International Journal of Marine Science 2015, Vol.5, No.16, 1-12
4
The pH varied from 7.6 to 8.2 and the pH level
increased from the minimum values recorded during
the monsoon season at station 1 to reach the maximum
during pre-monsoon (Figure 2). Hydrogen ion
concentration (pH) in surface waters remained
alkaline at all sites throughout the study period, with
the maximum value during summer season and the
minimum during monsoon. Generally, fluctuations in
pH values during different seasons of the year are
attributed to factors like removal of CO
2
by
photosynthesis through bicarbonate degradation,
dilution of seawater by freshwater influx, reduction of
salinity and temperature, and decomposition of
organic matter (Rajasegar, 2003).
Nutrients are considered as one of the most important
parameters in the marine environment influencing
growth, reproduction and metabolic activities of biotic
components. In the same way, environmental
parameters are key factors in the decomposition
process of organic matter (Sangiorgio et al
.,
2008).
Distribution of nutrients is mainly based on season,
tidal conditions and freshwater flow from land. The
environmental chemical characteristics of the surface
sea water maximum during monsoon and the
minimum in the summer. The nitrite values ranged
between 0.293 and 1.447 µmol l
-1
(Figure 2). The
nitrate values ranged between 2.736 and 10.26 µmol
l
-1
(Figure 3). The ammonia values ranged between
0.048 and 0.254 µmol l
-1
(Figure 3). The total nitrogen
values ranged between 11.024 and 12.368 µmol l
-1
(Figure 3)
.
In the present study highest values of
nitrate and total nitrogen during monsoon season
could be mainly due to the organic materials received
from the catchment area during ebb tide (Ashok Prabu
et al., 2008). Another possible way of nitrate input
could be through oxidation of ammonia form of
nitrogen to nitrite formation (Rajasegar, 2003). The
recorded low values during non-monsoon period may
be due to its utilization by phytoplankton as evidenced
by high photosynthetic activity and the dominance of
neritic seawater having a negligible amount of nitrate
(Rajaram et al., 2005; Bragadeeswaran et al., 2007).
Figure 3 Water quality parameters Nitrate, Ammonia, Total nitrogen, Inorganic phosphate Total phosphorus and silicate present in the
study period
The inorganic phosphate values ranged between 0.268
and 0.989 µmol l
-1
(Figure 3)
.
The total phosphorus
values ranged between 0.617 and 2.466 µmol l
-1
(Figure 3)
.
Present study maximum level of inorganic
phosphate and total phosphorus were recorded during
monsoon season and the minimum values were
noticed in summer period. High concentration of
inorganic phosphate observed during monsoon season
