Results 71 to 80 of about 128,824 (253)

Laboratory Assessment of the Impact of Chemical Oxidation, Mineral Dissolution, and Heating on the Nitrogen Isotopic Composition of Fossil‐Bound Organic Matter

Geochemistry, Geophysics, Geosystems, 2022
Fossil‐bound organic material holds great potential for the reconstruction of past changes in nitrogen (N) cycling. Here, with a series of laboratory experiments, we assess the potential effect of oxidative degradation, fossil dissolution, and thermal ...
Alfredo Martínez‐García, Jonathan Jung, Xuyuan E. Ai, Daniel M. Sigman, Alexandra Auderset, Nicolas N. Duprey, Alan Foreman, François Fripiat, Jennifer Leichliter, Tina Lüdecke, Simone Moretti, Tanja Wald   +11 more
doaj   +1 more source

Nitrogen isotope variations in the Solar System [PDF]

Nature Geoscience, 2015
The solar wind, cometary ices, and inner Solar System bodies exhibit distinct nitrogen isotopic compositions. A synthesis of these analyses suggests that these distinct reservoirs may be the result of early fractionation processes.
Füri, Evelyn, Marty, Bernard
openaire   +2 more sources

The Dual Origin of the Terrestrial Atmosphere

, 2003
The origin of the terrestrial atmosphere is one of the most puzzling enigmas in the planetary sciences. It is suggested here that two sources contributed to its formation, fractionated nebular gases and accreted cometary volatiles.
Abe, Anders, Ballentine, Balsiger, Bar-Nun, Bar-Nun, Benz, Bockelée-Morvan, Burnard, Busemann, Caffee, Chen, Chyba, Chyba, Dauphas, Dauphas, Dauphas, Dauphas, Dauphas, Dauphas, Delsemme, Delsemme, Eberhardt, Holland, Honda, Honda, Hunten, Hunten, Ihaka, Iro, Jagoutz, Kerridge, Kimura, Kleine, Kunz, Laufer, Marty, Marty, Marty, Maréchal, Mathew, Mathew, Matsui, Matsumoto, Mazor, Meier, Meisel, Meisel, Morbidelli, Moreira, Moreira, Nicolas Dauphas, Notesco, Notesco, Owen, Owen, Owen, Owen, Ozima, Ozima, Ozima, Pepin, Pepin, Pepin, Pepin, Pepin, Pepin, Podosek, Porcelli, Porcelli, Press, Sagan, Sarda, Sasaki, Schoenberg, Shoemaker, Swindle, Swindle, Tolstikhin, Trieloff, Walker, Wieler, Wieler, Yamamoto, Yin, Yokochi, Zahnle, Zahnle, Zahnle, Zahnle, Zahnle, Zhang   +91 more
core   +1 more source

Human pressures on two estuaries of the Iberian Peninsula are reflected in food web structure [PDF]

, 2019
As a result of the increased urban and agricultural development in coastal environments, estuaries are among the most modified and threatened aquatic ecosystems.
Donázar Aramendía, Iñigo Javier, García Asencio, Isabel, García Gómez, José Carlos, Megina Martínez, César, Miró Recio-Mensaque, Juan Miguel, Sánchez Moyano, Juan Emilio   +5 more
core   +1 more source

Nitrogen isotope effects induced by anammox bacteria [PDF]

Proceedings of the National Academy of Sciences, 2013
Significance Nitrogen is essential for all organisms and limits primary production in the ocean. It is mainly lost from low-oxygen environments by the activity of microorganisms that convert fixed nitrogen to N 2 gas.
Brunner, Benjamin, Contreras, Sergio, Lehmann, Moritz F., Matantseva, Olga, Rollog, Mark, Kalvelage, Tim, Klockgether, Gabriele, Lavik, Gaute, Jetten, Mike S. M., Kartal, Boran, Kuypers, Marcel M. M.   +10 more
openaire   +5 more sources

Modeling pN2 through Geological Time: Implications for Planetary Climates and Atmospheric Biosignatures [PDF]

, 2016
Nitrogen is a major nutrient for all life on Earth and could plausibly play a similar role in extraterrestrial biospheres. The major reservoir of nitrogen at Earth's surface is atmospheric N2, but recent studies have proposed that the size of this ...
Buick, R., Johnson, B., Kipp, M. A., Koehler, M. C., Schwieterman, E. W., Stüeken, E. E.   +5 more
core   +2 more sources

A basin‐wide carbon‐related proxy dataset in arid China

Geoscience Data Journal
Closed basin accounts for about one‐fifth of the global land area and is an important part of the global terrestrial carbon cycle. Due to its relatively close geographical environment and independent carbon cycling system, it is an ideal place to study ...
Yu Li, Yaxin Xue, Mingjun Gao, Zhansen Zhang, Simin Peng, Junjie Duan   +5 more
doaj   +1 more source

Sulphur-isotope compositions of pig tissues from a controlled feeding study [PDF]

, 2017
Sulphur-isotope determinations are becoming increasingly useful for palaeodietary reconstruction, but knowledge of isotopic discrimination between diet and various tissues remains inadequate. In this study, we explore the sensitivity of δ34Stissue values
Evershed, Richard P., Lewis, Jamie, Miller, Bevis, Newton, Jason, Stewart, Alan, Tarlton, John F., Webb, Emily C.   +6 more
core   +2 more sources

The Nitrogen Isotopic Composition of Tissue and Shell‐Bound Organic Matter of Planktic Foraminifera in Southern Ocean Surface Waters

Geochemistry, Geophysics, Geosystems, 2020
We present the first nitrogen isotope (δ15N) measurements of planktic foraminifera, paleoceanographically important zooplankton, from the nutrient‐rich waters of the modern Southern Ocean. Foraminifera were collected from net tows in the Subantarctic and
Sandi M. Smart, Sarah E. Fawcett, Haojia Ren, Ralf Schiebel, Emily M. Tompkins, Alfredo Martínez‐García, Luca Stirnimann, Alakendra Roychoudhury, Gerald H. Haug, Daniel M. Sigman   +9 more
doaj   +1 more source

Identification of nitrate sources and transformation in karst cave water using hydrochemistry and NO3− isotopes (δ15N/δ18O) combined with a Bayesian mixing model

All Earth
Nitrogen mainly exists as nitrate in aqueous environments. In karst areas, nitrate pollution caused by anthropogenic activities severely endangers aqueous systems.
Dan Su, Zhongfa Zhou, Xiaohuan Gong, Lihui Yan, Shengjun Ding, Hui Dong, Ye Zhang, Xiaoduo Wang   +7 more
doaj   +1 more source