@article {1976,
	title = {Foraminiferal isotope anomalies from northwestern Pacific marginal sediments},
	journal = {Geochemistry Geophysics Geosystems},
	volume = {6},
	year = {2005},
	note = {917qmTimes Cited:9
Cited References Count:48
},
	month = {Apr 12},
	pages = {1525-2027},
	abstract = {[1] We evaluated the influence of methane release from methane hydrate reservoirs in the northwestern Pacific continental margin on stable isotope values. We analyzed stable isotopes of foraminifera from a piston core collected at 1066-m water depth off eastern Hokkaido, northern Japan. Carbon isotope signals indicated that planktonic and benthic foraminifera in several glacial sediment layers in the core were highly depleted in C-13; both the planktonic and benthic foraminiferal delta C-13 values ranged from about -10 parts per thousand to -2 parts per thousand. Most foraminiferal tests in these horizons were brown as a result of postdepositional alteration. Foraminiferal oxygen isotopes fluctuated abnormally in the glacial sediment layers, showing small ( about 0.5 parts per thousand) positive shifts relative to normal glacial values. We attributed the positive shifts to authigenic carbonate formation in the foraminiferal tests. The authigenic carbonates have formed when rising methane, from methane hydrate in the sediment, became oxidized as it came in contact with dissolved sulfate near the seafloor. Episodic methane-release events may be associated with great plate-boundary earthquakes with epicenters near the coring site.},
	keywords = {atmospheric processes : paleoclimatology, benthic foraminifera, California, carbon isotopes, corals, Foraminifera, gas-hydrate, kuril trench, marine geology and geophysics : marine sediments : processes and transport, methane hydrate, methane release, northwestern pacific ocean, sea-level record, tokachi-oki earthquake, western north pacific, Younger Dryas},
	isbn = {1525-2027},
	doi = {10.1029/2004GC000787},
	url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2\&amp;SrcAuth=Alerting\&amp;SrcApp=Alerting\&amp;DestApp=WOS\&amp;DestLinkType=FullRecord;UT=WOS:000228479400002},
	author = {Ohkushi, K. and Ahagon, N. and Uchida, M. and Shibata, Y.}
}
@article {2015,
	title = {Episodic methane release events from Last Glacial marginal sediments in the western North Pacific},
	journal = {Geochemistry Geophysics Geosystems},
	volume = {5},
	year = {2004},
	note = {849mvTimes Cited:13
Cited References Count:73
},
	month = {Aug 19},
	pages = {1525-2027},
	abstract = {[1] According to recent observations of anomalous bottom-simulating reflections (BSR),the northwest Pacific marginal sediments around Japan main islands bear large abundances of methane hydrate [Satoh, 2002]. During the Last Glacial, direct and indirect evidence accumulated from geochemical data suggests that methane episodically released from hydrate trapped in the seafloor sediments [ Dickens et al., 1995; Hinrichs et al., 2003; Kennett et al., 2000]. Here we show that marginal sediments from the western North Pacific contain a hopanoid 17alpha( H), 21beta(H)-hop-22(29)-ene ( diploptene) derived from the activity of methanotrophic bacteria in water column and/or surface sediment during a warming period (Interstadial 3) in the Last Glacial. The carbon isotopic compositions of diploptene range between - 41.0parts per thousand and - 27.9parts per thousand ( relative to PDB). In the horizon indicative of a contribution of methanotrophic bacteria, foraminiferal isotope signals were also found with highly depleted C-13 compositions of planktonic foraminifera ( similar to - 1.9parts per thousand, PDB) and benthic foraminifera ( similar to - 0.8parts per thousand, PDB), suggesting indirect records of enhanced incorporation of C-13-depleted CO2 formed by methanotrophic process that use C-12-enriched methane as their main source of carbon. From combined isotopic data of molecular ( diploptene) and foraminifera, the most prominent signal of methane release was detected in the sediments deposited around 25.4 cal. kyr BP ( similar to 100 year time span), corresponding to the Interstadial 3. This is the first evidence of methane hydrate instability in the open western North Pacific during the Last Glacial. Considering the glacial-interglacial hydrographic conditions in this region, the instability of methane hydrate may be modulated by intermediate water warming and/or the lowering of sea level. Our results suggest that the western North Pacific marginal regions may be a profound effect on rapid global warming climate changes during the Last Glacial.},
	keywords = {atmospheric composition and structure : geochemical cycles, atmospheric methane, carbon isotopes, carbon isotopic fractionation, climate-change, cold seeps, diploptene, Foraminifera, gas-hydrate, geochemistry : isotopic composition/chemistry, geochemistry : organic geochemistry, hydrocarbons, interglacial, intermediate water, methane hydrate, santa-barbara basin, sea sediments, subduction zone, western north pacific},
	isbn = {1525-2027},
	doi = {10.1029/2004GC000699},
	url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2\&amp;SrcAuth=Alerting\&amp;SrcApp=Alerting\&amp;DestApp=WOS\&amp;DestLinkType=FullRecord;UT=WOS:000223543700001},
	author = {Uchida, M. and Shibata, Y. and Ohkushi, K. and Ahagon, N. and Hoshiba, M.}
}
