@article {jiang_comparing_2023,
	title = {Comparing the isotopic and molecular composition of dissolved organic carbon between the oligotrophic South China Sea and the adjacent North Pacific Ocean: Signals of biodegradation, conservative mixing, and terrestrial input},
	journal = {Marine Chemistry},
	volume = {257},
	year = {2023},
	month = {11/2023},
	pages = {104331},
	abstract = {The cycling of oceanic dissolved organic carbon (DOC) is a crucial component of the global carbon cycle, yet the identification of sources and the mechanisms of its molecular transformation remain poorly understood. This study compared the isotopic and molecular composition of DOC between the oligotrophic South China Sea (SCS) and the adjacent North Pacific Ocean (NPO), and traced both its allochthonous and autochthonous sources as well as its dynamic cycling processes. DOC was collected through solid-phase extraction (SPE) from water samples of both the SCS and NPO. Carbon content, isotopic ratios, and high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) measurements revealed that SPE-DOC contained both labile and refractory fractions. According to our mass balance model, the labile fraction of SPE-DOC exhibited a decline from 11.5 to 12.6~μM in surface waters to a negligible concentration below 1000~m. Conversely, the refractory fraction of SPE-RDOC maintained a relatively consistent value, ranging from 12.7 to 19.0~μM across the entire water column. The vertical distribution patterns of the molecular composition and carbon isotopic ratios jointly indicated that the DOC distributions are shaped by distinct biological and physical processes within different biogeochemical realms of the water column. The production and transformation of the relatively labile DOC fractions were the dominant processes in the epipelagic and mesopelagic zones (upper 1000~m). The extent of diapycnal mixing between the SCS and NPO explained the different vertical distributions of refractory DOC molecules in the bathypelagic oceans. The molecular indices of polyphenol compounds, aromaticity, double bond saturation state, terrestrial mass peaks, and δ13C ratios of SPE-DOC indicated contributions from terrestrial sources, likely riverine input, in the SCS. This study sheds light on the molecular evidence of DOC sources, as well as their transformation and conservative mixing processes along the overturning circulation in marginal seas.},
	keywords = {carbon isotopes, dissolved organic carbon, FT-ICR-MS, North pacific ocean, radiocarbon, south china sea},
	issn = {0304-4203},
	doi = {10.1016/j.marchem.2023.104331},
	url = {https://www.sciencedirect.com/science/article/pii/S0304420323001275},
	author = {Jiang, Peng and Chen, Hongmei and Liu, Zhanfei and Li, Xiaolin}
}
@article {kruger_sediment_2022,
	title = {Sediment organic matter compositional changes in a tropical rift lake as a function of water depth and distance from shore},
	journal = {Organic Geochemistry},
	year = {2022},
	month = {11/2022},
	pages = {104527},
	abstract = {Little is known of modern carbon cycling in East African rift lakes. These large tropical systems with anoxic bottom waters can act as test cases for carbon cycling under future climate change scenarios as well as key sediment repositories for paleolimnology studies and fossil fuel generation. This study is the first to combine stable and radiocarbon isotopic information on bulk sediment and biomarkers (n-alcohols) in an African rift lake by investigating surface sediments collected on a nearshore to offshore transect in northern Lake Malawi. This study is also the first to report radiocarbon content in water column particulate organic, dissolved organic and inorganic carbon from an African rift lake. General surface-sediment trends with increasing water depth were an increase in \%TOC, and decreases in grain size, δ13C and C/N. Carbon radioisotope analyses showed that bulk sedimentary organic matter was modern across the transect. Biomarker data indicated a primarily aquatic origin for sedimentary organic matter at offshore sites; terrestrial material dominated the n-alcohol signature closest to the shore. Protokerogen stable isotope signatures were similar, and radiocarbon was somewhat depleted relative to bulk sediment organic matter. As compared to bulk organic matter, lipids were 13C-depleted throughout the sampling transect and 14C-depleted at the most nearshore location. This indicates an aged lipid carbon source and likely significant diagenetic alteration of modern sources prior to deposition in nearshore sediments, perhaps a combination of soil erosion, in-river processing, sediment resuspension and mobilization, and preferential degradation of younger organic matter in the oxic nearshore region.},
