Abstract: The present invention provides a movable breakwater that can do with a small amount of compressed air supplied to raise the buoyant steel pipe. The buoyant steel pipe 6 includes a buoyancy tank 6d in which gas is filled, an air chamber 6e provided above the buoyancy tank 6d, a penetration pipe 19 that penetrates through the buoyancy tank 6d and feeds compressed air supplied from a pressure accumulator tank 13 to the air chamber 6e, and an open chamber 6f, whose top side is open, provided above the air chamber 6e and in the buoyant steel pipe 6 at the upper end portion thereof.

Abstract: A coral cultivation method includes: an electrodeposited-mineral precipitating procedure for precipitating electrodeposited minerals on a coral-growth substrate for growing coral, which is placed in seawater, by applying an electric current between the coral-growth substrate and a first anode that is electrically connected to the coral-growth substrate and placed in the seawater; a coral-larvae growing procedure for growing coral larvae on the coral-growth substrate precipitated with the electrodeposited minerals; a coral-cultivation-structure configuring procedure for configuring a coral cultivation structure from a plurality of the coral-growth substrates on which the coral larvae are grown; and a coral cultivating procedure for cultivating coral by applying an electric current between the coral-growth substrate on which the coral larvae are grown and a second anode.

Abstract: A coral cultivation method includes: an electrodeposited-mineral precipitating procedure for precipitating electrodeposited minerals on a coral-growth substrate for growing coral, which is placed in seawater, by applying an electric current between the coral-growth substrate and a first anode that is electrically connected to the coral-growth substrate and placed in the seawater; a coral-larvae growing procedure for growing coral larvae on the coral-growth substrate precipitated with the electrodeposited minerals; a coral-cultivation-structure configuring procedure for configuring a coral cultivation structure from a plurality of the coral-growth substrates on which the coral larvae are grown; and a coral cultivating procedure for cultivating coral by applying an electric current between the coral-growth substrate on which the coral larvae are grown and a second anode.