2. Isotopes and the water cycle

2.1 Atmospheric tracing

Aerosols are the main source of chemical elements transported by rainfall. The atmosphere, through dry deposition (aerosols) or wet deposition (rain), is recognized as a major source of dissolved elements in continental hydrosystems (surface water and groundwater). The components dissolved in rainwater can be divided into three groups:

• those derived from marine aerosols ;

• those derived from terrigenous aerosols (soil dust, biological emissions);

• those derived from human activities (industry, agriculture, etc.).

In order to gain a better understanding of rainfall inputs to watersheds on a local scale, isotope ratios...