Carbonates are most often formed as biogenic or chemical sediments in marine environments. This may also encompass alkaloids, terpenes, polysaccharides, biogenic amines, and organic acids. Air pollution has two primary sources, biogenic and anthropogenic. However, food containing high amounts of biogenic amines may have toxicological effects. Unusually, diatoms have a cell wall composed of biogenic silica. This receptor is activated by the biogenic amine histamine. The endocarp contains significant amounts of biogenic carbonate that is nearly pure aragonite. It is called biogenic sulfide corrosion. Consisting of mostly methane, natural gas is produced using two methods&colon; biogenic and thermogenic. As an alternative, several researchers have investigated the precipitation of metals using biogenic sulfide. As a volcanic and biogenic species, methane is of interest to many geologists and astrobiologists. The Spratly Islands consist of islands, reefs, banks and shoals that consist of biogenic carbonate. About 30% of people are sensitive to biogenic amines, such as histamines. These chemical compounds can be best explained as residues of biogenic organic matter. Detection of microbial life on Titan would depend on its biogenic effects.