238
Hooghly estuary in Indian Sundarbans was selected in the east coast and Mandovi
estuary in Goa was selected in the west coast of the country as the sampling sites.
In Indian Sundarbans, out of seven major estuaries, the Hooghly is the westernmost estuary. Four sampling stations were selected along the Hooghly estuarine
stretch in the east coast of India viz. E 1 (21°52′26.50″N and 88°08′04.43″E), E 2
(21°47′01.36″N and 88°04″52.98″E), E 3 (21°39′58.15′′N and 88°10′07.03″E) and
E 4 (21°38′54.37″N and 88°03′06.17″E) for the present study.
Goa is a maritime state in the west coast of India and has ~120 km coastline. The
coastal strip is highly indented with sea-cliffs, notches and promontories alternating
with rivers and estuaries, and bounded by the Arabian Sea on the west and by the
Sahyadri ranges on the east. The steep topography has formed fringes of intertidal
zones in the study area (12°28′–15°52′N and 73°46′–73°54′E). The coastline of
Goa is indented with seven major estuaries including Mandovi, the site of the present programme. Four stations along the Mandovi estuary namely W 1 (73°46′57.3″E
and 15°30′49.3″N), W 2 (73°52′10.6″E and 15°30′42.7″N), W 3 (73°54′06.5″E and
15°30′33.5″N) and W 4 (73°59′08.9″E and 15°30′26.4″N) were selected on the basis
of availability of the species.
In the species collected from the Hooghly estuary, the values of stored carbon in
the above ground biomass (i.e., above ground carbon or AGC) ranged from 58.33 (at
E 1 during 2002) to 104.30 gm m
−2
(at E 4 during 2011), whereas in the west coast
(along the Mandovi estuary), the values were relatively less (32.57 at W 3 during
2000 to 63.82 gm m
−2
at W 4 during 2011) (Fig. 7.51). The average carbon stored in
the above ground biomass of the species (AGC) at east and west coasts were
74.91gm m
−2
and 44.48 gm m
−2
respectively. ANOVA results also confirm significant
spatial variations in AGC between years and also between coasts (Table 7.13)
(p < 0.01).
Figure 7.52 shows the carbon content in the root system of the species, which is
referred to as below ground carbon (BGC). The BGC of P. coarctata followed the
same trend as AGC with relatively more stored carbon in the samples collected from
the mudflats in the Hooghly estuary in the east coast (47.81 at E 1 during 2008 to
63.49 gm m
−2
at E 4 during 2009) compared to the Mandovi estuary in the west coast
(26.79 at W 4 during 2006 to 54.41 gm m
−2
at W 2 during 2006). The average carbon
stored in the below ground biomass (BGC) at east and west coasts were 55.25 gm
m
−2
and 36.87 gm m
−2
respectively. ANOVA results also confirm significant spatial
variations in BGC between coasts but not between years (Table 7.13) (p < 0.01).
The relatively greater biomass of the species thriving along the Hooghly estuarine
stretch compared to Mandovi estuarine P. coarctata is the key factor behind such
spatial variation in stored carbon.
The carbon storage/sequestration profile of true mangroves and associate floral
species confirms that mangrove forests can play an important role in natural carbon
removal process practically at no cost as they are among the most carbon-dense
ecosystems in the world.
Researchers estimated the monetary value of the benefits, or “ecosystem services,” provided by mangroves at $194,000 per hectare annually. Multiplied by their
global extent, the value comes to around $2.7 trillion in services every year.
7 Mangroves: Unique Sinks of Carbon and Nitrogen
Hooghly estuary in Indian Sundarbans was selected in the east coast and Mandovi
estuary in Goa was selected in the west coast of the country as the sampling sites.
In Indian Sundarbans, out of seven major estuaries, the Hooghly is the westernmost estuary. Four sampling stations were selected along the Hooghly estuarine
stretch in the east coast of India viz. E 1 (21°52′26.50″N and 88°08′04.43″E), E 2
(21°47′01.36″N and 88°04″52.98″E), E 3 (21°39′58.15′′N and 88°10′07.03″E) and
E 4 (21°38′54.37″N and 88°03′06.17″E) for the present study.
Goa is a maritime state in the west coast of India and has ~120 km coastline. The
coastal strip is highly indented with sea-cliffs, notches and promontories alternating
with rivers and estuaries, and bounded by the Arabian Sea on the west and by the
Sahyadri ranges on the east. The steep topography has formed fringes of intertidal
zones in the study area (12°28′–15°52′N and 73°46′–73°54′E). The coastline of
Goa is indented with seven major estuaries including Mandovi, the site of the present programme. Four stations along the Mandovi estuary namely W 1 (73°46′57.3″E
and 15°30′49.3″N), W 2 (73°52′10.6″E and 15°30′42.7″N), W 3 (73°54′06.5″E and
15°30′33.5″N) and W 4 (73°59′08.9″E and 15°30′26.4″N) were selected on the basis
of availability of the species.
In the species collected from the Hooghly estuary, the values of stored carbon in
the above ground biomass (i.e., above ground carbon or AGC) ranged from 58.33 (at
E 1 during 2002) to 104.30 gm m
−2
(at E 4 during 2011), whereas in the west coast
(along the Mandovi estuary), the values were relatively less (32.57 at W 3 during
2000 to 63.82 gm m
−2
at W 4 during 2011) (Fig. 7.51). The average carbon stored in
the above ground biomass of the species (AGC) at east and west coasts were
74.91gm m
−2
and 44.48 gm m
−2
respectively. ANOVA results also confirm significant
spatial variations in AGC between years and also between coasts (Table 7.13)
(p < 0.01).
Figure 7.52 shows the carbon content in the root system of the species, which is
referred to as below ground carbon (BGC). The BGC of P. coarctata followed the
same trend as AGC with relatively more stored carbon in the samples collected from
the mudflats in the Hooghly estuary in the east coast (47.81 at E 1 during 2008 to
63.49 gm m
−2
at E 4 during 2009) compared to the Mandovi estuary in the west coast
(26.79 at W 4 during 2006 to 54.41 gm m
−2
at W 2 during 2006). The average carbon
stored in the below ground biomass (BGC) at east and west coasts were 55.25 gm
m
−2
and 36.87 gm m
−2
respectively. ANOVA results also confirm significant spatial
variations in BGC between coasts but not between years (Table 7.13) (p < 0.01).
The relatively greater biomass of the species thriving along the Hooghly estuarine
stretch compared to Mandovi estuarine P. coarctata is the key factor behind such
spatial variation in stored carbon.
The carbon storage/sequestration profile of true mangroves and associate floral
species confirms that mangrove forests can play an important role in natural carbon
removal process practically at no cost as they are among the most carbon-dense
ecosystems in the world.
Researchers estimated the monetary value of the benefits, or “ecosystem services,” provided by mangroves at $194,000 per hectare annually. Multiplied by their
global extent, the value comes to around $2.7 trillion in services every year.
7 Mangroves: Unique Sinks of Carbon and Nitrogen