A5054967948- Methane Hydrates and Related Phenomena
- Isotope Analysis in Ecology
- Hydrocarbon exploration and reservoir analysis
- Coral and Marine Ecosystems Studies
- Geology and Paleoclimatology Research
- Atmospheric and Environmental Gas Dynamics
- Microbial Community Ecology and Physiology
- Paleontology and Stratigraphy of Fossils
- Astro and Planetary Science
- Ocean Acidification Effects and Responses
- Planetary Science and Exploration
- Marine and coastal ecosystems
- Groundwater and Isotope Geochemistry
- Marine and fisheries research
- Marine Biology and Ecology Research
- Geochemistry and Elemental Analysis
- Marine and coastal plant biology
- Geological and Geochemical Analysis
- Marine Bivalve and Aquaculture Studies
- Oceanographic and Atmospheric Processes
- Genomics and Phylogenetic Studies
- Climate variability and models
- Geochemistry and Geologic Mapping
- Geological Studies and Exploration
- Geological and Geophysical Studies Worldwide
Japan Agency for Marine-Earth Science and Technology
2015-2024
Kyoto Prefectural University of Medicine
2022
University of Tsukuba
2021
The University of Tokyo
2019-2021
The Ohio State University
2010-2020
Sphere Institute
2020
Doshisha University
2018-2019
Tokyo Institute of Technology
2002-2008
Japan Science and Technology Agency
2007
Nagoya University
2001
The origin of eukaryotes remains unclear1–4. Current data suggest that may have emerged from an archaeal lineage known as 'Asgard' archaea5,6. Despite the eukaryote-like genomic features are found in these archaea, evolutionary transition archaea to unclear, owing lack cultured representatives and corresponding physiological insights. Here we report decade-long isolation Asgard archaeon related Lokiarchaeota deep marine sediment. archaeon—'Candidatus Prometheoarchaeum syntrophicum' strain...
Abstract Mass coral bleaching events caused by elevated seawater temperatures result in extensive loss throughout the tropics, and are projected to increase frequency severity. If becomes an annual event later this century, more than 90% of reefs worldwide may be at risk long‐term degradation. While corals can recover from single isolated acclimate recurring that separated multiple years, it is currently unknown if how they will survive possibly acclimatize bleaching. Here, we demonstrate...
Stable isotopes of water are important climatic tracers used to understand atmospheric moisture cycling and reconstruct paleoclimate. The combined use hydrogen oxygen in provides an additional parameter, deuterium excess ( d ), which might reflect ocean surface conditions source regions for precipitation. records from polar ice cores covering glacial‐interglacial cycles were temperatures at the source, enabling elimination effects conventional isotope thermometer. However, observations...
Rising atmospheric CO2 concentrations threaten coral reefs globally by causing ocean acidification (OA) and warming. Yet, the combined effects of elevated pCO2 temperature on physiology resilience remain poorly understood. While calcification energy reserves are important health indicators, no studies to date have measured reserve pools (i.e., lipid, protein, carbohydrate) together with under OA conditions different scenarios. Four species, Acropora millepora, Montipora monasteriata,...
Abstract Reliably predicting how coral calcification may respond to ocean acidification and warming depends on our understanding of mechanisms. However, the concentration speciation dissolved inorganic carbon (DIC) inside corals remain unclear, as only pH has been measured while a necessary second parameter constrain carbonate chemistry missing. Here we report first ion ([CO 3 2− ]) measurements together with during light period. We observe sharp increases in [CO ] from gastric cavity...
Abstract Hadal trench bottom (>6000 m below sea level) sediments harbor higher microbial cell abundance compared with adjacent abyssal plain sediments. This is supported by the accumulation of sedimentary organic matter (OM), facilitated topography. However, distribution benthic microbes in different systems has not been well explored yet. Here, we carried out small subunit ribosomal RNA gene tag sequencing for 92 sediment subsamples seven and hadal cores collected from three regions...
Mass bleaching events are predicted to occur annually later this century. Nevertheless, it remains unknown whether corals will be able recover between annual events. Using a combined tank and field experiment, we simulated by exposing three Caribbean coral species (Porites divaricata, Porites astreoides Orbicella faveolata) elevated temperatures for 2.5 weeks in 2 consecutive years. The impact of stress on chlorophyll a, energy reserves, calcification, tissue C N isotopes was assessed...
Abstract The origin of eukaryotes remains enigmatic. Current data suggests that may have risen from an archaeal lineage known as “Asgard archaea”. Despite the eukaryote-like genomic features found in these archaea, evolutionary transition archaea to unclear due lack cultured representatives and corresponding physiological insight. Here we report decade-long isolation a Lokiarchaeota-related Asgard archaeon deep marine sediment. archaeon, “ Candidatus Prometheoarchaeum syntrophicum strain...
