Seasonal distribution of phytoplankton pigments in the estuarine system of Goa

Abstract

Seasonal changes in the concentrations of chlorophylls and carotenoid were studied in the estuarine complex of Goa at 14 stations. Annual mean concentration of chl. <i>a</i> was 3.05, 4.42 and 4.12 mg/m³ in Mandovi estuary. Cumbarjua canal and Zuari estuary respectively with a peak in May. Chl. <i>a</i> increased towards the mid reaches of Mandovi estuary. Chl. <i>b</i> ranged between 0 and 5.48 mg/m³ while chl. c varied between 0 and 10 mg/m³. Annual mean of chl.c was 2.28, 2.69 and 3.03 mg/m³ Mandovi estuary, Cumbarjua Canal and Zuari estuary respectively. Carotenoid values were low and ranged between 0 and 3.6 m-SPU/m³ with the peak in May in close relation to chl. <i>a</i>. Annual mean for Mandovi estuary, Cumbarjua canal and Zuari estuary was 1.10, 1.28 and 1.45 m-SPU/m³ respectively. Ratios of chl. c to <i>a</i> and carotenoid to chl. <i>a</i> were mostly less than unity except on few occasions. It was noticed that Mandovi waters are significantly different from those of Cumbarjua canal and Zuari estuary while no such difference was noticed between that of Cumbarjua canal and Zuari estuary indicating that the latter influences the chlorophyll concentration in the canal.