A method for removing a gas from a site comprising placing cells having gas vesicles under conditions that induce the cells to float to a surface of an aqueous medium, harvesting the cells from the surface of the medium, lysing the cells, separating the gas vesicles from the lysed cells, crosslinking the gas vesicles with a crosslinking agent, loading a gas with a lowered partial pressure for the compound to be removed into the gas vesicles, and placing the gas vesicles such that the gas compound is removed from the site. Harvesting gas-vesicle-containing cells is achieved by placing the cells under conditions that induce the cells to rise to the surface of an aqueous medium—such as darkness, exponential growth stage, flocculation, or dissolved gas flotation—then collecting the cells from the surface of the medium. Gas vesicles are isolated by lysing the cells and separating the gas vesicles from the lysate. Once the gas vesicles are isolated, they can be modified, such as by crosslinking with glutaraldehyde.