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International Journal of Marine Science 2013, Vol.3, No.16, 128-134
http://ijms.sophiapublisher.com
130
the delta. The Sundarbans, covers an area of 6 017
km
2
, of which 4 143 km
2
are landmass and remaining
1 874 km
2
are under water bodies, in form of Rivers,
canals and creeks (Karim, 1995). The coast of the
sundarban is criss crossed by a network of complex
estuarine network formed by the River Rupsha, Passur,
Shibsha, Arpangashia, Baleswar, Vola and other
Rivers which opens into the Bay of Bengal through
Sunderban Reserved Forest (SRF) and carry a large
amount of nutrients which facilitate the productivity in
the area (Chaffey and Chitkara, 1985). The River
Balaswar in the east is the main source of fresh
water although several others also bring water from
the Ganges during the rainy season. These Rivers
are therefore, more susceptible to dry season
reduction in stream flow and tidal intrusion of
saltwater (Hasan, 2001).
1.2 Sampling stations and sampling period
The water samples were collected from several
sampling points of three major River systems of
sunderbans which are given in Table 1. The sampling
period was divided into two seasons, Post monsoon
and winter. Post monsoon includes September to
November and winter includes December to February.
In post monsoon the sampling time of Passur River
was done at September, 2010. This was repeated at
November, 2010 in winter. Sampling period of
Arpangashia River was October, 2010 in post
monsoon and December, 2011 at winter. The sampling
period of Baleswar and Bhola River was during
December month and February month respectively.
1.3 Sample collection
Water samples were collected from the surface layer
of the water body with water sampler during high tide.
Water samples were collected from the Rivers at each
sample point and stored in pre-cleaned plastic
containers. The volume of containers was two liters.
Once collected, the samples were immediately
stored on ice in a cooler box and transported to the
laboratory and were stored at 4
℃
.
1.4 Total Nitrogen analysis
The Nitrogen is distilled and determined by Kjeldahl,
titration, method (Saxena, 1998) by the following
formula TON mg/L=(T-B)×N×1000×14/Volume of
sample Where, T=volume of titrant (Hcl) used against
sample (mL); B=volume of titrant (Hcl) used against
blank (mL); N=Normality of titrant (0.01); 14=
Atomic mass of Nitrogen.
1.5 Total phosphorus analysis
This ortho-phosphate can be determined by ascorbic
acid method (River Watch Network, 1991) by the
Preparation of calibration curve (Figure 2).
1.6 Data presentation
Microsoft Excel was used for the analysis and
graphing of collected data.
2 Results and Discussion
2.1 Total Nitrogen-TN
In Rupsha-Passur River system, the mean value of TN
was 2.10±0.41 mg/L in post monsoon and the mean
value of TN was 4.47±0.72 mg/L in winter season (Figure 3)
Table 1 Sampling stations and time
River System
Sampling Station
Latitude
Longitude
Rupsha-Passur (R-P)
Karamjol
22°12.295' E
89°51.883'N
Karamjol canal
22°25.737' E
89°35.447'N
Joymuni
22°21.038' E
89°37.800'N
Herbaria
22°18.000' E
89°36.536'N
Herbaria canal
22°17.826' E
89°36.891'N
Arpangashia-Malancha (A-M) Poshurtola River
22º14'°38" N
89º11'934" E
Poshurtola canal
22º14'°77" N
89º12'043"E
Kalagachi River
22º12'685" N
89º14'541"E
Kalagachi cannel
22º12'392" N
89º14'638"E
Arpangashia River
22º12'4°6" N
89º18’581"E
Baleswar-Bhola (B-B)
Bogi
22º12'54.4"N
89º50'21.9"E
Saronkhola
22º12'35.6"N
89º48'42.4" E
Supoti
22º03.442' N
89º49.07' E
Supoti cannel
22º3.128' N
89º48.93' E