Although Thiomargarita namibiensis is closely related to Thioploca and Beggiatoa in function, their structures proved to be vastly different. Thioploca and Beggiatoa cells are much smaller and grow tightly stacked on each other in long filaments. Their shape is necessary for them to shuttle down into the ocean sediments to find more sulfide and nitrate. In contrast, Thiomargarita grow in rows of separate single ball shaped cells, not allowing them to have the range of mobility that Thioploca and Beggiota have. With their lack of movement they have adapted by evolving very large nitrate-storing bubbles, called vacuoles, allowing them to survive long periods of nitrate and sulfide starvation. The vacuoles give Thiomargarita the ability to stay immobile, just waiting for nitrate rich waters to sweep over them once again. These vacuoles are what account for the size that scientists had previously thought impossible. Scientists disregarded large bacterium because bacteria rely on diffusion to move chemicals around, a process that works only over tiny distances. This implies that the cytoplasm has to be close to the cell wall, greatly limiting their size. But Thiomargarita are an exception to this size constraint as their cytoplasms form along the peripheral cell membrane, while the nitrate-storing vacuoles occupy the cells of the Thiomargarita. As these vacuoles swell they greatly contribute to the record holding size. It holds the record for the world's largest bacteria with a volume three million times more than that of the average bacteria