Environmental Engineering Reference
In-Depth Information
Table 3.3
Aerial extent of vegetation and other land cover in Godavari mangroves: study area (area in km
2
)
Land cover class
1977
1988
2000
2005
Area
Area (%)
Area
Area (%)
Area
Area (%)
Area
Area (%)
Dense mangrove
20.6
2.1
7.9
0.8
8.4
0.9
10.3
1.1
Open mangrove
174.2
17.9
162.3
16.7
176.8
18.2
175.7
18.1
Subtotal
194.8
20.0
170.2
17.5
185.2
19.1
186.1
19.1
Plantations
10.6
1.1
11.4
1.2
17.4
1.8
18.2
1.9
Agriculture
208.8
21.5
200.8
20.7
181.9
18.7
196.2
20.2
Built-up area
14.2
1.5
19.5
2.0
20.7
2.1
22.4
2.3
Aquaculture
0.0
0.0
17.6
1.8
54.7
5.6
46.5
4.8
Water bodies
438.2
45.1
456.0
46.9
434.0
44.7
428.8
44.1
Mud
fl
at
85.5
8.8
77.1
7.9
56.5
5.8
60.1
6.2
Sand
19.8
2.0
19.2
2.0
21.3
2.2
13.6
1.4
Grand total
972.0
100.0
972.0
100.0
972.0
100.0
972.0
100.0
1977
1988
2000
2006
Fig. 3.8
Classied vegetation and land cover maps of Godavari mangroves
(A) Aqueous Acidi
cation Procedure
In the aqueous acidi
large (50
200 mg) samples, are somewhat
tedious and cannot be easily automated.
Hedges and Stern (
1984
) described two
methodologies for the analysis of organic carbon,
total nitrogen and inorganic carbon in sediments,
sediment trap materials and plankton. Both
methods discriminate organic carbon and inor-
ganic carbon by acidi
-
cation procedure, the
wet sample is homogenized and a subsample
equivalent to 50
100 mg dry weight is weighed
into a pre-weighed 20-ml glass scintillation vial.
The sample is dried overnight at 50
-
C and
reweighed after cooling to obtain the initial dry
weight (
°
cation, avoid losses of
acid-soluble organic and inorganic matter and
require only high temperature combustion. The
two methods differ primarily in whether inor-
ganic carbon is removed by aqueous- or vapour-
phase acidi
W
o
) and the wt% water. If inorganic
carbon is to be determined (by difference), the
dried sample is powdered with an agate mortar
and pestle and 1
10 mg subsamples are weighed
out in duplicate into solvent-rinsed tin sample
boats for elemental analysis. If this is done,
-
cation.
W
o
