Zinc is an essential trace element for humans,[5][6][7] animals,[8] plants[9] and for microorganisms[10] and is necessary for prenatal and postnatal development.[11] It is the second most abundant trace metal in humans after iron and it is the only metal which appears in all enzyme classes.[9][7] Zinc is also an essential nutrient element for coral growth as it is an important cofactor for many enzymes.