This dataset is a collection of averaged acid-corrected Chlorophyll a (Chla) and phaeopigments, and inorganic nutrient measurements taken as part of the A-TWAIN project during a cruise onboard RV Lance in September 2012, covering the Atlantic Water inflow region north of Svalbard. Water samples were taken from the CTD rosette at 11-12 depths throughout the water column for determination of Chla, and inorganic nutrients (nitrate plus nitrite (NO3− plus NO2−), phosphate (PO43-) and silicic acid (Si(OH)4 )/silicate (SiO2);concentrations in mmol m−3). For Chla, triplicates of 200 ml were filtered onto GF/F glass microfiber filters (Whatman, England) and 10 µm Isopore membrane polycarbonate filters (Millipore, USA), and frozen until further processing back in the laboratory at UiT The Arctic University of Norway. At UiT, samples were extracted in 5ml of methanol in darkness at 4C for ca. 24 h (Holm-Hansen and Riemann, 1978) and measured with a 10-AU Turner fluorometer (Turner, USA). For inorganic nutrients, water samples of 200 mL were collected in acid-washed plastic bottles or in new and rinsed falcon tubes (3x 50 ml) and immediately frozen at -20C until further processing. Following standard methods (Grasshoff et al., 2009) back in the laboratory at UIT The Arctic University of Norway (Tromsø), three replicates were analyzed for each sample. Samples were measured with a Flow Solution IV Analyser (OI Analytical, USA) calibrated with reference sea water (Ocean Scientific International Ltd., UK). The detection limits were 0.02 mmol m−3 for nitrate plus nitrite, 00.1 mmol m−3 for phosphate and 0.07 mmol m−3 for silicic acid. The study was funded by the Fram Centre project A-TWAIN, project no. 66050.
Holm-Hansen, O., Riemann, B., 1978. Chlorophyll a determination: improvements in methodology. Oikos 30, 438–447. https://doi.org/10.2307/3543338. Grasshoff, K., Kremling, K., Ehrhardt, M., 2009. Methods of Seawater Analysis. John Wiley&Sons, Edition 3, pp. 632
Version history
- Version 1 (2023-11-30): Data publicly available