NANKOKU, Kochi -- A team at the Japan Agency for Marine-Earth Science and Technology Kochi Institute for Core Sample Research is conducting a study to mitigate the size of tsunami like that of the 2011 disaster using bacteria, it has been learned.
The research team hopes to utilize bacteria to anchor the oceanic and continental tectonic plates at their boundaries in shallow areas so that the size of a given shift is smaller each time, thus reducing the size of the tsunami. The idea has been labeled "outrageous," and the realization of the technique is still far down the road, but the researchers are serious about the potential of the plan.
A tsunami occurs when underwater tectonic plates make a large shift in their position where they move against each other. The Kochi research team, including Yohei Hamada, first considered injecting a cement-like substance to fix the plate boundaries together, but ran into difficulties getting the substance to spread out effectively due to its stickiness. That's where the bacteria came in.
Carbonate ions secreted by certain types of bacteria can react with the calcium in sea water to form calcium carbonate, a cement-like replacement to create friction. A bacteria culture is slippery and can easily get into the spaces between the plates, and the bacteria themselves are self-reproducing, so they multiply and spread out easily. Out of four types of bacteria tested, the team found that "Sporosarcina ureae" produced the largest amount of calcium carbonate.
In experiments carried out using a friction and abrasion testing machine that replicated conditions at plate boundaries, the use of Sporosarcina ureae increased the amount of friction by roughly 10 percent. With these promising results, it is possible to see a way for the bacteria to limit how much the plates move at once and reduce the size of the tsunami the shift creates.
There are still many challenges facing the research team, such as how to inject the bacteria into the plate boundary. "We are still far from the practical application of our findings, but research into increasing the strength of the calcium carbonate rock is progressing," Hamada said.