Microbial cell numbers measured during POLARSTERN cruise PS94 (TransArcII) to the Barents Sea and central Arctic

For the determination of prokaryotic cell numbers, 1 cm³ sediment was fixed with sterile filtered formalin/seawater at a final concentration of 2% and stored at 4°C until further analyses in the home laboratory. Samples were filtered on 0.2 µm polycarbonate filters, stained with acridine orange (Meyer-Reil, 1983, doi:10.1007/bf00395813), and counted using an epifluorescence microscope (Axiophot II Imaging, Zeiss, Jena, Germany). For each sample, 30 random grids from two replicate filters were counted and averaged.