the reason "dunaliella" is able to be so halo-tolerant is due to its very effective osmoregulatory process. firstly, the lack of cell wall allows the cell to easily expand and contract to maintain liveable internal salt concentrations. secondly, when triggered by the changes in cell volumes and in levels of inorganic phosphate and ph following osmotic shock, plasma membrane sensors and various soluble metabolites activate glycerol synthesis. either produced via photosynthesis or starch degradation, intracellular glycerol allows the cells to adapt to the high osmotic stress by counterbalancing the external and pressures and thus, preventing cell swelling.