*3.1. BM1 Isolation and Obtaining of Its Culture*

Samples were collected from red-colored bath tiles filled with semi-saline water found in the supralittoral zone of the Kost'yan Island (66°29ȝ47Ȟ N, 33°24ȝ22Ȟ E) in the White Sea. Water samples and red plaque (Figure 1b) scrapings from the surface of parched "bath-tile" mud cracks were collected in June–August of 2011 and 2012. The samples were sealed in sterile polypropylene 

bags. Within three hours, the precipitate of the water samples was transferred to two mL of BG-11 medium [24]. The plaque scrapings were transferred in five mL of BG-11 in sterile 15 mL glass vials. Samples were incubated in 15 mL sterile glass vials at 20 °C under daylight for one month. Algological pure cultures were obtained at Pertsov White Sea Biological Station of Moscow State University. Single red-colored cells and sporangia were placed in five mL of BG11 in sterile tubes using a micromanipulator and incubated under a white fluorescent lamp (40 ΐE·mƺ2·sƺ1) at room temperature for one month. The resulting cultures were inoculated onto Petri dishes with solidified BG11 medium (containing 2% agarose) using a dilution method and incubated under the same conditions until green-colored colonies became apparent (2–3 weeks). The colonies were transferred to the tubes containing sterile BG-11 medium and incubated under the same conditions. 
