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1. Non‐Equilibrium Fractionation Factors for D/H and 18 O/ 16 O During Oceanic Evaporation in the North‐West Atlantic Region

   https://doi.org/10.1029/2022JD037076  

   Zannoni, D. ; Steen‐Larsen, H. C. ; Peters, A. J. ; Wahl, S. ; Sodemann, H. ; Sveinbjörnsdóttir, A. E. ( November 2022 , Journal of Geophysical Research: Atmospheres)

   Ocean isotopic evaporation models, such as the Craig‐Gordon model, rely on the description of nonequilibrium fractionation factors that are, in general, poorly constrained. To date, only a few gradient‐diffusion type measurements have been performed in ocean settings to test the validity of the commonly used parametrization of nonequilibrium isotopic fractionation during ocean evaporation. In this work, we present 6 months of water vapor isotopic observations collected from a meteorological tower located in the northwest Atlantic Ocean (Bermuda) with the objective of estimating nonequilibrium fractionation factors (k, ‰) for ocean evaporation and their wind speed dependency. The Keeling Plot method and Craig‐Gordon model combination were sensitive enough to resolve nonequilibrium fractionation factors during evaporation resulting into mean values ofk₁₈ = 5.2 ± 0.6‰ andk₂ = 4.3 ± 3.4‰. Furthermore, we evaluate the relationship betweenkand 10‐m wind speed over the ocean. Such a relationship is expected from current evaporation theory and from laboratory experiments made in the 1970s, but observational evidence is lacking. We show that (a) in the observed wind speed range [0–10 m s⁻¹], the sensitivity ofkto wind speed is small, in the order of −0.2‰ m⁻¹ s fork₁₈, and (b) there is no empirical evidence for the presence of a discontinuity between smooth and rough wind speed regime during isotopic fractionation, as proposed in earlier studies. The water vapord‐excess variability predicted under the closure assumption using thekvalues estimated in this study is in agreement with observations over the Atlantic Ocean.

    

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2. Measurements of 18 O 18 O and 17 O 18 O in the atmosphere and the role of isotope-exchange reactions: 18 O 18 O AND 17 O 18 O IN THE ATMOSPHERE

   https://doi.org/10.1029/2012JD017992  

   Yeung, Laurence Y. ; Young, Edward D. ; Schauble, Edwin A. ( September 2012 , Journal of Geophysical Research: Atmospheres)
3. Iron Vanadates Synthesized from Hydrothermal Brines: Rb 2 FeV 6 O 16 , Cs 2 FeV 6 O 16 , and SrFe 3 V 18 O 38

   https://doi.org/10.1002/ejic.201900799  

   Smith Pellizzeri, Tiffany M. ; McMillen, Colin D. ; Wen, Yimei ; Chumanov, George ; Kolis, Joseph W. ( November 2019 , European Journal of Inorganic Chemistry)

   null (Ed.)
4. Growth rates, stable oxygen isotopes ( δ 18 O), and strontium (Sr/Ca) composition in two species of Pacific sclerosponges ( Acanthocheatetes wellsi and Astrosclera willeyana ) with δ 18 O calibration and application to paleoceanography

   https://doi.org/10.1029/2009JC005586  

   Grottoli, Andréa G. ; Adkins, Jess F. ; Panero, Wendy R. ; Reaman, Daniel M. ; Moots, Kate ( January 2010 , Journal of Geophysical Research)
5. A 600 kyr reconstruction of deep Arctic seawater δ 18 O from benthic foraminiferal δ 18 O and ostracode Mg ∕ Ca paleothermometry

   https://doi.org/10.5194/cp-19-555-2023  

   Farmer, Jesse R. ; Keller, Katherine J. ; Poirier, Robert K. ; Dwyer, Gary S. ; Schaller, Morgan F. ; Coxall, Helen K. ; O'Regan, Matt ; Cronin, Thomas M. ( January 2023 , Climate of the Past)

   Abstract. The oxygen isotopic composition of benthic foraminiferal tests (δ18Ob) is one of the pre-eminent tools for correlating marine sediments and interpreting past terrestrial ice volume and deep-ocean temperatures. Despite the prevalence of δ18Ob applications to marine sediment cores over the Quaternary, its use is limited in the Arctic Ocean because of low benthic foraminiferal abundances, challenges with constructing independent sediment core age models, and an apparent muted amplitude of Arctic δ18Ob variability compared to open-ocean records. Here we evaluate the controls on Arctic δ18Ob by using ostracode Mg/Ca paleothermometry to generate a composite record of the δ18O of seawater (δ18Osw) from 12 sediment cores in the intermediate to deep Arctic Ocean (700–2700 m) that covers the last 600 kyr based on biostratigraphy and orbitally tuned age models. Results show that Arctic δ18Ob was generally higher than open-ocean δ18Ob during interglacials but was generally equivalent to global reference records during glacial periods. The reduced glacial–interglacial Arctic δ18Ob range resulted in part from the opposing effect of temperature, with intermediate to deep Arctic warming during glacials counteracting the whole-ocean δ18Osw increase from expanded terrestrial ice sheets. After removing the temperature effect from δ18Ob, we find that the intermediate to deep Arctic experienced large (≥1 ‰) variations in local δ18Osw, with generally higher local δ18Osw during interglacials and lower δ18Osw during glacials. Both the magnitude and timing of low local δ18Osw intervals are inconsistent with the recent proposal of freshwater intervals in the Arctic Ocean during past glaciations. Instead, we suggest that lower local δ18Osw in the intermediate to deep Arctic Ocean during glaciations reflected weaker upper-ocean stratification and more efficient transport of low-δ18Osw Arctic surface waters to depth by mixing and/or brine rejection. 

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