The top clinometer is a newly developed payload tool which enables a submersible vehicle to directly measure orientation of planar geological structures (e.g. bedding planes, faults) on seafloor outcrops. It consists of a disc and central vertical bar, both graduated at 1 cm scales, and a handle. On seafloor outcrops, the disc is placed on the geological surface of interest by a manipulator, and is captured by a still camera. The orientations are determined via simple onboard graphic analyses of the images obtained and the submersible log data. Strike and dip of the surface structures are routinely calculated by a macro program within a Microsoft Excel worksheet. Theoretical and laboratory tests suggest errors of the measurements in the same order as magnetic clinometer compasses commonly used for on-land geological surveys. Camera installation angles to the submersible Shinkai 6500 were also calibrated based on on-deck tests during R/V Yokosuka YK08-05 and YK10-13 Leg2 cruises. Results of three practical measurements suggested that speed of the operation depends heavily on the time spent looking for the target surfaces and the time for communication between operators and scientists. Besides these factors, a measurement can be taken in as little as five minutes. This simple and quick method improves the quality of structural measurements for submarine geology.

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Seawater sampling was conducted by a CTD system attached with Niskin-X sampler in the R/V Mirai. Niskin-X sampler can eliminate the contamination of toxic rubber and trace metal in the bottle as much as possible, because its closure spring is arranged outside of the bottle. Teflon-coated and acid-cleaned samplers of them were usually used for the sampling of primary production as “clean” Niskin. We tested the difference of primary production between “clean” and other “normal” Niskin sampling. Primary production estimated from “normal” Niskin sampling was decreased drastically than “clean” Niskin sampling. We tested again to evaluate the cause of such difference, and it was revealed that the using of nitrile rubber O-rings in the “normal” Niskin sampler inhibited primary production.

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During the interval from 4.9 to 4.1-3.7 Ma in the early Pliocene, extinct fossil freshwater diatom species Aulacoseira praeislandica and near-shore marine fossil diatom species Koizumia tatsunokuchiensis are abundant at DSDP Site 436 on the abyssal floor far east over the Japan Trench as sediment trap. The close correspondence of abundances of two characteristic diatom groups with occurrence of coarse volcanic debris, increase of eolian material, and large numbers of fecal pellets in the early Pliocene sediment at Site 436 suggests deposition by the settled water column after being transported to the area through the Kuroshio-Kuroshio Extension system driven by winds and the atmosphere by the typhoons during a warming climate interval. The early Pliocene is considered to be the warmest interval and a period of reduced latitudinal thermal gradients. Tropical cyclones (hurricanes and typhoons) and ocean wind-driven circulations are simulated by modeling studies to have increased during the early Pliocene because of a vast pole-ward expansion of the tropical warm pool that associated with expanded El Niño-like conditions. And the Pliocene coral records support that stronger winds in the tropical Pacific act as a possible driving force of the western Pacific warm pool. Tropical storms in the early Pliocene increased ocean vertical mixing and transported heat pole-wards. Atmosphere-ocean circulations are considered as efficient media for the upwelling and transportation. The Pliocene extinct freshwater and near-shore marine diatoms at Site 436 may have been derived from the continent or/and sea bottom by atmosphere-ocean dynamics along frontal boundaries moved northward off Japan during the warm early Pliocene.

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KAIKO 7000 II is a Remotely Operated Vehicle (ROV) which can dive 7,000 meters under the sea. KAIKO 7000 II is composed of launcher and vehicle part. The Research Vessel KAIREI and the launcher are connected by primary cable, and the launcher and the vehicle are connected by secondary cable. By existing composition, single mode optical fiber (SM fiber) is adapted to primary cable, and graded index optical fiber (GI fiber) is adapted to secondary cable. Recently, the transmission quantity of GI fiber is not enough for high density data like HDTV to be transmitted. So, it is desired that the new secondary cable which adopted SM fiber is exchanged. From 2009, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) started to exchange to new secondary cable which adopted SM fiber, and, in February 2011, succeeded communication test under the sea. By adopting the single mode, the capacity of transmission glows and large capacity data like HDTV can be transmitted. In this report, the author shows details of optical transmit telemetry, and the result of engineering test under water.

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