Predicting rates of primary production in the vicinity of the Subtropical Convergence east of New Zealand

Water column integrated productivity of phytoplankton in three water masses east of New Zealand (Subtropical, Subtropical Convergence, and Subantarcti c) varied both seasonally and spatially, ranging across two orders of magni tude. Productivity was highest in spring and autumn, and lowest in winter. Subtropical and Convergence waters were generally more productive than Suba ntarctic waters, but during summer the 2-3-fold range of production was sim ilar in each of the three water masses. Multiple regression analysis identi fied that most of the variability in production was associated with differe nces in integrated chlorophyll a concentrations (56%). By considering both surface chlorophyll a and incident irradiance we derived a relationship whi ch explained 74% of observed spatial and seasonal variability in integrated production. These surface variables can be sensed remotely, suggesting the potential for broad spatial mapping of the seasonal cycles of production i n these water masses in the New Zealand Exclusive Economic Zone (NZEEZ). Fu rther analysis of the relationship identified that most of the remaining va riability could be attributed to P-opt(b) (a temperature-dependent photo-ad aptive term). Exceptions to the relationship and the application of product ivity models within NZEEZ are discussed.