TD casts from surface to near-bottom or about 200 m (whichever was shallower) were collected using a Sea-Bird SBE 25 CTD (conductivity-temperature-depth) profiler with an automatic firing mechanism (AFM) water-bottle rosette lowered at 20 m/min. Single, pumped temperature, salinity and chlorophyll fluorescence sensors collected data at 4 Hz. Data were averaged into 1-decibar pressure bins. Sea Bird gives the temperature and conductivity accuracy of 0.002 degrees C and 0.0003 S/m, respectively. On each cast, Niskin bottles collected discrete water samples at 5, 15, 25, 35, 50, 75 and 100 m depth for nutrient concentrations. Chlorophyll samples were taken from the bottle depth nearest the chlorophyll maximum, usually in the upper 35 m. Salinity samples were taken alternately at the shallowest and deepest bottle depth for calibration with the CTD.
For CTD casts 21-27, the CTD rosette stopped working owing to computer communication problems. For these casts, an SBE 25 CTD without oxygen sensor or rosette was used. In those cases, one Niskin bottle was tripped at 15 m.