In order to assess the effect salinities and time points on bacterial cell density on surface of the alga, epibacterial cell density from T1 and T2 (n=5 for each salinity level and each time point) was determined via fluorescence microscopy of DAPI-stained bacterial cells. Epibacterial cell density samples from T0 were generated from 5 individuals prior to start of the treatment to obtain cell density values from T0. For methodological details, see Appendix S1 in supplementary information. Briefly, the bacteria attached to the surface of a defined quantity of Agarophyton were suspended in seawater via sonification and vortexing with sterile glass beads. The cells were then enriched on nitrocellulose filters, stained using standard techniques, and counted under epifluorescence microscopy, and the results were standardized based on the sampled thallus area.

T0=timepoint in May 2015T1=timepoint in August 2015T2=timepoint in Oct 2015

Supplement to: Saha, Mahasweta; Künzel, Sven; Meichssner, Rafael; Neulinger, Sven C; Petersen, Finn Ole; Weinberger, Florian (2020): Salinity and Time Can Alter Epibacterial Communities of an Invasive Seaweed. Frontiers in Microbiology, 10