WET SEASON CHLOROPHYLL a, b AND PHAEOPHYTIN a LEVELS IN THE WESTERN LAGOS LAGOON AND ITS CREEKS.

Algae are known to contain a wide array of pigments that absorb light for photosynthesis and which are useful in measuring primary production levels. In this study, the levels of these algal pigments (Chlorophyll a, b and phaeophytin a) in the Lagos lagoon and adjoining creeks were investigated in relation to water chemistry of the water bodies. Fifteen sampling stations including four of the creeks were investigated for the study. For the creeks, chlorophyll a ranged from 9.6 to 23.3?g/L, chlorophyll b, 0.4 1.1ug/L and phaeophytin a, 1.1 2.9?g/L. For the open lagoon areas chlorophyll a ranged between 8.9 and 11.8?g/L, chlorophyll b, between 0.6 and 1.1ug/L and phaeophytin a between 0.7 and 3.4?g/L. The Pearson correlation co efficient matrix among chlorophyll a, b and phaeophytin a were all positive (r = 0.28 0.35). The positive correlation among all the three algal pigments points to their direct relationship. Chlorophyll a was negatively correlated with salinity. The levels of algal pigments increased as Nitrate (nutrient) and Total Suspended Solids increased, however chlorophyll a was negatively correlated with salinity and was higher in the creeks than the lagoon. Salinity was a limiting factor to algal production in the Lagos lagoon (especially in the wet season) chiefly because most phytoplankton forms at this time were (freshwater forms). Chlorophyll b levels indicated the presence of green algae and euglenoids within the study area. Phaeophytin a also increased with increasing floodwater inputs reflected by its correlation with Nitrate and Total Suspended Solids or detrital materials (r = 0.44, 0.60). The measurement of phytopigment content could also be a useful tool in the establishment of eutrophic levels within within aquatic ecosystems in Nigeria, particularly the Lagos lagoon complex