Environmental Engineering Reference
In-Depth Information
3. This increasing acidity is believed to have a
direct adverse impact on molluscan species.
The general norm of lowering shell biomass
with the lowering of aquatic pH holds good
for western and eastern Indian Sundarbans,
where the salinity values range from 18.61 to
20.25 psu (in the western sector) and 12.60 to
13.78 psu (in the eastern sector). However, in
the hypersaline central sector, where the
salinity value ranges from 18.03 to 20.34 psu,
the dissolution of calcareous shell of
biosequestration. Biosequestration is the gen-
eral term used to describe activities where
plants such as trees are used to
or
absorb carbon from the atmosphere. Plants
achieve this via photosynthesis, which con-
verts carbon dioxide into oxygen and plant
material (Drury et al.
2004
). The magnitude of
sequestered carbon can vary considerably
depending on the site, species and other
external conditions. The CSIRO states that the
'
'
sequester
'
Saccos-
net amount of atmospheric carbon that is
sequestered by a biosequestration project is the
balance between changes in above-ground
vegetation, roots, the litter layer, and the soil
trea cucullata
is not evident (
Vide
row 6 in
Table
6.2
).
4. The aquatic pH plays no role on stored carbon
in oyster
'
04.pdf
). The amount of carbon sequestered by
a stand of vegetation is given by tonnes of
carbon per hectare per year (tC ha
−
1
year
−
1
).
Paul et al. (
2003
)havecalculateda
fl
esh in the Indian Sundarbans
row 12 in Table
6.1
).
5. Afforestation, reforestation and (avoided)
deforestation come under the broad heading of
region (
Vide
gure of
13 tC ha
−
1
year
−
1
for commercial operations
involving Tasmanian blue-gum and radiata
pine. Hobbs and Bennell (
2005
)observedthat
Eucalyptus socialis can absorb between 2.5
and 4.2 tC ha
−
1
year
−
1
. In the present chapter,
the case study on
6
-
Table 6.2
Mean surface water salinity in three sectors of
Indian Sundarbans; each value is the mean of 6 stations
(Fig.
6.10
,
6.11
and
6.12
) and 3 seasons
Year Western
sector
Central
sector
Eastern
sector
reveals
a sequestration rate of 151.70 tC ha
−
1
year
−
1
(during 2009 at eastern sector)
Saccostrea cucullata
1990
20.25
18.03
13.78
1991
20.09
18.32
13.76
to 407.
1992
20.08
18.77
13.65
80 tC ha
−
1
year
−
1
(during 1991 at western
1993
19.87
18.92
13.51
sector) in the
eshy mass, and in the calcareous
shell, the value ranges from 479.
40 tC ha
−
1
year
−
1
(during 2009 in the eastern
sector of Indian Sundarbans) to 1407.
40 tC ha
−
1
year
−
1
(during 1991 in the western
sector). The value is much greater than the
producer community, but in reality, this does
not happen, as the biomass documented in the
present case study has not considered the full
life cycle of the oyster. If one considers the
biomass of oyster spat to adult stage, the
sequestration rate will be much lower than the
fl
1994
19.79
19.09
13.50
1995
19.76
19.21
13.38
1996
19.61
19.37
13.33
1997
19.50
19.50
13.25
1998
19.40
19.64
13.16
1999
19.30
19.79
13.08
2000
19.03
19.90
12.95
2001
18.87
20.00
12.87
2002
18.89
20.13
12.77
2003
18.71
20.22
12.65
2004
18.61
20.34
12.60
2005
18.25
20.46
12.55
gures stated here. However, the present study
suggests that one possible method for achiev-
ing the removal of carbon from the ocean and
estuaries may be through the practice of
shellsh farming.
6. The main advantage of oyster farming is that
unlike other ocean sequestration techniques,
the oyster shell permanently removes carbon
2006
18.21
20.56
12.48
2007
18.03
20.70
12.40
2008
18.01
20.85
12.31
2009
17.90
20.95
12.21
2010
17.80
21.07
12.08
2011
17.60
21.16
11.58
2012
17.34
21.27
11.44
