Figure 1.

Schematic diagram of the fractionation protocol. First, the PW is extracted from the sediment using a Steriflip filtration unit (60 μm pore size). Then, the LA cells are separated from the firmly attached cells by shaking the grains in ASW on a BioShake iQ mixer at 1000 rpm for 40 s, followed by filtration of the supernatant through a Steriflip filtration unit after each round of shaking. The shaking procedure is repeated for a total of six rounds, and the supernatants are pooled. The firmly attached fraction are the cells remaining on the grains after the six rounds of shaking.