The Sub-Antarctic Zone (SAZ) in the Southern Ocean provides a significant sink for atmospheric CO 2 and quantification of this sink is therefore important in models of climate change. During the SAZ-Sense (Sub-Antarctic Sensitivity to Environmental Change) survey conducted during austral summer 2007, we examined CO 2 sequestration through measurement of gross primary production rates using 14 C. Sampling was conducted in the SAZ to the south-west and south-east of Tasmania, and in the Polar Frontal Zone (PFZ) directly south of Tasmania. Despite higher chlorophyll biomass off the south-east of Tasmania, production measurements were similar to the south-west with rates

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The areal biomass productivities (g −1 m −2 day −1 ) of Nannochloropsis oceanica between different sizes of way ponds were compared. Sequential batch cultivation using 2-m 2 , 20-m 2 , and 200-m 2 raceway ponds with an industrial scale 4000-m 2 raceway as the main culture was conducted in summer and autumn during 2017 at Whyalla, Australia. Areal productivities of sequential batch cultivation during the same culture period were 8.4 g ± 0.9 g −1 m −1 day −1 in the 2-m 2 ponds, 9.3 g −1 m −1 day −1 in the 20-m 2 ponds, and 8.0 g −1 m −1 day −1 in the 200-m 2 ponds respectively. In parallel with the operation of the main 4000-m 2 pond, some smaller scale ponds of 2, 20, and 200 m 2 were operated at the same site under the same conditions. Areal productivity data of dry biomass of Nannochloropsis oceanica in each pond are very similar between industrial 4000-m 2 pond and other smaller ponds. In this work, the authors demonstrate that using the growth rate and productivities of Nannochloropsis from smaller scale open ponds with the same depth is valid to estimate for large-scale ponds in excess of 4000 m 2 .

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