Contents -- 1. The Hydrosphere - An Overview -- 2. The Isotopes of Hydrogen and Oxygen -- 2.1. Measurement techniques -- 2.2. The natural abundance of isotopes of oxygen and hydrogen -- 3. Isotope Fractionation -- Introduction -- 3.1. Isotope fractionation under equilibrium conditions (Thermodynamic fractionation processes) -- 3.2. Isotope fractionation accompanying transport processes -- 4. Models of Isotopic Change in the Water Cycle -- 4.1. Closed equilibrium system -- 4.2. Open equilibrium systems - the Rayleigh Equation -- 4.2.1. Systems without inflow -- 4.2.2. Systems with both in- and outflow -- 4.3. Evaporation under natural conditions -- 4.3.1. Isotope composition of the evaporation flux - dE -- 4.3.2. Postscript -- 4.4. The "Isotope Transfer Function" (ITF) -- 5. The Ocean System and the Marine Atmosphere -- 5.1. Isotope composition of the ocean waters -- 5.2. Water in themarine atmosphere -- 5.2.1. Isotopic composition ofmarine vapour -- 5.2.2. Precipitation over the oceans -- 6. Clouds and Precipitation -- 6.1. The isotopic composition of the precipitation -- 6.1.1. Snow, hail and other solid phase precipitation -- 6.1.2. Precipitation over the continents -- 6.1.3. The Local Meteoric Water Lines (LMWL) -- 6.2. The isotope composition of the atmospheric moisture -- 7. Snow and Snowmelt Processes -- 7.1. Solid precipitation elements -- 7.2. Snow accumulation and changes in the snowpack -- 7.3. The snowmelt process -- 8. The Land-Biosphere-Atmosphere Interface -- 8.1. Isotope change in the land-biosphere-atmosphere interface -- 8.1.1. Above-surface processes -- 8.1.2. Local surface runoff -- 8.1.3. The local percolation flux -- 9. Surface Waters -- 9.1. The surface runoff -- 9.2. Isotopic hydrograph separation -- 9.3. River systems and the "Isotopic River Continuum Model" -- 9.4. Open waters (ponds to lakes).

9.4.1. The Index-Lake concept -- 9.4.2. Verticalmixing in lakes -- 9.4.3. Ice covered lakes -- 9.4.4. Lakeswithout surface outflow -- 9.5. Coupled and complex evaporative systems -- 10. Water in Soils and Plants -- 10.1. Infiltration, percolation and inter.flow(*) -- 10.2. Evaporation fromwithin the soil -- 10.2.1. The soil-mediated recharge flux -- 10.3. Water uptake by plants -- 10.4. Water in the plant tissues -- 11. Saline Waters -- 11.1. Sources of salinity in the hydrologic cycle -- 11.2. Salinisation mechanisms and their isotopic signature -- 11.2.1. Evaporation of saline waters -- 11.2.2. Freezing of saline solutions -- 11.2.3. Ultra.ltration -- 12. Sub-Surface Waters -- 12.1. Circulating (meteoric) groundwater -- 12.2. Paleowaters -- 12.3. Geothermal systems -- 12.4. Formation water -- 13. The Continental Scale Water Balance and Its Isotopic Signature -- 13.1. Water isotopes on the continental lee-side -- 13.2. Isotope aided GCMs -- 14. Isotopes and Climate Change -- 14.1. Oxygen and Hydrogen isotope composition of proxy materials as tools in paleo-climate research -- 14.1.1. Glaciers -- 14.1.2. Ocean and lake sediments -- 14.2. Effect of climate change on the isotope signature in the hydrologic cycle -- References -- Appendix: Tritium in the Water Cycle -- Index.