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Deep Fe and microbes unknownAugust 3, 2012

Hello everyone!! Tomoyuki Hori from AIST present today’s report. In this cruise, I am trying to cultivate as-yet-unknown microbes living in the deep sediment. It has been unveiled that numerous microbial lives exist in the Shimokita subseafloor. However, little is known why these microbes can survive under the energy-limited environment. I hypothesize that the buried ferric iron minerals may be very important for the energy respiration. Iron is the fourth most abundant element in the earth’s crust, and in particular, the coast of Hachinohe and northern Honshu area in Japan has been famous for iron production (e.g., Japanese Samurai sword, temple ring). For instance, sand on the Tanesashi shore in Hachinohe city looks blackish, perhaps due to may iron like manganese. This shore has long history as a production area of good-quality iron sand in Japan. In this cruise, I look forward to seeing the 2 km-deep terrestrial deposit that may contain large amounts of iron. What is hidden relationship between deep life and iron minerals? I try to figure out this puzzle using new cultivation method with highly crystalline iron oxides as microbial energy sources. I am really waiting for the subsurface cores with great motivation.

Today, each research group perseveres in preparing experiments onboard. In parallel with this, "rig tour" was held, in which we visited the huge installation for core drilling such as the blow-out-preventer (BOP), riser pipes, and big engines. Many scientists, including me, are the first experience of Chikyu, so we enjoyed it very much. The picture was taken in so called “Driller’s House”, in which drillers control all the mechanical drilling process, seems one of the most special places in Chikyu. A smiled person on the seat for drillers is, actually, ME ! It was my precious experience in my life. We scientists thank ship crew very much for the kind guidance and their hard work. Expedition 337 is now ongoing by the big support of all ship crew. I appreciate them and do my best to achieve our scientific goals.

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