266
continued to moderately decrease until the end of the calculation period as they
were resuspended and decomposed or flowed out of the area.
Figure 9.14 shows distributions of the leaves, suspended particles, and organic
carbon accumulated in the sediment in September 2011 when the leave biomass was
maximum, in February 2012 when the deposition amount was maximum, and at the
end of the calculation period in December 2012. On 15 September, the leaves were
distributed in most of the area, but particularly large numbers existed in the central
part of the Seto Inland Sea. The leaves were assumed to diffuse from the eelgrass
beds to the entire Seto Inland Sea. On 30 December, there were no leaves in the area
because they settled on the sea bottom and fragmented. At the end of the calculation, the carbon in the sediment was distributed around Aki-nada in the central part
of the sea area and in island coves where many eelgrass beds are distributed. In
addition, sediment carbon was also distributed in the southern part of Hiuchi-nada
and the central part of Aki-nada, where few eelgrass beds existed. These areas have
low flow velocity, making resuspension difficult, and they are adjacent to many
eelgrass beds. On the other hand, in the strait and other places with fast flow, the
carbon content in the sediment was small. The eelgrass gene distribution in the
sediment obtained from the field survey (Fisheries Agency of Japan) was qualitatively in good agreement with the carbon distribution in the sediment at the end of
the calculation, which validates the results of the modal calculation.
Figure 9.15 shows the mass balance of the eelgrass-derived organic carbon in the
Seto Inland Sea at the end of the model calculation. Of the eelgrass-derived organic
carbon that flowed out of eelgrass beds, 97.4% was drifting leaves and 2.6% was
suspended particles. After 1 year, 67% of the carbon was decomposed into
DIC + DOC, and most of it flowed out of the Seto Inland Sea, with only 6.7%
remaining in the sea. As for the organic carbon that flowed out of the Seto Inland
Sea, 17.1% outflowed as suspended particles and 6.3% as drifting leaves. The
Fig. 9.13 Calculation result of the amount of eelgrass-derived carbon that flowed out of eelgrass
beds (time series of each carbon component in the Seto Inland Sea). POC particulate organic carbon, DIC dissolved organic carbon
K. Abo et al.
continued to moderately decrease until the end of the calculation period as they
were resuspended and decomposed or flowed out of the area.
Figure 9.14 shows distributions of the leaves, suspended particles, and organic
carbon accumulated in the sediment in September 2011 when the leave biomass was
maximum, in February 2012 when the deposition amount was maximum, and at the
end of the calculation period in December 2012. On 15 September, the leaves were
distributed in most of the area, but particularly large numbers existed in the central
part of the Seto Inland Sea. The leaves were assumed to diffuse from the eelgrass
beds to the entire Seto Inland Sea. On 30 December, there were no leaves in the area
because they settled on the sea bottom and fragmented. At the end of the calculation, the carbon in the sediment was distributed around Aki-nada in the central part
of the sea area and in island coves where many eelgrass beds are distributed. In
addition, sediment carbon was also distributed in the southern part of Hiuchi-nada
and the central part of Aki-nada, where few eelgrass beds existed. These areas have
low flow velocity, making resuspension difficult, and they are adjacent to many
eelgrass beds. On the other hand, in the strait and other places with fast flow, the
carbon content in the sediment was small. The eelgrass gene distribution in the
sediment obtained from the field survey (Fisheries Agency of Japan) was qualitatively in good agreement with the carbon distribution in the sediment at the end of
the calculation, which validates the results of the modal calculation.
Figure 9.15 shows the mass balance of the eelgrass-derived organic carbon in the
Seto Inland Sea at the end of the model calculation. Of the eelgrass-derived organic
carbon that flowed out of eelgrass beds, 97.4% was drifting leaves and 2.6% was
suspended particles. After 1 year, 67% of the carbon was decomposed into
DIC + DOC, and most of it flowed out of the Seto Inland Sea, with only 6.7%
remaining in the sea. As for the organic carbon that flowed out of the Seto Inland
Sea, 17.1% outflowed as suspended particles and 6.3% as drifting leaves. The
Fig. 9.13 Calculation result of the amount of eelgrass-derived carbon that flowed out of eelgrass
beds (time series of each carbon component in the Seto Inland Sea). POC particulate organic carbon, DIC dissolved organic carbon
K. Abo et al.