PROBLEM TO BE SOLVED: To provide an artificial material for supplying minerals to preserve an aquatic environment, which can supply minerals such as silicon and iron to an aquatic area where minerals needed for animals and plants in the aquatic area such as the coasts, water surfaces or water bottoms of fresh water, brackish water or sea water have been shortened to reduce or eliminate the colonies of algae, water plants or sea plants, and can promote the growths of the algae, the water plants or the sea plants and the reproduction of fishes or shellfishes, thus enabling to improve the reduced or eliminated seaweed beds and fishing banks.SOLUTION: The artificial material for supplying minerals to preserve the aquatic environment and the method for preserving the aquatic environment, using the material, comprise: to receive the material for applying to the aquatic area lacking minerals essential for the growths of animals or plants, which is a mixture adjusted so that the pH of the mixture of an ion exchange substance with a mineral-containing substance including a carbonated iron-steel slag is &le；8.5, in a water-permeable package； and to set the package to the aquatic area.
