کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4532594 | 1325134 | 2011 | 12 صفحه PDF | دانلود رایگان |
Phytoplankton biomass and primary production were monitored in the Hauraki Gulf and on the northeastern continental shelf, New Zealand – using ship surveys, moored instruments and satellite observations (1998–2001) – capturing variability across a range of space and time scales. A depth-integrated primary production model (DIM) was used to predict integrated productivity from surface parameters, enabling regional-specific estimates from satellite data. The shelf site was dominated by pico-phytoplankton, with low chlorophyll-a (<1 mg m−3) and annual production (136 g C m−2 yr−1). In contrast, the gulf contained a micro/nano-phytoplankton-dominated community, with relatively high chlorophyll-a (>1 mg m−3) and annual production (178 g C m−2 yr−1). Biomass and productivity responded to physico-chemical factors; a combination of light, critical mixing depths and/or nutrient limitation—particularly new nitrate-N. Relatively low biomass and production was observed during 1999. This coincided with inter-annual variability in the timing and extent of upwelling- and downwelling-favourable along-shelf wind-stress, influencing the fluxes of new nitrate-N to the shelf and gulf. Relationships with the Southern Oscillation Index are also discussed. Our multi-scaled sampling highlighted details associated with stratification and de-stratification events, and deep sub-surface chlorophyll-a not visible to satellite sensors. This study demonstrates the importance of multi-scaled sampling in gaining estimates of regional production and its responses to physico-chemical forcing.
► Ship, mooring and remote sensing of phytoplankton biomass and primary production.
► Depth Integration Model predicts integrated productivity.
► Seasonal and inter-annual variability relates to physico-chemical forcing.
► New nitrogen supply controlled by timing and extent of upwelling events.
► Climatic changes in wind-stress on upwelling links to biomass and production.
Journal: Continental Shelf Research - Volume 31, Issue 17, 1 November 2011, Pages 1799–1810