Results 151 to 160 of about 6,443 (255)

Surface geoenvironments shape organic matter inputs in iron-ore caves of Carajás, southeastern Amazonia. [PDF]

PLoS One
Reis LS, Felix Guimarães JT, de Sá CYG, Bernard E, Ruiz Pessenda LC, Gastauer M, de Oliveira PE.   +6 more
europepmc   +1 more source

Mixotrophy emerges as an optimal strategy in mature waters of the Amazon River plume. [PDF]

Commun Biol
Fernández-Carrera A, Choisnard N, Wodarg D, Liskow I, Subramaniam A, Montoya JP, Voss M, Loick-Wilde N.   +7 more
europepmc   +1 more source

Reaffirming the Consistency of the Original Stock of NBS 19 Limestone and Its Byproduct With Finer Grain Size for δ13C and δ18O Calibrations—Both Distributed Internationally

Rapid Communications in Mass Spectrometry, Volume 40, Issue 18, 30 September 2026.
ABSTRACT Rationale Approximately 3–4 kg of NBS 19 limestone, prepared in 1982 by the U.S. Geological Survey (USGS), serves as a primary reference for the carbon isotope scales VPDB and VPDB‐LSVEC and the oxygen isotope scale VPDB. Its consensus values are +1.95‰ for δ13C and −2.2‰ for δ18O measurements.
Haiping Qi, Tyler B. Coplen, Lauren T. Reid, Stanley J. Mroczkowski   +3 more
wiley   +1 more source

Altitude-adaptive water use strategies of grassland are constrained by air dryness and stoichiometry in southwest of China. [PDF]

Front Plant Sci
Bai J, Zhai D, Xu Y, Chen D, Wang W, Xu Z, Si Y, Yang F, Sun M, Zhang Y, Chen Z, Yang J, Cui W, Yu J, Cheng X.   +14 more
europepmc   +1 more source

Three New Calcium Formate Reference Materials for δ13C Measurements and a Redetermination of the R(13C/12C) Ratio for VPDB Based on Proton Nuclear Magnetic Resonance Measurements

Rapid Communications in Mass Spectrometry, Volume 40, Issue 18, 30 September 2026.
ABSTRACT Rationale Isotope ratio mass spectrometry (IRMS) and proton nuclear magnetic resonance (1H NMR) spectroscopy are independent techniques for determining the isotope ratio R(13C/12C) in organic compounds. However, the lack of suitable reference materials has limited intercalibration of results from these methods.
David W. Hoffman, Cornelia Rasmussen, Arndt Schimmelmann, Lauren T. Reid, Haiping Qi, Tyler B. Coplen   +5 more
wiley   +1 more source

Rivers under stress: geochemical changes along a rural-urban gradient during extreme hydrological events (Greve River, Italy). [PDF]

Environ Geochem Health
Ferrari M, Biagi R, Venturi S, Frezzi F, Tassi F.   +4 more
europepmc   +1 more source

Navigating the Flames: Comparative Analysis of Cremation Practices in the Roman and Early Medieval Periods at Gbely‐Kojatín (SK) and Přítluky (CZ)

Archaeometry, Volume 68, Issue 4, Page 818-830, August 2026.
ABSTRACT Cremation became the dominant funerary practice in the Middle Danube Region during the Roman Period (RP) (1st–4th century) and reappeared in the Early Medieval Ages (EMA) (6th/7th–8th century). This study aims to reconstruct differences in cremation conditions from the Gbely‐Kojatín site (Slovakia, RP and EMA) and the Přítluky site (Czech ...
Katarína Hladíková, Anna Pankowská, Marek Hladík, Pavla Kučerová, Rastislav Milovský   +4 more
wiley   +1 more source

Volcanism and basalt weathering drove Ordovician climatic cooling. [PDF]

Nat Commun
Zhao H, Zhang L, Algeo TJ, Lyu Z, Wang X, Hao F.   +5 more
europepmc   +1 more source

Soil phosphorus drives subcontinental patterns of carbon isotope discrimination across Australia

New Phytologist, Volume 251, Issue 3, Page 1038-1053, August 2026.
Summary Several transects have been established to study the sensitivity of carbon isotope discrimination (Δ13C) in woody plants to mean annual precipitation (MAP) across Australia. These have shown a surprising divergence in Δ13C‐MAP sensitivity among subcontinental regions.
Iftakharul Alam, Alexander W. Cheesman, Graham D. Farquhar, Thomas J. Givnish, Martin G. De Kauwe, Ernst‐Detlef Schulze, Andrea C. Westerband, Ian J. Wright, Lucas A. Cernusak   +8 more
wiley   +1 more source

Cooling-induced intensification of ocean anoxia in the mid-Paleozoic. [PDF]

Sci Adv
Wang Y, Wignall PB, Mills BJW, Dickson AJ, Loydell DK, Xiong Y, Xu Z, Peakall J, Poulton SW.   +8 more
europepmc   +1 more source