	keywords = {-Alcohols, C/N ratio, carbon isotopes, Lake Malawi, Protokerogen, radiocarbon, Sedimentary organic carbon},
	issn = {0146-6380},
	doi = {10.1016/j.orggeochem.2022.104527},
	url = {https://www.sciencedirect.com/science/article/pii/S0146638022001619},
	author = {Kruger, Brittany R. and Werne, Josef P. and Minor, Elizabeth C.}
}
@article {2925,
	title = {Event-dominated transport, provenance, and burial of organic carbon in the Japan Trench},
	journal = {Earth and Planetary Science Letters},
	volume = {563},
	year = {2021},
	month = {Jan-06-2021},
	pages = {116870},
	abstract = {The delivery of organic carbon (OC) to the ocean{\textquoteright}s deepest trenches in the hadal zone is poorly understood, but may be important for the carbon cycle, contain crucial information on sediment provenance and event-related transport processes, and provide age constraints on stratigraphic sequences in this terminal sink. In this study, we systematically characterize bulk organic matter (OM) and OC signatures (TOC/TN, delta C-13, C-14), as well as those from application of serial thermal oxidation (ramped pyrolysis/oxidation) of sediment cores recovered along an entire hadal trench encompassing high stratigraphic resolution records spanning nearly 2000 years of deposition. We analyze two cores from the southern and northern Japan Trench, where submarine canyon systems link shelf with trench. We compare results with previously published data from the central Japan Trench, where canyon systems are absent. Our analyses enable refined dating of the stratigraphic record and indicate that event deposits arise from remobilization of relatively surficial sediment coupled with deeper erosion along turbidity current pathways in the southern and central study site and from canyon flushing events in the northern study site. Furthermore, our findings indicate deposition of predominantly marine OC within hemipelagic background sediment as well as associated with event deposits along the entire trench axis. This implies that canyon systems flanking the Japan Trench do not serve as a short-circuit for injection of terrestrial OC to the hadal zone, and that tropical cyclones are not major agents for sediment and carbon transfer into this trench system. These findings further support previous Japan Trench studies interpreting that event deposits originate from the landward trench slope and are earthquake-triggered. The very low terrestrial OC input into the Japan Trench can be explained by the significant distance between trench and hinterland (>180 km), and the physiography of the canyons that do not connect to coast and river systems. We suggest that detailed analyzes of long sedimentary records are essential to understand OC transfer, deposition and burial in hadal trenches. (C) 2021 The Author(s). Published by Elsevier B.V.},
	keywords = {carbon isotopes, carbon provenance, carbon transfer, hadal zone event-stratigraphy, Japan Trench, ramped Pyr/Ox},
	issn = {0012821X},
	doi = {10.1016/j.epsl.2021.116870},
	url = {https://apps.webofknowledge.com/InboundService.do?product=WOS\&Func=Frame\&DestFail=https\%3A\%2F\%2Fwww.webofknowledge.com\&SrcApp=search\&SrcAuth=Alerting\&SID=8DxHHPXeqJFVJQqBfHD\&customersID=Alerting\&mode=FullRecord\&IsProductCode=Yes\&AlertId=4d48b20a-7d27-4fa2},
	author = {Schwestermann, T. and Eglinton, T.I. and Haghipour, N. and McNichol, A.P. and Ikehara, K. and Strasser, M.}
}
@article {2823,
	title = {Dual carbon isotope (δ13C and Δ14C) characterization of particulate organic carbon in the Geum and Seomjin estuaries, South Korea},
	journal = {Marine Pollution Bulletin},
	volume = {150},
	year = {2020},
	month = {Jan-01-2020},
	pages = {110719},
	abstract = {We investigated the source, composition, and reactivity of particulate organic carbon (POC) in two contrasting Korean estuary systems, a closed estuary (Geum) (i.e., with an estuary dam at the river mouth) and an open (Seomjin) estuary. A dual isotope (δ13CPOC and Δ14CPOC) approach was applied to surface water samples collected along a salinity gradient in August 2016. Our results indicate that phytoplankton-derived POC was the main contributor to the total POC pool in the reservoir of the Geum estuary, while terrestrial-derived POC predominated the upper Seomjin estuary. A simple binary mixing model using Δ14CPOC revealed a higher modern POC contribution (87{\textendash}90\%) in the Geum estuary reservoir than that (77\%) of the upper Seomjin estuary. Accordingly, it appears that an estuary dam can alter the source and reactivity of POC in a reservoir, which can be transferred to the adjacent coastal ecosystem.},
