorbing carbon dioxide. This ecosystem service and the area of
the seafloor where macrophytes are found have decreased greatly in recent years.
Macrophyte-dominated marine ecosystems, like terrestrial forests, are now on the
verge of a crisis. Although marine organisms and shallow coastal waters are sometimes considered important from the standpoint of biodiversity and seafood production, few people associate marine organisms with absorption of carbon dioxide. The
major concerns for the ocean with respect to climate change seem to relate to loss
of biodiversity. Coral reefs, for example, are threatened with decline because of
ocean acidification and increasing water temperatures. Here we consider the
1 Blue Carbon: Characteristics of the Ocean’s Sequestration and Storage Ability…