scholarly journals Stress history in the forearc region of the Nankai trough subduction zone: paleostress analysis based on faults in core samples from the Kumano Ichiura and Kihoku Miyama sites, Kii Peninsula, SW Japan

2009 ◽  
Vol 115 (9) ◽  
pp. 457-469 ◽  
Author(s):  
Makoto Otsubo ◽  
Norio Shigematsu ◽  
Yuichi Kitagawa ◽  
Naoji Koizumi
Keyword(s):  
Subduction Zone ◽  
Nankai Trough ◽  
Stress History ◽  
Kii Peninsula ◽  
Core Samples ◽  
Paleostress Analysis ◽  
Forearc Region ◽  
Sw Japan

scholarly journals Distribution of dehalogenation activity in subseafloor sediments of the Nankai Trough subduction zone

2013 ◽  
Vol 368 (1616) ◽  
pp. 20120249 ◽  
Author(s):  
Taiki Futagami ◽  
Yuki Morono ◽  
Takeshi Terada ◽  
Anna H. Kaksonen ◽  
Fumio Inagaki
Keyword(s):  
Subduction Zone ◽  
Nankai Trough ◽  
Anaerobic Respiration ◽  
Northwest Pacific ◽  
Kii Peninsula ◽  
Expression Screening ◽  
Reductive Dehalogenase ◽  
Enrichment Cultures ◽  
Incubation Experiments ◽  
Plate Subduction

Halogenated organic matter buried in marine subsurface sediment may serve as a source of electron acceptors for anaerobic respiration of subseafloor microbes. Detection of a diverse array of reductive dehalogenase-homologous ( rdhA ) genes suggests that subseafloor organohalide-respiring microbial communities may play significant ecological roles in the biogeochemical carbon and halogen cycle in the subseafloor biosphere. We report here the spatial distribution of dehalogenation activity in the Nankai Trough plate-subduction zone of the northwest Pacific off the Kii Peninsula of Japan. Incubation experiments with slurries of sediment collected at various depths and locations showed that degradation of several organohalides tested only occurred in the shallow sedimentary basin, down to 4.7 metres below the seafloor, despite detection of rdhA in the deeper sediments. We studied the phylogenetic diversity of the metabolically active microbes in positive enrichment cultures by extracting RNA, and found that Desulfuromonadales bacteria predominate. In addition, for the isolation of genes involved in the dehalogenation reaction, we performed a substrate-induced gene expression screening on DNA extracted from the enrichment cultures. Diverse DNA fragments were obtained and some of them showed best BLAST hit to known organohalide respirers such as Dehalococcoides , whereas no functionally known dehalogenation-related genes such as rdhA were found, indicating the need to improve the molecular approach to assess functional genes for organohalide respiration.

Imaging of the subducted Kyushu-Palau Ridge in the Hyuga-nada region, western Nankai Trough subduction zone

2013 ◽  
Vol 589 ◽  
pp. 90-102 ◽  
Author(s):  
Yojiro Yamamoto ◽  
Koichiro Obana ◽  
Tsutomu Takahashi ◽  
Ayako Nakanishi ◽  
Shuichi Kodaira ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Nankai Trough

scholarly journals Heat flow distribution and thermal structure of the Nankai subduction zone off the Kii Peninsula

2011 ◽  
Vol 12 (10) ◽  
pp. n/a-n/a ◽  
Author(s):  
Hideki Hamamoto ◽  
Makoto Yamano ◽  
Shusaku Goto ◽  
Masataka Kinoshita ◽  
Keiko Fujino ◽  
...  
Keyword(s):  
Heat Flow ◽  
Subduction Zone ◽  
Thermal Structure ◽  
Flow Distribution ◽  
Kii Peninsula ◽  
Nankai Subduction Zone

scholarly journals Temperature limits to deep subseafloor life in the Nankai Trough subduction zone

Science ◽  
2020 ◽  
Vol 370 (6521) ◽  
pp. 1230-1234
Author(s):  
Verena B. Heuer ◽  
Fumio Inagaki ◽  
Yuki Morono ◽  
Yusuke Kubo ◽  
Arthur J. Spivack ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Marine Sediment ◽  
Nankai Trough ◽  
Microbial Populations ◽  
Vegetative Cells ◽  
Microbial Life ◽  
Sediment Volume ◽  
Subsurface Sediments ◽  
Cell Concentrations ◽  
Deep Subseafloor

Microorganisms in marine subsurface sediments substantially contribute to global biomass. Sediments warmer than 40°C account for roughly half the marine sediment volume, but the processes mediated by microbial populations in these hard-to-access environments are poorly understood. We investigated microbial life in up to 1.2-kilometer-deep and up to 120°C hot sediments in the Nankai Trough subduction zone. Above 45°C, concentrations of vegetative cells drop two orders of magnitude and endospores become more than 6000 times more abundant than vegetative cells. Methane is biologically produced and oxidized until sediments reach 80° to 85°C. In 100° to 120°C sediments, isotopic evidence and increased cell concentrations demonstrate the activity of acetate-degrading hyperthermophiles. Above 45°C, populated zones alternate with zones up to 192 meters thick where microbes were undetectable.

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