	keywords = {carbon isotopes, dam, Estuary, Geum estuary, organic carbon, particulate, Seomjin estuary},
	issn = {0025326X},
	doi = {10.1016/j.marpolbul.2019.110719},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0025326X19308756},
	author = {Kang, Sujin and Kim, Jung-Hyun and Ryu, Jong-Sik and Shin, Kyung-Hoon}
}
@article {2871,
	title = {Dissolved organic carbon in basalt-hosted deep subseafloor fluids of the Juan de Fuca Ridge flank},
	journal = {Earth and Planetary Science Letters},
	volume = {513},
	year = {2019},
	month = {Jan-05-2019},
	pages = {156 - 165},
	abstract = {Marine dissolved organic carbon (DOC) is highly depleted in radiocarbon and thus inferred to be largely refractory to removal processes that operate on less than millennial timescales. However, a growing number of reports have shown that a large fraction of marine DOC can be effectively removed during circulation through submarine hydrothermal systems. What is not clear, however, is whether the DOC that remains in hydrothermal fluids is remnant non-reactive DOC from recharged seawater, or DOC that has been largely produced in the subsurface. We collected and characterized warm (\~{}65 {\textdegree}C) hydrothermal fluids from deep (18, 40, 73, 200 m) within the basalt-hosted basement of the Juan de Fuca Ridge flank in the Northeast Pacific Ocean. DOC concentrations in hydrothermal fluids were 9 to 18 μM, much lower than measured in local deep seawater (37.5 μM). DOC C values of -683{\textperthousand} to -856{\textperthousand} were much lower than the C-dissolved inorganic carbon (DIC) values of -880{\textperthousand} to -918{\textperthousand}, while DOC C values of -23.6{\textperthousand} to -27.0{\textperthousand} were much heavier than that of the particulate organic carbon (POC) pool ({\textperthousand}), suggesting that biological production in the subsurface is not a primary source of DOC. Rather, our data suggest that isotopically enriched DOC are selectively removed from recharged seawater, leaving DOC that is very isotopically depleted in the basaltic basement fluids. Despite the removal of 50{\textendash}75\% of DOC in the subsurface, nuclear magnetic resonance (NMR) functional group analyses indicate that aromatic compounds were added to basaltic basement fluids during passage through the deep subseafloor and may partly contribute to the depleted 14C DOC in the ridge-flank basement fluids.},
	keywords = {aromatic organic compound, basaltic basement fluid, carbon isotopes, dissolved organic carbon, Juan de Fuca, selective removal, subseafloor},
	issn = {0012821X},
	doi = {10.1016/j.epsl.2019.02.008},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0012821X19300998},
	author = {Lin, Huei-Ting and Repeta, Daniel J. and Xu, Li and Rapp{\'e}, Michael S.}
}
@article {2752,
	title = {Mangrove sediment carbon stocks along an elevation gradient: Influence of the late Holocene marine regression (New Caledonia)},
	journal = {Marine Geology},
	volume = {404},
	year = {2018},
	month = {Jan-10-2018},
	pages = {60 - 70},
	abstract = {Among blue carbon ecosystems, mangroves are very efficient in storing carbon in their sediments over decadal to millennial time scales. However, this ability varies with numerous parameters, including climate and sea-level variations. In New Caledonia, mangrove ecosystems develop in semi-arid conditions with a typical zonation: Rhizophora spp. colonize the seaward side of the intertidal area, while Avicennia marina develops at higher elevations, just below the salt-flat. Within this context, we determined both the quantity (organic carbon content and carbon stocks) and the characteristics (carbon over nitrogen ratios (C/N), stable carbon and nitrogen isotopes, radiocarbon age) of the organic matter stored beneath each mangrove stands. Carbon stocks were determined down to different limits with depth: approximate extension of the root systems, one-meter depth, and the hard substrate. Within the extension of the root systems, the sediment carbon stock was lower than 100 MgC ha-1 regardless of the mangrove species. This low value resulted directly from the dry climate that limits mangrove productivity. At depth beneath every zone, a buried layer enriched in mangrove-derived organic matter, with C/N values around 40 and δ13C values around -26{\textperthousand} was observed. This layer likely resulted from a sea-level high stand during the late Holocene that allowed a long period of stability of the mangrove, slowly accumulating