Nutrient Data for cruise DANA 6/21 (18 - 28 July 2021)

Water column samples were taken at 25 stations as conductivity-temperature-depth (CTD) casts along five transects during ten consecutive sampling days between 18 and 28 July 2021 on board RV Dana (DANA 6/21). Samples were collected in 10 L metal-free Niskin water samplers (Ocean Test Equipment; Fort Lauderdale, USA). Water samples for nutrient analysis were collected in acid-washed 100 mL HDPE (high-density polyethylene) bottles. The bottles were preconditioned three times with sample water before being filled. The samples were stored frozen at -20°C without filtration until analysis.

Nitrite, phosphate, and silicate were measured on a SmartChem 200 discrete analyser (AMS Alliance, Rome, Italy) following the reagent concentrations for the manual method in Hansen and Koroleff (1999), with the inclusion of a 150 g L^-1 solution of sodium dodecylsulfate as a dispersant for phosphate analysis. Nitrate was measured following the vanadium chloride reduction technique described by Schnetger and Lehners (2014). Community reference material for nutrients in seawater supplied by Kanso Technos Co. LTD, Japan, was used for quality control.

Hansen, H.P., Koroleff, F., 1999. Determination of nutrients, in: Grasshoff, K., Kremling, K., Ehrhardt, M. (Eds.), Methods of Seawater Analysis. Wiley-VCH Verlag GmbH, Weinheim, Germany, pp. 159–228. https://doi.org/10.1002/9783527613984.ch10

Schnetger, B., Lehners, C., 2014. Determination of nitrate plus nitrite in small volume marine water samples using vanadium(III)chloride as a reduction agent. Marine Chemistry 160, 91–98. https://doi.org/10.1016/j.marchem.2014.01.010