# 4.1b Environmental O & H

Mechanisms of O and H fractionation

The water cycle

* Pools: groundwater, soil, ocean, biomass, atmosphere/air, clouds
* Fluxes: evaporation/condensation, transpiration, root uptake, precipitation, advection, sublimation, percolation, infiltration

**Temperature Effect:** Precipitation isotope delta values decrease as temperature increases <img src="https://789240665-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FShvdx4K6BBMxfuVPr2NP%2Fuploads%2Fa6m8C65KgWM9zalfC7S2%2FScreen%20Shot%202023-05-12%20at%208.34.52%20AM.png?alt=media&#x26;token=127673b1-472f-4ad5-948b-2410d8b9c349" alt="" data-size="line">

* Salinity is a good predictor of O values in the ocean because evaporation and circulation drive both&#x20;

**Continental effect / distance from source:** precipitation isotope delta values decrease with distance from source (the ocean)&#x20;

**Latitudinal / Altitude effect:** precipitation isotope delta values decrease with increasing latitude or altitude <img src="https://789240665-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FShvdx4K6BBMxfuVPr2NP%2Fuploads%2Fhf43Dvan9672BIfw3EVQ%2FScreen%20Shot%202023-05-12%20at%208.40.49%20AM.png?alt=media&#x26;token=70dd7109-8af3-4ccd-bd94-f70c4629af24" alt="" data-size="line">

**Amount Effect:** Precipitation isotope delta values decrease with increasing raingall because they rain out. Generally follos Rayleigh model&#x20;

Isoscape Uses:&#x20;

* Tracing movement (sea or land)&#x20;
* Archives of past climate / paleo-climate
* Tracing origins of water&#x20;
* Trace water-rock reactions (like hydrothermal vents)&#x20;

## References

#### <mark style="color:purple;">Gat 1996</mark>

Summary of environmental fractionation, mostly of soil and atmosphere&#x20;
