EFFECT OF CRUDE OIL ON THE BIOSYNTHESIS OF CHLOROPHYLL-A AND PHAEOPIGMENT BY ESTUARINE MICROALGAL BIOFILMS IN THE WETLAND

ABSTRACT Four separate mesocosm-based Experiments (A-D) were carried out over a period of four months involving impactation of microalgal mats in cores at two levels of PHC concentrations and nutrient enrichment with nitrate and phosphate at three levels of concentrations. Two sets of experiments were set up; in the light and in the dark. The effect of maximum enrichment in increasing CHL-a biosynthesis in the dark was observed at low and high oil impactation from the effect of periodic variation (P = <0.001). Values ranged from 5.9 -59.5 µg g -1 of sediment at low and high oil-spiking. After correction to percent baseline value, at low oil spiking, CHL-a was better synthesized in the light than in the dark. At higher oil impactation it appears CHL-a was better synthesized in the oil-spiked controls in the dark especially and also and in the light which were respectively 240 and 180% higher than the baseline values. The typical biofilm response to contaminants in the environment appear to have been exhibited in which they were sequestered and made non-available for biodegradation in the absence or reduced mineral enrichment. In this case oil KIGIGHA, UNDERWOOD, 2013: 1 (6) AJRC.JOURNAL@GMAIL.COM 19