Biological and chemical water properties measured during POSEIDON cruise POS501 in Madeira basin in June 2016

During the cruise POS501 on board the German R/V Poseidon, we collected water with a CTD SBE9plus equipped with 14 Hydrobios free flow bottles of 5 L each in 24 stations (resulting in more than 300 samples) and during transect time in the Madeira basin region, Northeast Atlantic. We aimed to study the physical and biogeochemical conditions in the upper 2000 m of the water column around the catchment area of Kiel 276 in June 2016. We measured concentrations of chlorophyll a, phaeopigments, suspended particulate material (SPM) and nutrients as nitrate, nitrite, phosphate and silicate. Also, we determined concentrations of particulate organic carbon (POC) and particulate organic nitrogen (PON) as well as dissolved organic carbon (DOC) and dissolved nitrogen (DN). The physical oceanography during the survey is available at PANGAEA (https://doi.org/10.1594/PANGAEA.949134). Brief description of the methodology used: - Nitrate, nitrite, phosphate and silicate were measured by continuous flow analysis. - Oxygen was measured on one sample at each station by potentiometric Winkler titration. - DOC and DN were measured by catalytic oxidation after filtered with GF/F-filters. - POC and PON were measured by means of an elemental analyser after filtered with pre-combusted GF/F-filters. - Suspended particulate material (SPM) was determined gravimetrically after pre-combusted and weighted GF/F-filters filtration. - Chlorophyll a and phaeopigments were measured using a fluorometer after ethanol extraction of the GF/F-filters.