206
7.4.4 Role of Tides in Short Term Variation
Kristensen et al. (2008) carried out a short term monitoring in two Tanzanian mangrove forests. However, they emphasized on one of the crucial most phenomenon that
is unambiguously accepted to play a deciding role in regulating the short term variation in fluxes of CO 2 , i.e. the effect of tides. They observed a wide range of fluxes
from the water column depending upon the water level; lower effluxes were observed
during the high tide sessions and the lower effluxes were observed during the low tide
sessions. It is worth mentioning that the fluxes during low tide were almost 5–16
times higher than that observed during the high tides. Pore-water seepage along with
the supersaturated runoff the forest floor was mainly held accountable for this hike in
flux rate during the low tide, whereas, during the high tide, the dilution of the water
column with pCO 2 lean water from the sea led to the decrease in fluxes.
7.4.5 Seasonal Variability
Very few works have ever been performed on the seasonal dynamics of air-water
CO 2 exchange in the mangrove dominated waters. Konè and Borges (2008) carried
out in two mangrove forests namely Tam Giang and KiȇnVàng Mangroves during
the dry and the rainy season. In one of these mangrove forests, i.e. KiȇnVàng
Mangroves, they observed a CO 2 flux rate 5 times higher during the rainy season
compared to dry season, however, in the other mangrove forest, i.e. Tam Giang, no
such seasonal differences were observed. This contrast was explained by the authors
mainly in terms of the ΔpCO 2 and wind speed both of which were substantially high
in the KiȇnVàng Mangroves during rainy season but no seasonal difference of these
aspects were seen in Tam Giang Mangroves.
A noticeable enrichment of total suspended matter (TSM) indicating in turn substantial increase in the organic load and leading to net heterotrophic conditions was
observed in KiȇnVàng Mangroves, however, such a phenomenon was found to take
place in the Tam Giang Mangroves. Thus this observation teaches us that seasonality should not be expected to behave in a similar fashion in all the mangroves of the
world.
Linto et al. (2014) carried out a seasonal study in the Wright Myo and Kalighat
mangrove forests of Andaman Islands and their observations were mostly similar to
that of Konè and Borges (2008). Two to five fold rise in air-water CO 2 fluxes were
observed during the wet season (i.e. during the peak of southwest monsoon) accompanied by four fold rise in the turbidity of the water column leading to enhanced net
heterotrophy. The range of the magnitude of fluxes was comparable to that observed
in the other mangroves.
In the Everglades mangrove forest, Ho et al. (2014) observed the largest flux
rates (10.2 ± 1.0 g CO 2 m
−2
day
−1
) compared to all the magnitudes tabulated in
Table 7.3. However, Troxler et al. (2015) while working in the same region in the
A. Akhand et al.
7.4.4 Role of Tides in Short Term Variation
Kristensen et al. (2008) carried out a short term monitoring in two Tanzanian mangrove forests. However, they emphasized on one of the crucial most phenomenon that
is unambiguously accepted to play a deciding role in regulating the short term variation in fluxes of CO 2 , i.e. the effect of tides. They observed a wide range of fluxes
from the water column depending upon the water level; lower effluxes were observed
during the high tide sessions and the lower effluxes were observed during the low tide
sessions. It is worth mentioning that the fluxes during low tide were almost 5–16
times higher than that observed during the high tides. Pore-water seepage along with
the supersaturated runoff the forest floor was mainly held accountable for this hike in
flux rate during the low tide, whereas, during the high tide, the dilution of the water
column with pCO 2 lean water from the sea led to the decrease in fluxes.
7.4.5 Seasonal Variability
Very few works have ever been performed on the seasonal dynamics of air-water
CO 2 exchange in the mangrove dominated waters. Konè and Borges (2008) carried
out in two mangrove forests namely Tam Giang and KiȇnVàng Mangroves during
the dry and the rainy season. In one of these mangrove forests, i.e. KiȇnVàng
Mangroves, they observed a CO 2 flux rate 5 times higher during the rainy season
compared to dry season, however, in the other mangrove forest, i.e. Tam Giang, no
such seasonal differences were observed. This contrast was explained by the authors
mainly in terms of the ΔpCO 2 and wind speed both of which were substantially high
in the KiȇnVàng Mangroves during rainy season but no seasonal difference of these
aspects were seen in Tam Giang Mangroves.
A noticeable enrichment of total suspended matter (TSM) indicating in turn substantial increase in the organic load and leading to net heterotrophic conditions was
observed in KiȇnVàng Mangroves, however, such a phenomenon was found to take
place in the Tam Giang Mangroves. Thus this observation teaches us that seasonality should not be expected to behave in a similar fashion in all the mangroves of the
world.
Linto et al. (2014) carried out a seasonal study in the Wright Myo and Kalighat
mangrove forests of Andaman Islands and their observations were mostly similar to
that of Konè and Borges (2008). Two to five fold rise in air-water CO 2 fluxes were
observed during the wet season (i.e. during the peak of southwest monsoon) accompanied by four fold rise in the turbidity of the water column leading to enhanced net
heterotrophy. The range of the magnitude of fluxes was comparable to that observed
in the other mangroves.
In the Everglades mangrove forest, Ho et al. (2014) observed the largest flux
rates (10.2 ± 1.0 g CO 2 m
−2
day
−1
) compared to all the magnitudes tabulated in
Table 7.3. However, Troxler et al. (2015) while working in the same region in the
A. Akhand et al.