1 m ammonium acetate

Isolated phage lysates (>10⁹ PFU/mL) were precipitated by 1 M ammonium acetate (Sigma-Aldrich, USA) with centrifugation steps at 21,000 × g for 75 min. The precipitated phage particles were stained with 10 µL of 2% uranyl acetate (Sigma-Aldrich, USA) for 30 s on 200 mesh formvar carbon-coated copper grids before they were visualized through transmission electron microscopy (TEM) following an established method (14 (link)).

Two sediment samples (1 cm-depth) were collected in each plot of all the areas with a syringe (50 mL), kept in a cooler box during transport, and stored at -20°C until storage at -80°C at the laboratory. Before extraction, sediment samples were freeze-dried and homogenized. The pigments from 0.5 g of dry sediments were extracted with 5 mL of methanol buffered with 2% of 1 M-ammonium acetate (Sigma-Aldrich, France). After 2 min in an ultrasound cold bath and at maximum power, samples were kept in the dark at -20°C for 15 min before centrifugation (High Conic Rotor, Thermo Scientific, 3220 g, 2°C, and 5 min). Supernatants were collected and the pellets were re-extracted as described above. The pooled supernatants were filtered on 0.2 μm PTFE membrane syringe filter (Ø 13 mm, VWR International, United States) and stored a few days at -80°C before High Performance Liquid Chromatography (HPLC) analysis. To prevent degradation of pigments, extractions were performed under dark conditions and samples stored on ice during handling.

Isolated phage lysates (>10⁹ PFU/mL) were precipitated by 1 M ammonium acetate (Sigma-Aldrich, USA) with centrifugation steps at 21,000 × g for 75 min. The precipitated phage particles were stained with 10 µL of 2% uranyl acetate (Sigma-Aldrich, USA) for 30 s on 200 mesh formvar carbon-coated copper grids before they were visualized through transmission electron microscopy (TEM) following an established method (14 (link)).