Abstract:
A vast area of mangrove in Can Gio Mangrove Biosphere Reserve was
destroyed by a typhoon named Durian in December 2006. After the
typhoon, trunks, branches and twigs were left on the spot. The
decomposition of these materials was expected to affect the nutrient
dynamics in the mangrove sediment and tidal creek. Therefore, this
research was conducted to study the phosphorus dynamics in a tidal creek
and test if this mangrove functions as a source or a sink of phosphorus for
its adjacent river.
The surface water and floating litter were taken during 24 hours on spring
tide from a tidal creek connecting the mangrove and its adjacent river.
The physicochemical properties of the creek water were measured directly
in field. The content of soluble reactive phosphorus (SRP), total
particulate phosphorus (TPP), and phosphorus (P) content in the floating
litter were determined to calculate the amount of P exchanged between
the mangrove and river. Map Info Professional was used to calculate the
cross-section area of the creek and the data analysis was performed with
SG Plus Centurion XVI.
Most of the floating litter were twigs and small wood pieces from the
mangrove (62% of the total weight of floating litter). The average amount
of floating litter exported from the mangrove was 305.83 gh-1
. The
average amount of P exported from the mangrove through the floating
litter was 452.3 mgh-1
. SRP in the creek derived from the higher nutrient
concentration pore-water from the mangrove sediment which came into
the creek during the ebb. The amount of P entering the mangrove was
2013.56 gday-1
, while the amount of P exported from the mangrove was
2232.78 gday-1
. Due to the decomposition of trunks and branches
remained on the mangrove floor after the typhoon, the disturbed
mangrove functioned as a source of P for its adjacent river.
