Abstract:
Background: The Jaffna lagoon is one of the key marine resources in the Jaffna Peninsula,
which provides habitat for a number of fauna and flora, livelihood support for fishing
communities in the area and seafood for the local population. However, a comprehensive study
on its mud quality has not been reported so far.
Objectives: The present study assessed the spatial and seasonal variations in mud quality of
the Jaffna lagoon to support the upcoming development efforts in the region while ensuring the
sustainability and resilience of the Jaffna lagoon ecosystem.
Methods: Mud samples were collected at 30 different geographical locations in the Jaffna
lagoon along the coastline from Ponnalai to Kilaly during the period from December 2018 -
June 2019, covering both dry and wet seasons, and the selected physicochemical parameters
were determined adopting the standard analytical methods. The obtained data were statistically
analysed by t-test and correlation coefficient analysis using SPSS software.
Results: The lagoon mud samples analysed during the study period covering both seasons
revealed the following range of variation for each physicochemical parameter studied: lagoon
depth 13-127 cm; pH 6.96-8.82; EC 11.90-108.05 mS/cm; salinity 6.35-65.60 g/kg; sulfate
793-6,250 mg/kg; phosphate 0.00-10.95 mg/kg; alkalinity 825-3,300 mg/kg; and hardness
1,750-14,000 mg/kg. Though some degree of seasonal variation was witnessed for each quality
parameter, EC, salinity and sulfate showed significant differences between the wet and dry
seasons (P <0.05) while an insignificant difference was observed with respect to pH, phosphate,
alkalinity and hardness. In the dry season, all parameters, except phosphate, negatively
correlated with lagoon depth while a positive correlation was found with respect to pH and
phosphate in the wet season. In terms of spatial variation in the mud quality, a high
concentration of phosphate was detected in locations where the stormwater carrying detergents
and agrochemicals drains into the lagoon.
Conclusion: The study reveals the patterns of spatial and seasonal variations in mud quality of
the Jaffna lagoon and helps to understand how the resourceful lagoon could be efficiently
utilized for various economic development activities based on these findings without
compromising its productivity, biodiversity and sustainability.