organic matter within the sediment. In this buried layer, the carbon stock was higher than in the upper sediment and reached up to 665, 255 and 300 MgC ha-1 in the salt-flat zone, the A. marina stand and the R. spp. stand, respectively. The highest stock, determined beneath the salt-flat, was suggested to be related to a period of sea-level stability that lasted ~3000 years, whereas beneath the other zones, which are at lower elevations, mangrove colonization was more recent and the sea-level was continuously decreasing till recently. Sea-level variations, and, specifically current sea-level rise, may strongly influence mangrove development due to their migration along the tidal elevation gradient to maintain the biotic conditions needed for their development.},
	keywords = {Blue carbon, carbon isotopes, carbon sequestration, Coastal wetlands, Sea-level change, Semi-arid mangrove forest},
	issn = {00253227},
	doi = {10.1016/j.margeo.2018.07.005},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0025322717306072},
	author = {Jacotot, Adrien and Marchand, Cyril and Rosenheim, Brad E. and Domack, Eugene W. and Allenbach, Michel}
}
@article {2486,
	title = {Carbon isotope evidence for a northern source of deep water in the glacial western North Atlantic},
	journal = {Proceedings of the National Academy of Sciences},
	volume = {114},
	year = {2017},
	month = {Feb-03-2018},
	pages = {2831 - 2835},
	abstract = {The prevailing view of western Atlantic hydrography during the Last Glacial Maximum (LGM) calls for transport and intermixing of deep southern and intermediate northern end members. However, δ13C and Δ14C results on foraminifera from a sediment core at 5.0 km in the northern subtropics show that there may have also been a northern source of relatively young, very dense, nutrient-depleted water during the LGM (18 ky to 21 ky ago). These results, when integrated with data from other western North Atlantic locations, indicate that the ocean was poorly ventilated at 4.2 km, with better ventilation above and below that depth. If this is a signal of water mass source and not nutrient storage, it would indicate that a previously unrecognized deep water end member originated along the western margin of the Labrador Sea, analogous to dense water formation today around Antarctica and in the Okhotsk Sea.},
	keywords = {carbon isotopes, Last glacial maximum, ocean ventilation, oxygen isotopes, western north atlantic},
	issn = {0027-8424},
	doi = {10.1073/pnas.1614693114},
	url = {http://www.pnas.org/lookup/doi/10.1073/pnas.1614693114https://syndication.highwire.org/content/doi/10.1073/pnas.1614693114http://www.pnas.org/syndication/doi/10.1073/pnas.1614693114},
	author = {Keigwin, Lloyd D. and Swift, Stephen A.}
}
@article {2467,
	title = {Siberian Arctic black carbon sources constrained by model and observation},
	journal = {Proceedings of the National Academy of Sciences},
	volume = {114},
	year = {2017},
	month = {Feb-02-2018},
	pages = {E1054 - E1061},
	abstract = {Black carbon (BC) in haze and deposited on snow and ice can have strong effects on the radiative balance of the Arctic. There is a geographic bias in Arctic BC studies toward the Atlantic sector, with lack of observational constraints for the extensive Russian Siberian Arctic, spanning nearly half of the circum-Arctic. Here, 2 y of observations at Tiksi (East Siberian Arctic) establish a strong seasonality in both BC concentrations (8 ng.m-3 to 302 ng.m-3) and dual-isotope{\textendash}constrained sources (19 to 73\% contribution from biomass burning). Comparisons between observations and a dispersion model, coupled to an anthropogenic emissions inventory and a fire emissions inventory, give mixed results. In the European Arctic, this model has proven to simulate BC concentrations and source contributions well. However, the model is less successful in reproducing BC concentrations and sources for the Russian Arctic. Using a Bayesian approach, we show that, in contrast to earlier studies, contributions from gas flaring (6\%), power plants (9\%), and open fires (12\%) are relatively small, with the major sources instead being domestic (35\%) and transport (38\%). The observation-based evaluation of reported emissions identifies errors in spatial allocation of BC sources in the inventory and highlights the importance of improving emission distribution and source attribution, to develop reliable mitigation strategies for efficient reduction of BC impact on the Russian Arctic, one of the fastest-warming regions on Earth.},
	keywords = {Arctic haze, atmospheric transport modeling, carbon isotopes, Climate change, emission inventory},
