Microbial and molecular description of the sea surface microlayer off Mauritania during POSEIDON cruise POS519, Jan/Feb 2018

Data were collected off Mauritania in January and February 2018 from board the RV Poseidon inside and outside a recently upwelled filament propagating offshore. To sample the Sea Surface Microlayer (SML), a depth of approx. 0.5mm, we used a screen sampler (Garrett 1965). As reference, samples from the underlying water (ULW) from the ships inlet at 2m depth were collected. Data provide information about the molecular and microbial composition of the SML including amino acids, carbohydrates, and flow cytometry data. The concentration of surface active substances was assessed by AC phase sensitive voltammetry and are expressed as Triton-X equivalents. Sea surface temperature, salinity and further weather data were obtained from the on-board ships weather station.