Haloquadratum walsbyi plays an important ecological role in high-salt content habitats. The genome sequence gives insight in the molecular, ecological & physiological properties of the organism, including its square shape and its ability to survive in the hyper-saline environments it is found in and the high UV radiation it is exposed to.
Ecosystems (both natural and man-made) in which sea water evaporates cause the concentration and precipitation of the compounds calcium carbonate and calcium sulphate. This leaves behind a hyper-saline brine that is rich in sodium chloride (salt). These crystalliser ponds further evaporate and concentrate the brines, causing the precipitation of sodium chloride. Dense magnesium chloride brine then develops, but at the last stage of the formation of halite, Haloquadratum walsbyi is seen dominating the ponds. At this point, Haloquadratum walsbyi constitutes up to 80% of the microbial biomass. The fact that Haloquadratum walsbyi is found in such environments (and thrives here) and cannot be cultivated unless in medium that contains a high molarity of MgCl and NaCl indicates its status as one of the most halophilic organisms.
Haloquadratum walsbyi comes under the Halophile group and in their ecosystem, Halophiles are a part of the food chain and are consumed by filter feeders. Very little is known about the Halophiles roles in the environment and more research is needed.