	issn = {0027-8424},
	doi = {10.1073/pnas.1613401114},
	url = {http://www.pnas.org/lookup/doi/10.1073/pnas.1613401114https://syndication.highwire.org/content/doi/10.1073/pnas.1613401114http://www.pnas.org/syndication/doi/10.1073/pnas.1613401114},
	author = {Winiger, Patrik and Andersson, August and Eckhardt, Sabine and Stohl, Andreas and Semiletov, Igor P. and Dudarev, Oleg V. and Charkin, Alexander and Shakhova, Natalia and Klimont, Zbigniew and Heyes, Chris and Gustafsson, {\"O}rjan}
}
@article {2638,
	title = {Hidden cycle of dissolved organic carbon in the deep ocean},
	journal = {Proceedings of the National Academy of Sciences},
	volume = {111},
	year = {2014},
	month = {Jan-11-2016},
	pages = {16706 - 16711},
	abstract = {Marine dissolved organic carbon (DOC) is a large (660 Pg C) reactive carbon reservoir that mediates the oceanic microbial food web and interacts with climate on both short and long timescales. Carbon isotopic content provides information on the DOC source via [Formula: see text]C and age via [Formula: see text]C. Bulk isotope measurements suggest a microbially sourced DOC reservoir with two distinct components of differing radiocarbon age. However, such measurements cannot determine internal dynamics and fluxes. Here we analyze serial oxidation experiments to quantify the isotopic diversity of DOC at an oligotrophic site in the central Pacific Ocean. Our results show diversity in both stable and radio isotopes at all depths, confirming DOC cycling hidden within bulk analyses. We confirm the presence of isotopically enriched, modern DOC cocycling with an isotopically depleted older fraction in the upper ocean. However, our results show that up to 30\% of the deep DOC reservoir is modern and supported by a 1 Pg/y carbon flux, which is 10 times higher than inferred from bulk isotope measurements. Isotopically depleted material turns over at an apparent time scale of 30,000 y, which is far slower than indicated by bulk isotope measurements. These results are consistent with global DOC measurements and explain both the fluctuations in deep DOC concentration and the anomalous radiocarbon values of DOC in the Southern Ocean. Collectively these results provide an unprecedented view of the ways in which DOC moves through the marine carbon cycle.},
	keywords = {Carbon cycle, carbon isotopes, dissolved organic carbon, Oceanography, radiocarbon},
	issn = {0027-8424},
	doi = {10.1073/pnas.1407445111},
	url = {http://www.pnas.org/lookup/doi/10.1073/pnas.1407445111https://syndication.highwire.org/content/doi/10.1073/pnas.1407445111},
	author = {Follett, Christopher L. and Repeta, Daniel J. and Rothman, Daniel H. and Xu, Li and Santinelli, Chiara}
}
@article {2508,
	title = {Export of submicron particulate organic matter to mesopelagic depth in an oligotrophic gyre},
	journal = {Proceedings of the National Academy of Sciences},
	volume = {110},
	year = {2013},
	month = {Jun-07-2015},
	pages = {12565 - 12570},
	abstract = {Sixty percent of the world ocean by area is contained in oligotrophic gyres [Longhurst A (1995) Prog Oceanog 36:77-16], the biomass of which is dominated by picophytoplankton, including cyanobacteria and picoeukaryotic algae, as well as picoheterotrophs. Despite their recognized importance in carbon cycling in the surface ocean, the role of small cells and their detrital remains in the transfer of particulate organic matter (POM) to the deep ocean remains disputed. Because oligotrophic marine conditions are projected to expand under current climate trends, a better understanding of the role of small particles in the global carbon cycle is a timely goal. Here we use the lipid profiles, radiocarbon, and stable carbon isotopic signatures of lipids from the North Pacific Subtropical Gyre to show that in the surface ocean, lipids from submicron POM (here called extra-small POM) are distinct from larger classes of suspended POM. Remarkably, this distinct extra-small POM signature dominates the total lipids collected at mesopelagic depth, suggesting that the lipid component of mesopelagic POM primarily contains the exported remains of small particles. Transfer of submicron material to mesopelagic depths in this location is consistent with model results that claim the biological origin of exported carbon should be proportional to the distribution of cell types in the surface community, irrespective of cell size [Richardson TL, Jackson GA (2007) Science 315:838-840]. Our data suggest that the submicron component of exported POM is an important contributor to the global biological pump, especially in oligotrophic waters. 
