Ferdelman, Timothy G; Klockgether, Gabriele; Imhoff, Kirsten; Mohrholz, Volker (2021): Meteor Expedition M148/2 EreBUS nutrient data from Benguela Upwelling System and Angola Gyre [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.931090

Nutrient data are from Nisken Bottle samples collected and measured onboard Meteor Expedition 148/2 “EreBUS”. Concentrations of dissolved inorganic phosphate (PO4), nitrite (NO2), NOx (nitrate+nitrite), and dissolved silicate (Si) were measured with the QuAAtro39 autoanalyser (Seal Analytical) using the method based on Strickland and Parsons, 1972. OSIL Seawater Low-Nutrient Standards were employed as secondary standards to check primary standard calibrations. Nitrate values are the calculated difference between NOx and nitrite. To determine Minimal Quantifiable Limit (MQL) for NOx, nitrite, phosphate and silicate we examined the variability (standard deviation, σ) around OSIL low-nutrient seawater concentrations and set MQL = 0 + 3σ. Ammonium (NH4+) was measured shipboard using the ortho-Phthaldialdehyde (OPA) fluorescence method (Holmes et al. 1999). MQLs for the offshore stations were based on values that fell below zero after calculating the concentration based on the calibration curves established for each station. We used these values as true undetectable values, because the zero values established from the calibration curve blanks tended to be greater (i.e. they have residual OPA fluorescence). MQLs were established for each station based on the mean fluorescence of undetectable samples plus three times the standard deviation of those fluorescence values. Oxygen was measured on selected samples by Winkler titration for the purpose of calibrating the CTD O2 sensor data (not calibrated in this data set). Temperature, Salinity, Temperature and Dissolved Oxygen data are included for as reference bottle information and derive originally from Mohrholz, IOW data storage server :https://www.io-warnemuende.de/en_iowdb.html (Data publicly available after 20.07.2021). Related to Ferdelman et al., (2019) “EreBUS: Processes Controlling Greenhouse Gas Emmissions from the Benguela Upwelling System, Cruise No. 148/2, July 2 - July 20, 2018, Walvis Bay (Namibia) - Las Palmas de Gran Canaria (Spain) https://doi.org/10.2312/cr_m148_2