Red blood cell thus much more common than the other blood particles: there are about 4,000–11,000 white blood cells and about 150,000–400,000 platelets per microliter. Human red blood cells take on average 60 seconds to complete one cycle of circulation. The blood's red color is due to the spectral properties of the hemic iron ions in hemoglobin. Each human red blood cell contains approximately 270 million of these hemoglobin molecules. Each hemoglobin molecule carries four heme groups; hemoglobin constitutes about a third of the total cell volume. Hemoglobin is responsible for the transport of more than 98% of the oxygen in the body
Oxygen minimum zone to either make do with lesser amounts of oxygen or to extract oxygen from the water more efficiently. For example, the giant red mysid ("Gnathophausia ingens") continues to live aerobically (using oxygen) in OMZs. They have highly developed gills with large surface area and thin blood-to-water diffusion distance that enables effective removal of oxygen from the water (up to 90% O removal from inhaled water) and an efficient circulatory system with high capacity and high blood concentration of a protein (hemocyanin) that readily binds oxygen. Another strategy used by some classes of bacteria in the oxygen minimum zones is to