The near-Earth carbonaceous asteroid (162173) Ryugu is expected to contain volatile chemical species that could provide information on the origin of Earth's volatiles. Samples were retrieved by Hayabusa2 spacecraft. We measured noble gas and nitrogen isotopes in samples found they are dominated presolar primordial components, incorporated during Solar System formation. Noble concentrations higher than those Ivuna-type (CI) chondrite meteorites. Several host phases isotopically distinct have...
Mounding corals survive bleaching events in greater numbers than branching corals. However, no study to date has determined the underlying physiological and biogeochemical trait(s) that are responsible for mounding coral holobiont resilience bleaching. Furthermore, potential of dissolved organic carbon (DOC) as a source fixed bleached never been determined. Here, Porites lobata were experimentally 23 days then allowed recover 0, 1, 5, 11 months. At each recovery interval suite analyses...
The physiological response to individual and combined stressors of elevated temperature pCO2 were measured over a 24-day period in four Pacific corals their respective symbionts (Acropora millepora/Symbiodinium C21a, Pocillopora damicornis/Symbiodinium C1c-d-t, Montipora monasteriata/Symbiodinium C15, Turbinaria reniformis/Symbiodinium trenchii). Multivariate analyses indicated that played greater role altering response, with the greatest degree change occurring within M. monasteriata T....
Hydrogen and carbon isotope systematics of H2O–H2–CO2–CH4 in hydrogenotrophic methanogenesis their relation to H2 availability were investigated. Two H2-syntrophic cocultures fermentatively hydrogenogenic bacteria methanogens under conditions <102 Pa-H2 two pure cultures ~105 tested. Carbon fractionation between CH4 CO2 during was correlated with pH2, as indicated previous studies. The hydrogen ratio produced rapid growth the thermophilic methanogen Methanothermococcus okinawensis high pH2...
We measured the intramolecular distribution of 15 N as well conventional nitrogen and oxygen isotope ratios in oceanic nitrous oxide (N 2 O) western North Pacific for first time. In contrast to a nearly homogeneous vertical bulk ratio, wide variation site preference was found, suggesting subsurface deep source mixing production mechanism ocean. The composition O isotopomers quantitatively outlines ocean most significant after terrestrial one.
Since the initial discovery of hydrothermal vents in 1977, these ‘extreme’ chemosynthetic systems have been a focus interdisciplinary research. The Okinawa Trough (OT), located semi-enclosed East China Sea between Eurasian continent and Ryukyu arc, hosts more than 20 known vent sites but all within relatively narrow depth range (600–1880 m). Depth is significant factor determining fluid temperature chemistry, as well biological composition. However, due to sites, actual influence here has...
This paper describes a method to survey the distribution of megabenthos over multi-hectare regions seafloor. Quantitative biomass estimates are made by combining high-resolution 3D image reconstructions, used model spatial relationships between representative taxa, with lower-resolution reconstructions taken wider area in which larger predatory animals can be observed. The is applied region Iheya North field that was target scientific drilling during IODP Expedition 331 2010. An 2.5 ha...
Abstract Seafloor massive sulphide (SMS) deposits, modern analogues of volcanogenic (VMS) deposits on land, represent future resources base and precious metals. Studies VMS have proposed two emplacement mechanisms for SMS deposits: exhalative deposition the seafloor mineral void space replacement beneath seafloor. The details latter mechanism are poorly characterised in detail, despite its potentially significant role global metal cycling throughout Earth’s history, because in-situ studies...
The Hayabusa2 spacecraft returned to Earth from the asteroid 162173 Ryugu on 6 December 2020. One day after recovery, gas species retained in sample container were extracted and measured on-site stored collection bottles. consists of helium neon with an extraterrestrial 3 He/ 4 He 20 Ne/ 22 Ne ratios, along some contaminant terrestrial atmospheric gases. A mixture solar Earth’s is best explanation for composition. Fragmentation grains within discussed basis estimated amount indigenous size...
Carbonaceous chondrites are considered to have originated from C-type asteroids and represent some of the most primitive material in our solar system. Furthermore, since carbonaceous can contain significant quantities volatile elements, they may played a crucial role supplying volatiles organic Earth other inner system bodies. However, major challenge unravelling composition chondritic meteorites is distinguishing between which features were inherited parent body, what be secondary feature...
Abstract. Full-depth profiles of hydrographic and geochemical properties at the Izu–Ogasawara Trench were observed for first time using a CTD-CMS (conductivity–temperature–depth profiler with carousel multiple sampling) system. Additionally, comparative samplings done northern Mariana same methods. A well-mixed structure below 7000 m was within Trench. Seawater samples collected from this hadal layer exhibited constant concentrations nitrate, phosphate, silicate, nitrous oxide as well...
Deep-sea geofluid systems, such as hydrothermal vents and cold seeps, are key to understanding subseafloor environments of Earth. Fluid chemistry, especially, provides crucial information towards elucidating the physical, chemical biological processes that occur in these ecosystems. To accurately assess fluid gas properties deep-sea geofluids, well-designed pressure-tight samplers indispensable they important assets research. Here, development a new flow-through, sampler capable four...