Zobrazeno 1 - 10
of 221
pro vyhledávání: '"Daniel M Sigman"'
Publikováno v:
Frontiers in Marine Science, Vol 2 (2015)
The stable nitrogen (N) and oxygen (O) isotope ratios (15N/14N and 18O/16O, respectively) of nitrate (NO3-) were measured during incubations of freshly collected seawater to investigate the effect of light intensity on the isotope fractionation assoc
Externí odkaz:
https://doaj.org/article/d7b372904bc4432487f243d3d36244f6
Autor:
Xuyuan E. Ai, Lena M. Thöle, Alexandra Auderset, Mareike Schmitt, Simone Moretti, Anja S. Studer, Elisabeth Michel, Martin Wegmann, Alain Mazaud, Peter K. Bijl, Daniel M. Sigman, Alfredo Martínez-García, Samuel L. Jaccard
Publikováno v:
Communications Earth & Environment, Vol 5, Iss 1, Pp 1-12 (2024)
Abstract Previous studies suggest that meridional migrations of the Antarctic Circumpolar Current may have altered wind-driven upwelling and carbon dioxide degassing in the Southern Ocean during past climate transitions. Here, we report a quantitativ
Externí odkaz:
https://doaj.org/article/49301435a23546558db055422a37108f
Autor:
Marietta Straub, Alexandra Auderset, Laurence de Leval, Nathalie Piazzon, Damien Maison, Marie-Catherine Vozenin, Jonathan Ollivier, Benoît Petit, Daniel M. Sigman, Alfredo Martínez-García
Publikováno v:
Scientific Reports, Vol 13, Iss 1, Pp 1-9 (2023)
Abstract Studies have suggested that cancerous tissue has a lower 15N/14N ratio than benign tissue. However, human data have been inconclusive, possibly due to constraints on experimental design. Here, we used high-sensitivity nitrogen isotope method
Externí odkaz:
https://doaj.org/article/45e0609ba8cd4fee9c37ac26aa0acc34
Autor:
Jennifer N. Leichliter, Tina Lüdecke, Alan D. Foreman, Nicolas Bourgon, Nicolas N. Duprey, Hubert Vonhof, Viengkeo Souksavatdy, Anne-Marie Bacon, Daniel M. Sigman, Thomas Tütken, Alfredo Martínez-García
Publikováno v:
Communications Biology, Vol 6, Iss 1, Pp 1-13 (2023)
Enamel-bound nitrogen isotopes in modern and fossil mammal teeth preserve dietary and trophic level information. This novel geochemical archive can be used to reconstruct trophic niche in ancient ecosystems.
Externí odkaz:
https://doaj.org/article/3af7a39ce4c241ec8cd254add71e60ce
Publikováno v:
AGU Advances, Vol 4, Iss 6, Pp n/a-n/a (2023)
Abstract The Agulhas Current, like other western boundary currents (WBCs), transports nutrients laterally from the tropics to the subtropics in a subsurface “nutrient stream.” These nutrients are predominantly supplied to surface waters by season
Externí odkaz:
https://doaj.org/article/b017e7673c914eed88460cb5e6907b5d
Autor:
Tanya Marshall, Julie Granger, Karen L. Casciotti, Kirstin Dähnke, Kay-Christian Emeis, Dario Marconi, Matthew R. McIlvin, Abigail E. Noble, Mak A. Saito, Daniel M. Sigman, Sarah E. Fawcett
Publikováno v:
Communications Earth & Environment, Vol 3, Iss 1, Pp 1-10 (2022)
Between 28 and 100% of nitrogen fixation in the South Atlantic occurs within the Angola Gyre and is potentially fuelled by supply of bioavailable iron from margin sediments and excess phosphorus, according to an analysis of observational hydrographic
Externí odkaz:
https://doaj.org/article/9c468c29f8b6400bb33f7cd97bccd4d8
Autor:
Tina Lüdecke, Jennifer N. Leichliter, Vera Aldeias, Marion K. Bamford, Dora Biro, David R. Braun, Cristian Capelli, Jonathan D. Cybulski, Nicolas N. Duprey, Maria J. Ferreira da Silva, Alan D. Foreman, Jörg M. Habermann, Gerald H. Haug, Felipe I. Martínez, Jacinto Mathe, Andreas Mulch, Daniel M. Sigman, Hubert Vonhof, René Bobe, Susana Carvalho, Alfredo Martínez-García
Publikováno v:
Frontiers in Ecology and Evolution, Vol 10 (2022)
The analyses of the stable isotope ratios of carbon (δ13C), nitrogen (δ15N), and oxygen (δ18O) in animal tissues are powerful tools for reconstructing the feeding behavior of individual animals and characterizing trophic interactions in food webs.
Externí odkaz:
https://doaj.org/article/a4fc16af692d4f0bbf56896caa8f409f
Autor:
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
Publikováno v:
Geochemistry, Geophysics, Geosystems, Vol 23, Iss 8, Pp n/a-n/a (2022)
Abstract 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,
Externí odkaz:
https://doaj.org/article/6263d79b02e1498a81c813ab8e8acead
Autor:
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
Publikováno v:
Geochemistry, Geophysics, Geosystems, Vol 21, Iss 2, Pp n/a-n/a (2020)
Abstract 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
Externí odkaz:
https://doaj.org/article/50a2c5dc35c04ee89c42ca163c88d5e4
Autor:
Tanya A. Marshall, Daniel M. Sigman, Lisa M. Beal, Alan Foreman, Alfredo Martínez‐García, Stéphane Blain, Ethan Campbell, François Fripiat, Robyn Granger, Eesaa Harris, Gerald H. Haug, Dario Marconi, Sergey Oleynik, Patrick A. Rafter, Raymond Roman, Kolisa Sinyanya, Sandi M. Smart, Sarah E. Fawcett
Publikováno v:
Journal of Geophysical Research: Oceans
The greater Agulhas Current region is an important component of the climate system, yet its influence on carbon and nutrient cycling is poorly understood. Here, we use nitrate isotopes (δ15N, δ18O, Δ(15–18) = δ15N–δ18O) to trace regional wat
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ff5c5db3fdfb0ac42f0f6374470a3a53
https://hdl.handle.net/21.11116/0000-000D-3CBB-E
https://hdl.handle.net/21.11116/0000-000D-3CBB-E