Description: At approximate every degree, water samples to measure C assimilation rates were taken from the clean underway flow through system (intake at 6m). Triplicate incubation bottles were inoculated with 20 µmol/L of NaH13CO3. All polycarbonate incubation bottles were acid rinsed three times, rinsed two times with deionized water, and rinsed three times with seawater directly from the sample point prior to incubation. Samples were incubated for 24 hours. C assimilation rates experiments were terminated by filtering each bottle (pressure drop 〈10 kPa) through a 25 mm precombusted GF/F filter. Natural abundance samples for particulate organic carbon, used as t-zero values, were obtained by filtering 4 L water samples onto pre-combusted GF/F filters. All filters were snap frozen in liquid N and stored at -80 °C. Back on land, the filters were acidified and dried overnight at 60 °C. Samples were analysed at the Isotopic Laboratory at UC Davis, California, with an Elementar Vario EL Cube or Micro Cube elemental analyser (Elementar Analysensysteme GmbH, Hanau, Germany), interfaced to a PDZ Europa 20-20 isotope ratio mass spectrometer (Sercon Ltd., Cheshire, UK). The external error of analyses was 0.2 per mil for d13C. C fixat assimilation ion rates (rho in nmol/L/h) were calculated following Dugdale and Goering (1967) and Knap et al. (1996).

Description: Phytoplankton size classes or functional types calculated from diagnostic pigments according to Hirata et al. (2011)

Description: Pigment data from the RV Southern Surveyor expeditions: SS2012_v04, SS2012_T06 and SS2012_v04 We analysed patterns in phytoplankton community composition as indicated by the pigment composition. For pigment analysis 4L water was filtered through 25mm Whatman GF/F filters using gentle vacuum filtration with a pressure drop of less than 10 kPa. Samples were snap frozen in liquid nitrogen and stored at -80°C prior to analysis on land. Pigments were analysed using High Performance Liquid Chromatography (HPLC) according to the CSIRO method see Hooker et al. (2012) at the CSIRO laboratories in Hobart. Biochemical data are stored at the Marlin CSIRO database: http://www.marlin.csiro.au/geonetwork/srv/eng/search#fast=index&from=1&to=10&hitsperpage=10

Description: For pigment analysis 4L water was filtered through 25mm Whatman GF/F filters using gentle vacuum filtration with a pressure drop of less than 10 kPa. Samples were snap frozen in liquid nitrogen and stored at -80°C prior to analysis on land. Pigments were analysed using High Performance Liquid Chromatography (HPLC) according to the CSIRO method see Hooker et al. (2012) at the CSIRO laboratories in Hobart. For chlorophyll a analysis, 0.525 L of sample water was gently filtered via vacuum filtration (pressure drop 〈 10 kPa) on 25 mm Whatman GF/F filters. Chlorophyll a extractions were carried out following acidification according to Parsons et al. (2013). Samples were measured on a Turner Trilogy laboratory fluorometer.

Description: The international GO-SHIP repeat global survey network is a programme designed to monitor ocean change and variability. In 2016, we followed the line P15S from the ice edge to the equator along 170°W in the South Pacific Ocean. Key oceanographic features included crossing of the subtropical front (STF), from the subantarctic waters towards the oligotrophic tropics, and the equatorial upwelling region. We analysed patterns in phytoplankton community composition as indicated by the pigment composition, carbon fixation efficiency, and assessed their relationship to temperature, salinity and dissolved oxygen, as well as the dissolved nutrients nitrate, nitrite, phosphate and silicate. For pigment analysis 4L water was filtered through 25mm Whatman GF/F filters using gentle vacuum filtration with a pressure drop of less than 10 kPa. Samples were snap frozen in liquid nitrogen and stored at -80°C prior to analysis on land. Pigments were analysed using High Performance Liquid Chromatography (HPLC) according to the CSIRO method see Hooker et al. (2012) at the CSIRO laboratories in Hobart. For chlorophyll a analysis, 0.525 L of sample water was gently filtered via vacuum filtration (pressure drop 〈 10 kPa) on 25 mm Whatman GF/F filters. Chlorophyll a extractions were carried out following acidification according to Parsons et al. (2013). Samples were measured on a Turner Trilogy laboratory fluorometer. At approximate every degree, water samples to measure C assimilation rates were taken from the clean underway flow through system (intake at 6m). Triplicate incubation bottles were inoculated with 20 µmol/L of NaH13CO3. All polycarbonate incubation bottles were acid rinsed three times, rinsed two times with deionized water, and rinsed three times with seawater directly from the sample point prior to incubation. Samples were incubated for 24 hours. C assimilation rates experiments were terminated by filtering each bottle (pressure drop 〈10 kPa) through a 25 mm precombusted GF/F filter. Natural abundance samples for particulate organic carbon, used as t-zero values, were obtained by filtering 4 L water samples onto pre-combusted GF/F filters. All filters were snap frozen in liquid N and stored at -80 °C. Back on land, the filters were acidified and dried overnight at 60 °C. Samples were analysed at the Isotopic Laboratory at UC Davis, California, with an Elementar Vario EL Cube or Micro Cube elemental analyser (Elementar Analysensysteme GmbH, Hanau, Germany), interfaced to a PDZ Europa 20-20 isotope ratio mass spectrometer (Sercon Ltd., Cheshire, UK). The external error of analyses was 0.2 per mil for d13C. C fixat assimilation ion rates (rho in nmol/L/h) were calculated following Dugdale and Goering (1967) and Knap et al. (1996).