That should be usefull to add these new variables :
Oxygen-18 and oxygen-17 isotope ratio in precipitation water
Oxygen-18 and oxygen-17 isotope ratio of groundwater
Oxygen-18 and oxygen-17 isotope ratio of karst water
Please find the new variables you suggested at the following uri:
Oxygen-18 and oxygen-17 isotope ratio of groundwater : https://w3id.org/ozcar-theia/c_8e842580
Oxygen-18 and oxygen-17 isotope ratio of karst water : https://w3id.org/ozcar-theia/c_ba869919
Oxygen-18 and oxygen-17 isotope ratio of precipitation water : https://w3id.org/ozcar-theia/c_584dca72
Oxygen-18 and oxygen-17 isotope ratio of surface water : https://w3id.org/ozcar-theia/c_85894a22