PJB-2017-147
SEASONAL VARIATIONS IN POTENTIAL NITRIFICATION RATES IN MANGROVE SEDIMENT AT SANDSPIT BACKWATERS, KARACHI, PAKISTAN
YASMEEN ZAMIR AHMED, SEEMA SHAFIQUE, ZAIB-UN-NISA BURHAN, ADNAN KHAN AND PIRZADA JAMAL AHMED SIDDIQUE
Abstract
Sandspit coastal area is located between Hawksbay and Manora channel, south of Karachi. The area opposite to sandy coast is covered by mangrove forest at Sandspit backwaters. The potential nitrification rates in sediment from rhizosphere and non-rhizosphere at Sandspit backwater mangrove forest was examined using sodium chlorate inhibition method. Samples collected during pre-monsoon (Jan), monsoon (June) and post-monsoon (Nov) seasons were analyzed using two different concentration of inhibitor. The higher inhibitor concentration (30mM) was found to be more effective than lower (15mM) concentration used. The potential nitrification rates were slightly higher during monsoon as compared to other seasons. The potential nitrification values ranged from 0.06 (post-monsoon) to 1.20 mg NO2- N gw-1h-1 (monsoon). The potential nitrification rates had significant correlation with the incubation time (p<0.005, n=3). The nitrifiers in mangrove sediments appear to tolerate a range of physical and chemical parameters, such as, temperature (17-28 ºC), Salinity (36-42), pH (6.8-8.9), and DO (3.7-6.5 mg/L) and maintain steady potential nitrification rates, as observed during experimentation in two sediments types during all seasons.
To Cite this article:
Download
