Biomass and height increment measurements
Height increments of the moss in the mesocosms were measured weekly during the incubation period (Fig. S2), using five brush wires (Rydin & Jeglum, 2013) inserted into each mesocosm container. At the end of the incubation period, biomass formed during the incubation was harvested by cutting the moss at its initial height (essentially its capitulum), based on the brush wire data. Its fresh weight was determined and the material was dried at 60°C for 48 h to determine the dry weight and subsequently the water content of the moss. The biomass production of each replicate (moss in each container) was estimated by dividing the dry weight of each replicate obtained after harvest, by its surface area (calculated based on container dimensions) and incubation time. Biomass density was calculated by dividing the dry weight of each replicate by its surface area and total height increment.