Biodiversity / Food / Water

February 19, 2007


Coral Reef Restoration Efforts Underway in Waters off Ishigaki Island

Keywords: Ecosystems / Biodiversity Manufacturing industry Non-manufacturing industry University / Research institute 

Off the coast of Ishigaki, an island south of Okinawa, Japan, testing of an innovative method to accelerate coral regeneration was started as part of a full-scale coral transplant experiment, according to a September 2006 press release from Mitsubishi Heavy Industries Bridge & Steel Structures Engineering Co. (MBE). In collaboration with the University of Tokyo, Nippon Corrosion Engineering, Co. and C.P. Farm Co., a local expert in corals, MBE aims to establish the method by FY2008 and put it into practice in FY2009.

Prior to the experiment, MBE and C.P. Farm conducted small-scale transplantation of corals in October 2004, using floating piers as substrate. Over a one-year period, the coral fragments have increased in size by more than three times, although the survival rate of all transplanted corals was only 30 percent. To increase the survival rate, electrodeposition has been employed; low electric currents are fed into the substrate to induce mineral deposition on its surface, thereby providing a base for coral settlement.

In the experiment, wire mesh structures composed mainly of magnesium and iron materials are placed on the reef floor as coral substrate. The electricity is provided by a chemical reaction that constantly occurs and produces low voltage electricity around the structure. Unlike conventional electrodeposition, this generation system does not require external power sources (e.g., solar batteries) that are vulnerable to storm damage or nighttime power outages, and can thus provide a continuous power supply. The system is the first of its kind to be applied in this way.

During the experiment, MBE is responsible for fabricating and installing the substrates. Nippon Corrosion Engineering is responsible for the electrodeposition circuit, and C. P. Farm transplants the corals. The University of Tokyo is assigned to model simulations for tidal current changes and temperature distribution of the given waters, as well as analysis of coral growth.

Posted: 2007/02/19 10:50:47 AM
Japanese version