Kinetic and equilibrium fractionation of O2 isotopologues during air-water gas transfer and implications for tracing oxygen cycling in the ocean
| Autor: | Huanting Hu, Laurence Y. Yeung, Boda Li, Jeanine L. Ash |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
010504 meteorology & atmospheric sciences Mixed layer 010604 marine biology & hydrobiology chemistry.chemical_element General Chemistry Fractionation Solubility equilibrium Oceanography Atmospheric sciences 01 natural sciences Oxygen Equilibrium fractionation chemistry Kinetic fractionation Environmental Chemistry Environmental science Isotopologue Saturation (chemistry) 0105 earth and related environmental sciences Water Science and Technology |
| Zdroj: | Marine Chemistry. 210:61-71 |
| ISSN: | 0304-4203 |
| Popis: | Oxygen isotopologues are useful tools for understanding biogeochemical processes and chemical budgets in the ocean. For example, the triple‑oxygen isotope composition of dissolved oxygen in the ocean mixed layer (i.e., its δ17O and δ18 O values) is widely used to estimate gross oxygen productivity (GOP), a quantity closely related to gross primary productivity. While recent work has demonstrated the importance of upwelling and horizontal transport to these estimates, the isotopic effects of gas exchange when the mixed layer is out of solubility equilibrium have only been measured for 18O/16 O. Oxygen is rarely at 100% saturation in the surface ocean, so most regions experience net ingassing or outgassing ; kinetic fractionation across the air-water boundary is therefore expected to be important. Here, we present the results of air-water gas transfer experiments designed to obtain the kinetic and equilibrium fractionation factors for the four rare O 2 isotopologues 16O17O, 16O18O, 17O18O, and 18O18O relative to 16O16 O. Furthermore, we examine their potential effects on isotopologue-based GOP estimates and connect the observed air-water kinetic fractionation factors to dissolved-phase diffusive isotopic fractionation . These kinetic fractionation effects may provide additional constraints on O 2 cycling at the surface and in the deep ocean. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect