Vanadium is an element that is widely distributed in Earth's crust as well as in seawater and groundwater reservoirs. Therefore it exerts great influence on the issues related to life and the environment. Vanadium is utilized by several marine organisms. For example, there are vanadate-dependent haloperoxidases in algae and several bacteria (e.g. "Azotobacter") use it for nitrogen fixation and bacterial reduction involves the conversion of vanadate to oxide vanadium (IV).