264
DOC. However, dissolved substances after decomposition include both DIC and
DOC; therefore, in the model, DIC was considered to contain DOC as well.
Suspended organic matter that settles on the sea bottom is buried by means of
sedimentation. However, if strong flow occurs due to a tidal current or a meteorological disturbance, the organic matter is resuspended into the water column (resuspension). The amount of resuspended matter can be estimated from the bottom
shear stress calculated by the ocean flow model. Bottom shear stress is a force
applied to the seabed driven by bottom currents, and if this stress is large, the amount
of resuspended matter is increased. The suspended particles are decomposed while
repeating the resuspension and settling, and those particles that are not decomposed
eventually accumulate on the seabed and are buried. As a result, eelgrass-derived
organic carbon is stored in the sediment. In addition, some particles are transported,
settle, and are stored in the deep sea.
9.5.1.3 Outflow of Drifting Leaves and Particulate Organic Matter
The outflow points and amounts of drifting leaves and eelgrass-derived suspended
organic matter are described here. Based on the distribution of eelgrass beds estimated from satellite image analysis (Hori et al. 2012), the outflow points were configured in the dense and sparse eelgrass beds in the computational grids of the
model. Each eelgrass bed area was calculated by multiplying the resolution of the
Labile (42)
Semi-labile
(52)
Refractory (6)
leaves
Semi-labile
(52)
Refractory (6)
DIC
DIC
POC
POC
k 1 = 0.020exp(0.0693T )
k 2 = 0.007exp(0.0693T )
Semi-labile
(52)
Refractory (6)
POC
Rs: respiration, Ph: photosynthesis,
Of: outflowing, Fo: falling off,
St: settling, Fr: fragmentation,
Ss: suspension, Dc: decomposition,
Ac: accumulation, Fl: floating,
Rss: resuspension
Decomposition of POC
discharged from eelgrass bed
POC
DIC
decomposition
rate (k 2 )
decomposition rate (day -1 )
(T, water temp.)
decomposition
rate (k 1 )
fragmentation
rate (k 2 )
decomposition
rate (k 2 )
Decomposition of leaves discharged from eelgrass bed
Fig. 9.11 Transport and decomposition processes of leaves and suspended organic matter that
flow out of eelgrass beds. The numbers in parentheses are the percentages of total organic carbon
K. Abo et al.
DOC. However, dissolved substances after decomposition include both DIC and
DOC; therefore, in the model, DIC was considered to contain DOC as well.
Suspended organic matter that settles on the sea bottom is buried by means of
sedimentation. However, if strong flow occurs due to a tidal current or a meteorological disturbance, the organic matter is resuspended into the water column (resuspension). The amount of resuspended matter can be estimated from the bottom
shear stress calculated by the ocean flow model. Bottom shear stress is a force
applied to the seabed driven by bottom currents, and if this stress is large, the amount
of resuspended matter is increased. The suspended particles are decomposed while
repeating the resuspension and settling, and those particles that are not decomposed
eventually accumulate on the seabed and are buried. As a result, eelgrass-derived
organic carbon is stored in the sediment. In addition, some particles are transported,
settle, and are stored in the deep sea.
9.5.1.3 Outflow of Drifting Leaves and Particulate Organic Matter
The outflow points and amounts of drifting leaves and eelgrass-derived suspended
organic matter are described here. Based on the distribution of eelgrass beds estimated from satellite image analysis (Hori et al. 2012), the outflow points were configured in the dense and sparse eelgrass beds in the computational grids of the
model. Each eelgrass bed area was calculated by multiplying the resolution of the
Labile (42)
Semi-labile
(52)
Refractory (6)
leaves
Semi-labile
(52)
Refractory (6)
DIC
DIC
POC
POC
k 1 = 0.020exp(0.0693T )
k 2 = 0.007exp(0.0693T )
Semi-labile
(52)
Refractory (6)
POC
Rs: respiration, Ph: photosynthesis,
Of: outflowing, Fo: falling off,
St: settling, Fr: fragmentation,
Ss: suspension, Dc: decomposition,
Ac: accumulation, Fl: floating,
Rss: resuspension
Decomposition of POC
discharged from eelgrass bed
POC
DIC
decomposition
rate (k 2 )
decomposition rate (day -1 )
(T, water temp.)
decomposition
rate (k 1 )
fragmentation
rate (k 2 )
decomposition
rate (k 2 )
Decomposition of leaves discharged from eelgrass bed
Fig. 9.11 Transport and decomposition processes of leaves and suspended organic matter that
flow out of eelgrass beds. The numbers in parentheses are the percentages of total organic carbon
K. Abo et al.