Despite the apparent uniformity and homogeneity of the water masses in the sea, there are areas similar to terrestrial biogeochemical provinces. Abnormalities or deviations from the background in the environment and biota stipulated by the geochemical features of these zones are not as pronounced as in the sea. They appear not only in the existence of endemic diseases caused by changes in the mineral metabolism of terrestrial organisms but also in distinctive biocenoses and mineral compositions of organisms. In the sea, the difference between the concentrations of elements in a biogeochemical province and beyond it may not be as sharp as on land because of the nature of the environment.