},
	keywords = {Biogeochemistry, biomarkers, carbon isotopes, Oceanography},
	issn = {0027-8424},
	doi = {10.1073/pnas.1217514110},
	url = {http://www.pnas.org/cgi/doi/10.1073/pnas.1217514110https://syndication.highwire.org/content/doi/10.1073/pnas.1217514110},
	author = {Close, H. G. and Shah, S. R. and Ingalls, A. E. and Diefendorf, A. F. and Brodie, E. L. and Hansman, R. L. and Freeman, K. H. and Aluwihare, L. I. and Pearson, A.}
}
@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.}
}
@article {2190,
	title = {Detecting holocene changes in thermohaline circulation},
	journal = {Proc Natl Acad Sci U S A},
	volume = {97},
	year = {2000},
	note = {Keigwin, L DBoyle, E A
eng
Research Support, U.S. Gov{\textquoteright}t, Non-P.H.S.
2000/03/04 09:00
Proc Natl Acad Sci U S A. 2000 Feb 15;97(4):1343-6.
},
	month = {Feb 15},
	pages = {1343-6},
	abstract = {Throughout the last glacial cycle, reorganizations of deep ocean water masses were coincident with rapid millennial-scale changes in climate. Climate changes have been less severe during the present interglacial, but evidence for concurrent deep ocean circulation change is ambiguous.},
	keywords = {*Climate, *Plankton, Animals, Atlantic Ocean, carbon isotopes, ice, oxygen isotopes, time},
	isbn = {0027-8424 (Print)0027-8424 (Linking)},
	doi = {10.1073/pnas.97.4.1343},
	url = {https://www.ncbi.nlm.nih.gov/pubmed/10677463},
	author = {Keigwin, L. D. and Boyle, E. A.}
}
@article {2291,
	title = {Carbon isotopic fractionation associated with lipid biosynthesis by a cyanobacterium: relevance for interpretation of biomarker records},
	journal = {Geochim Cosmochim Acta},
	volume = {61},
	year = {1997},
	note = {Sakata, SHayes, J M
McTaggart, A R
Evans, R A
Leckrone, K J
Togasaki, R K
eng
Research Support, U.S. Gov{\textquoteright}t, Non-P.H.S.
1997/01/01 00:00
Geochim Cosmochim Acta. 1997;61(24):5379-89.
