Spatio-temporal variability in surface Chlorophyll distribution in the Central Great Barrier Reef as derived from CZCS imagery

Abstract

A series of Coastal Zone Colour Scanner (CZCS) images has been used to compare the surface phytoplankton variation in the central Great Barrier Reef waters over the period 1979-81. Near- concurrent field data have been obtained for all the scenes so that approximate chlorophyll concentrations have been applied in the image classification. A consistent feature in the dry-season chlorophyll distribution is a cross shelf gradient with high chlorophyll levels inshore and lower levels in the mid-lagoonal waters increasing to higher concentrations in the reef matrix. The effects of higher nutrient loads in the wet season are also evident, although correlation between riverine discharge and phytoplankton abundance in the lagoon is problematic. In fact, a large scale 'bloom' event occurs before the start of the 1980-81 wet season and may be related to wind resuspension of sedimentary nutrients.