Isotope Hydrology
Isotope hydrology is concerned with the isotopic signatures of water. Hydrologists who specialize in isotope hydrology are able to determine the origin and age of any given sample of water. Examining the isotopic "fingerprint" of water molecules entails a study of the variable number of neutrons in the nucleus. This up-close look at water is aiding scientists in creating more nuanced maps of water worldwide, and allowing them further insight into the origin of our planet's water resources.