Yutaro Takaya
Japan Agency for Marine-Earth Science and Technology
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Featured researches published by Yutaro Takaya.
PLOS ONE | 2015
Ryota Nakajima; Hiroyuki Yamamoto; Shinsuke Kawagucci; Yutaro Takaya; Tatsuo Nozaki; Chong Chen; Katsunori Fujikura; Tetsuya Miwa; Ken Takai
There has been an increasing interest in seafloor exploitation such as mineral mining in deep-sea hydrothermal fields, but the environmental impact of anthropogenic disturbance to the seafloor is poorly known. In this study, the effect of such anthropogenic disturbance by scientific drilling operations (IODP Expedition 331) on seabed landscape and megafaunal habitation was surveyed for over 3 years using remotely operated vehicle video observation in a deep-sea hydrothermal field, the Iheya North field, in the Okinawa Trough. We focused on observations from a particular drilling site (Site C0014) where the most dynamic change of landscape and megafaunal habitation was observed among the drilling sites of IODP Exp. 331. No visible hydrothermal fluid discharge had been observed at the sedimentary seafloor at Site C0014, where Calyptogena clam colonies were known for more than 10 years, before the drilling event. After drilling commenced, the original Calyptogena colonies were completely buried by the drilling deposits. Several months after the drilling, diffusing high-temperature hydrothermal fluid began to discharge from the sedimentary subseafloor in the area of over 20 m from the drill holes, ‘artificially’ creating a new hydrothermal vent habitat. Widespread microbial mats developed on the seafloor with the diffusing hydrothermal fluids and the galatheid crab Shinkaia crosnieri endemic to vents dominated the new vent community. The previously soft, sedimentary seafloor was hardened probably due to barite/gypsum mineralization or silicification, becoming rough and undulated with many fissures after the drilling operation. Although the effects of the drilling operation on seabed landscape and megafaunal composition are probably confined to an area of maximally 30 m from the drill holes, the newly established hydrothermal vent ecosystem has already lasted 2 years and is like to continue to exist until the fluid discharge ceases and thus the ecosystem in the area has been altered for long-term.
Handbook on The Physics and Chemistry of Rare Earths | 2015
Kentaro Nakamura; Koichiro Fujinaga; Kazutaka Yasukawa; Yutaro Takaya; Junichiro Ohta; Shiki Machida; Satoru Haraguchi; Yasuhiro Kato
Abstract This chapter focuses on newly discovered extensive deposits of deep-sea mud containing high concentrations of rare-earth elements and yttrium (REY). The deep-sea REY-rich muds are found in pelagic region of the Pacific Ocean and very recently also in the Indian Ocean. REY-rich muds are characterized by the following five advantages: (1) tremendous resource potential by virtue of their wide distribution, (2) high REY concentrations with significant heavy REE enrichment, (3) a stratiform distribution that allows relatively simple and cost-effective exploration, (4) very low concentrations of radioactive elements such as Th and U, and (5) ease of extraction of REY by acid leaching. These features demonstrate that the REY-rich mud could constitute a highly promising REY resource for the future. A system to mine REY-rich muds is also presented. This system can be developed based on a system developed and tested for sulfide-rich muds in the Red Sea and manganese nodules in the Pacific Ocean, although pressurized air-lift system will be needed to lift REY-rich muds from very deep water.
