Hydrochemistry of water samples in the northern Benguela during METEOR expedition M120

We present data on distribution of inorganic nitrogen compounds including nitrate (NO2-) and nitrite (NO3-) in the northern Benguela and the Angola-Benguela Front regions between 10°S and 23°S. The fieldwork took place during the cruise No. M120 (Oct. 17th – Nov. 18th, 2015) onboard the R/V METEOR, which encompassed close-coastal and open ocean regions off Angola and Namibia. All nutrient samples were retrieved with the ship's CTD rosette (SBE 9+). Immediately after sampling, a volume of about 40 ml of each sample was filtered through a disposable syringe filter (CA, 0.45 µm) and filled in a pre-rinsed 50 ml PE bottle. The bottles were securely closed and kept frozen at -20°C until further analysis. The concentrations of nutrients were determined photometrically with a Skalar San++ Autoanalyzer following the procedures detailed in Grasshoff et al. (1999). For the quality control, a reference standard was also measured at regular intervals.