able to eliminate elevated nitrate concentration
through the denitrification pathway.
Conclusion
The Divar mangrove sediments harbored sufficient
amount of labile organic matter to support
denitrification activity. Microcosm experiments
have indicated that nitrate addition enhanced denitrification
at in situ organic carbon concentration.
The benthic denitrifying community in these habitats
respond rapidly to episodic events of elevated
nutrient supply by increasing the rate of nitrate removal
through the denitrification pathway. Thus,
these sediments could act as a sink for nitrate and
this nutrient is more crucial in controlling denitrification
activity. Potential denitrification rates
were up to 38 times higher than the in situ denitrification
activity indicating that the process was
important in maintaining low concentration of nitrate
and helps to maintain the water quality of the
adjoining aquatic system.
Acknowledgements The authors thank Dr. S.R. Shetye,
Director, NIO, for the facilities. Sheryl is thankful to the
Council of Scientific and Industrial Research (Government
of India) for the award of Senior Research Fellowship.
Dr. Prabhat Gupta (NPL, New Delhi) is acknowledged for
providing the N2O standard. This is NIO contribution no.
4688.