Scientific Reports | 2018
Yutaro Takaya; Kazutaka Yasukawa; Takehiro Kawasaki; Koichiro Fujinaga; Junichiro Ohta; Yoichi Usui; Kentaro Nakamura; Jun-Ichi Kimura; Qing Chang; Morihisa Hamada; Gjergj Dodbiba; Tatsuo Nozaki; Koichi Iijima; Tomohiro Morisawa; Takuma Kuwahara; Yasuyuki Ishida; Takao Ichimura; Masaki Kitazume; Toyohisa Fujita; Yasuhiro Kato
Potential risks of supply shortages for critical metals including rare-earth elements and yttrium (REY) have spurred great interest in commercial mining of deep-sea mineral resources. Deep-sea mud containing over 5,000 ppm total REY content was discovered in the western North Pacific Ocean near Minamitorishima Island, Japan, in 2013. This REY-rich mud has great potential as a rare-earth metal resource because of the enormous amount available and its advantageous mineralogical features. Here, we estimated the resource amount in REY-rich mud with Geographical Information System software and established a mineral processing procedure to greatly enhance its economic value. The resource amount was estimated to be 1.2 Mt of rare-earth oxide for the most promising area (105 km2 × 0–10 mbsf), which accounts for 62, 47, 32, and 56 years of annual global demand for Y, Eu, Tb, and Dy, respectively. Moreover, using a hydrocyclone separator enabled us to recover selectively biogenic calcium phosphate grains, which have high REY content (up to 22,000 ppm) and constitute the coarser domain in the grain-size distribution. The enormous resource amount and the effectiveness of the mineral processing are strong indicators that this new REY resource could be exploited in the near future.
Nature Geoscience | 2011
Yasuhiro Kato; Koichiro Fujinaga; Kentaro Nakamura; Yutaro Takaya; Kenichi Kitamura; Junichiro Ohta; Ryuichi Toda; Takuya Nakashima; Hikaru Iwamori
Geochimica et Cosmochimica Acta | 2014
Kosuke T. Goto; Ariel D. Anbar; Gwyneth W. Gordon; Stephen J. Romaniello; Gen Shimoda; Yutaro Takaya; Ayaka Tokumaru; Tatsuo Nozaki; Katsuhiko Suzuki; Shiki Machida; Takeshi Hanyu; Akira Usui
Geochemistry Geophysics Geosystems | 2013
Shinsuke Kawagucci; Junichi Miyazaki; Ryota Nakajima; Tatsuo Nozaki; Yutaro Takaya; Yasuhiro Kato; Takazo Shibuya; Uta Konno; Yuzuru Nakaguchi; Kenta Hatada; Hisako Hirayama; Katsunori Fujikura; Yasuo Furushima; Hiroyuki Yamamoto; Tomo-o Watsuji; Jun-ichiro Ishibashi; Ken Takai
Geochemical Journal | 2016
Koichi Iijima; Kazutaka Yasukawa; Koichiro Fujinaga; Kentaro Nakamura; Shiki Machida; Yutaro Takaya; Junichiro Ohta; Satoru Haraguchi; Yoshiro Nishio; Yoichi Usui; Tatsuo Nozaki; Toshitsugu Yamazaki; Yuji Ichiyama; Akira Ijiri; Fumio Inagaki; Hideaki Machiyama; Katsuhiko Suzuki; Yasuhiro Kato
Geochemical Journal | 2015
Ayaka Tokumaru; Tatsuo Nozaki; Katsuhiko Suzuki; Kosuke T. Goto; Qing Chang; Jun-Ichi Kimura; Yutaro Takaya; Yasuhiro Kato; Akira Usui; Tetsuro Urabe
Geochemical Journal | 2016
Koichiro Fujinaga; Kazutaka Yasukawa; Kentaro Nakamura; Shiki Machida; Yutaro Takaya; Junichiro Ohta; Shuhei Araki; Hanjie Liu; Ryo Usami; Ryota Maki; Satoru Haraguchi; Yoshiro Nishio; Yoichi Usui; Tatsuo Nozaki; Toshitsugu Yamazaki; Yuji Ichiyama; Akira Ijiri; Fumio Inagaki; Hideaki Machiyama; Koichi Iijima; Katsuhiko Suzuki; Yasuhiro Kato; E Leg Kr; Kr Cruise Members
Lithos | 2014
Kazue Suzuki; Shinji Yamamoto; Yusuke Sawaki; Kazumasa Aoki; Soichi Omori; Yoshiaki Kon; Takafumi Hirata; Yibing Li; Yutaro Takaya; Koichiro Fujinaga; Yasuhiro Kato; Shigenori Maruyama