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Oyamada K.,Jfe Holdings | Okamoto M.,Tokyo University of Marine Science and Technology | Iwata I.,Fuyo Ocean Development and Engineering
JFE Technical Report | Year: 2014

JFE Steel has developed restoration technology of damaged coral reefs using carbonated block, "Marine BlockTM." In Miyakojima in Okinawa Prefecture, the transplanted larva coral on "Marine BlockTM" had spawned eggs, and it was proved that this technology is well suited to coral reef restoration. Furthermore, this technology is currently on-site evaluation in the Republic of Indonesia, and the progress of this experimental project will be introduced in this paper. Source


Utsunomiya T.,Kyoto University | Shiraishi T.,Hitachi Ltd. | Sato I.,Toda Corporation | Inui E.,Fuyo Ocean Development and Engineering | Ishida S.,Japan National Maritime Research Institute
OCEANS 2014 - TAIPEI | Year: 2014

Offshore wind energy resources in Japanese EEZ (Exclusive Economic Zone) are now considered to be huge. In order to utilize the huge amount of energy located in relatively deep water areas, Ministry of the Environment, Japan has kicked-off the demonstration project on floating offshore wind turbine (FOWT). The project will continue for six years beginning from 2010fy to 2015fy. In the project, two FOWTs have been installed. The first FOWT mounts a 100kW wind turbine of downwind type, and the length dimensions are almost half of the second FOWT (so called as 1/2 scale model). The second FOWT mounts a 2MW wind turbine of downwind type, and called as a full scale model. The FOWTs consist of PC-steel hybrid spar (which is cost-effective) and are moored by three mooring chains. The half scale model was installed at the site on 11 June 2012 as the first grid-connected FOWT in Japan. The half scale model was attacked by very severe typhoon Sanba (1216), the greatest tropical typhoon in 2012 in the world. The behavior during the typhoon attack, including the measured environmental data and the FOWT responses is introduced. The installation of the full scale model has also successfully been made. The installation at the site completed on 18 October 2013; as the first multi-megawatt FOWT in Japan. The installation procedures and current status are also presented. © 2014 IEEE. Source


Yoshikawa S.,Japan Agency for Marine - Earth Science and Technology | Kanamatsu T.,Japan Agency for Marine - Earth Science and Technology | Goto K.,Tohoku University | Sakamoto I.,Tokai University | And 5 more authors.
Geo-Marine Letters | Year: 2015

Ongoing geological research into processes operating on the nearshore continental shelf and beyond is vital to our understanding of modern tsunami-generated sediment transport and deposition. This paper investigates the southern part of Sendai Bay, Japan, by means of high-resolution seismic surveys, vibracoring, bathymetric data assimilation, and radioisotope analysis of a core. For the first time, it was possible to identify an erosional surface in the shallow subsurface, formed by both seafloor erosion and associated offshore-directed sediment transport caused by the 2011 Tohoku-oki tsunami. The area of erosion and deposition extends at least 1,100 m offshore from the shoreline down to water depths of 16.7 m. The tsunami-generated sedimentological signature reaches up to 1.2 m below the present seafloor, whereas bathymetric changes due to storm-related reworking over a period of 3 years following the tsunami event have been limited to the upper ~0.3 m, despite the fact that the study area is located on an open shelf facing the Pacific Ocean. Tsunami-generated erosion surfaces may thus be preserved for extended periods of time, and may even enter the rock record, because the depth of tsunami erosion can exceed the depth of storm erosion. This finding is also important for interpretation of modern submarine strata, since erosion surfaces in shallow (depths less than ~1 m) seismic records from open coast shelves have generally been interpreted as storm-generated surfaces or transgressive ravinement surfaces. © 2015, Springer-Verlag Berlin Heidelberg. Source


Okamoto M.,Tokyo University of Marine Science and Technology | Yap M.,Tokyo University of Marine Science and Technology | Roeroe A.K.,Sam Ratulangi University | Nojima S.,Kyushu University | And 3 more authors.
Fisheries Science | Year: 2010

The growth of Acropora in Sekisei Lagoon was investigated in situ using ceramic coral settlement devices (CSDs) and marine blocks (MBs) with small holes on their surfaces that were deployed prior to a mass spawning event. Acropora that had settled in 10-mm holes on the upper surface of the MBs were found to have grown inwards after 348 days post-mass spawning. After 733 days, the colonies had grown outwards, encrusting the blocks and attaining a maximum diameter of 21.5 mm (3.7 mm). CSDs that had been stacked above each other on frames were separated and observed in situ on 405 and 764 days after mass spawning. After 405 days, the maximum diameter of the encrusting Acropora was 7.6 mm (±2.4 mm), which increased to 19.4 mm (±5.5 mm) after 764 days, with 30% of colonies extending short branches. The length of the branches of Acropora grown on the CSDs fixed to the MBs 3 months after the mass spawning event exceeded the size of the encrusting portion of the colony 629 days after spawning. The mortality of colonies between 1 and 2 years was slight, with the temperatures conducive to coral bleaching that occurred during the study also having only a slight effect. © The Japanese Society of Fisheries Science 2010. Source


Tian K.,Tokyo University of Marine Science and Technology | Okamoto M.,Tokyo University of Marine Science and Technology | Kamoshita S.,Forestry and Fisheries | Iwata I.,Fuyo Ocean Development and Engineering
Mer | Year: 2013

We developed seedling cultivation methods for transplantation of young Eisenia bicyclis and Ecklonia cava plants using settlement devices (SDs). Experiments were conducted using four settlement devices consisting of (1) flat unglazed china, (2) unglazed china with small hollows, (3) two (06 and 07) slag-ceramic interfaces with minute (3-10 μm diameter) pores. No seaweeds grew on the flat unglazed china in a seawater circulation tank on land after release of E. bicyclis zoospores. Hollow china and 06 slag-ceramic SDs were deployed at depths of 0 m, 0.2 m, and 2 m in a forest of E. bicyclis for 6 months. The sun-illuminated sides of SDs were fully covered by small seaweeds (excluding Eisenia) depending on the depth (Ulva at a depth of 0 m, Chondrus at 0.2 m, and Chondrus and Gelidium at 2 m). However, attachment of Ulva on the two types of SDs was different. Viva could be easily removed from the hollowed surface, but it could not be separated from the surface of the slag-ceramic SDs even with a knife. On the 07 slag-ceramic SDs placed in a seawater tank, E. bicyclis could be raised from the settled zoospores released from their mother plants. Hundred days after settlement, 17-18 sporophyte Eisenia (2-4 cm) grew on 1 slag-ceramic SD. It was possible for slag-ceramic SD to brush not damaging E. bicyclis on the SD. Source

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