Understanding phytoplankton variability throughout Spencer Gulf, South Australia, via satellite derived Chlorophyll-A

Abstract

MODIS chlorophyll-a imagery was analysed to better understand the dynamics of phytoplankton in Spencer Gulf, South Australia. MODIS chlorophyll-a was validated against in situ chlorophyll-a measurements to assess the performance of MODIS algorithms in this shallow coastal body of water. Monthly mean chlorophyll-a imagery was then used to study the broad-scale seasonal variability in chlorophyll-a throughout Spencer Gulf and surrounding waters. Validation showed a slight overestimation in chlorophyll-a via MODIS when concentrations were low, and also likely coastal influences upon the measurements. The validation was less than conclusive with MODIS measurements explaining just 46% of the variation in the field data. The monthly image sequences identified significant differences in seasonal chlorophyll-a characteristics between different locations within the gulf. Elevated chlorophyll-a concentrations were also observed near the southern bluefin tuna aquaculture zone during winter compared to nearby waters of southern Spencer Gulf.