},
	month = {1997},
	pages = {5379-89},
	abstract = {For the cyanobacterium Synechocystis UTEX 2470, grown photoautotrophically to a logarithmic stage of growth, the total lipid extract is depleted in 13C by 4.8\% relative to average biomass. Depletions observed for acetogenic (straight-chain) lipids range from 7.6 (hexadecanoic acid) to 9.9\% (a C16 n-alkyl chain bound in a polar-lipid fraction), with a mass-weighted average of 9.1\%. Polyisoprenoid lipids fall into two isotopic groups, with phytol, diplopterol, and diploptene depleted by 6.4-6.9\% and bishomohopanol (produced from the extracts by the preparative degradation of bacteriohopanepolyol) depleted by 8.4\%. Analysis of the pattern of depletions indicates that two carbon positions in each C5 biomonomer leading to polyisoprenoid products are probably depleted in 13C relative to average biomass. The depletion of bacteriohopanepolyol relative to other polyisoprenoids can be ascribed to changes that occur over the life of each cell: (1) the 13C content of carbon flowing to lipid biosynthesis decreases as the cell size increases and (2) a greater proportion of the bacteriohopanepolyol which, unlike other polyisoprenoids, is present mainly in the cytoplasm rather than in membranes and is synthesized when cells are larger. Chlorophyll a is depleted relative to average biomass by O.7\%. Given the observed depletion of 13C in phytol, the heteroaromatic, chlorophyllide portion of chlorophyll must be enriched in 13C by 2.7\%. This enrichment is large relative to that in chlorophyllides produced by eukaryotes and may be related to a parallel enrichment of 13C in cyanobacterial glutamic acid. As in many previous investigations of cyanobacterial lipids, long-chain n-alkanes (C22-C29) are found in the extracts. They are, however, enriched in 13C relative to biomass and have isotopic compositions suggesting that they are contaminants of petrochemical origin. Available results indicate that cyanobacterial lipids will be depleted relative to dissolved CO2 that has served as a carbon source by 22-30\% and that a wider range of depletions will be characteristic of eukaryotic products. The absence of long-chain n-alkanes in cyanobacteria reduces the possibility that petroleum ever formed from pre-eukaryotic sedimentary debris.},
	keywords = {*Biomass, Acetic Acid/metabolism, Alkanes/*analysis/chemistry, Biomarkers/chemistry, carbon isotopes, Carbon/*chemistry, Chlorophyll/metabolism, Cyanobacteria/chemistry/*metabolism, Geologic Sediments/*chemistry, Lipids/*biosynthesis, NASA Discipline Exobiology, Non-NASA Center, Palmitic Acid/metabolism, Phytol/metabolism, Pigments, Biological/metabolism},
	isbn = {0016-7037 (Print)0016-7037 (Linking)
},
	url = {https://www.ncbi.nlm.nih.gov/pubmed/11540730},
	author = {Sakata, S. and Hayes, J. M. and McTaggart, A. R. and Evans, R. A. and Leckrone, K. J. and Togasaki, R. K.}
}
@article {2299,
	title = {An isotopic biogeochemical study of Neoproterozoic and Early Cambrian sediments from the Centralian Superbasin, Australia},
	journal = {Geochim Cosmochim Acta},
	volume = {61},
	year = {1997},
	note = {Logan, G ASummons, R E
Hayes, J M
eng
Research Support, U.S. Gov{\textquoteright}t, Non-P.H.S.
1997/01/01 00:00
Geochim Cosmochim Acta. 1997;61(24):5391-409.
},
	month = {1997},
	pages = {5391-409},
	abstract = {Organic matter from Neoproterozoic and Early Cambrian sediments of the Amadeus and Officer basins of the Centralian Superbasin, Australia, has been studied for biomarker distributions and the carbon isotopic compositions of kerogen and individual hydrocarbons. These sediments represent both shallow and deep water marine facies in the older sections and marine and saline lacustrine carbonate deposits in the Cambrian. Hydrocarbon biomarker patterns were found to be quite consistent with the known sedimentary environments and provide valuable insights into the biogeochemical changes which accompanied the transition from a microbially-dominated ocean to the early stages of metazoan radiation. In particular, carbon isotopic data for n-alkyl and isoprenoid lipids presented here, and in earlier studies, showed a reversal in carbon isotopic ordering between the Proterozoic and Phanerozoic. By comparison with the delta 13C of kerogen, n-alkyl lipids from deep-water Proterozoic sediments were enriched in 13C and appear to be derived mainly from heterotrophs whilst open marine Phanerozoic counterparts are 13C depleted and evidently derived mainly from autotrophs. Data from the samples studied here are consistent with a model invoking a change in the redox structure of the ocean, possibly aided by the innovation of faecal pellets.},
	keywords = {Alkanes/analysis/chemistry, Animals, australia, biomarkers, carbon isotopes, Carbon/analysis/*chemistry, Cyanobacteria, Eukaryota, Feces, Fossils, Geologic Sediments/*analysis/chemistry, Hydrocarbons/analysis, NASA Discipline Exobiology, Non-NASA Center, Paleontology, phytoplankton, SEAWATER, Terpenes/analysis, Zooplankton},
	isbn = {0016-7037 (Print)0016-7037 (Linking)
},
	url = {https://www.ncbi.nlm.nih.gov/pubmed/11540731},
	author = {Logan, G. A. and Summons, R. E. and Hayes, J. M.}
}
