IAEA launches network to monitor isotopes in lakes

The International Atomic Energy Agency has launched the Global Network of Isotopes in Lakes (GNIL), which aims to help countries monitor changes in their lakes and share the data to protect freshwater resources.

The GNIL aims to establish an international database of stable isotopes, water chemistry measurements, and environmental observations to help countries decide where conservation and restoration will have the greatest effect.

"Lakes supply drinking water, food, and jobs for millions of people, yet freshwater ecosystems are among the most threatened on Earth, under pressure from ecosystem degradation, unsustainable water use, and changing environmental conditions," said Najat Mokhtar, IAEA deputy director general and head of the Department of Nuclear Sciences and Applications.

Tracing the signature: Stable hydrogen and oxygen isotopes act as natural fingerprints in water, revealing its origins, age, and movement.

A standard water molecule weighs 18 atomic mass units, but a molecule containing a heavier hydrogen isotope (deuterium) or a heavier oxygen isotope (oxygen-18 rather than oxygen-16) weighs 19 or 20 atomic mass units, respectively.

According to the U.S. National Park Service, when rain forms, heavier water molecules fall first while the lighter molecules travel farther inland and higher up mountains. By measuring the balance between heavy and light isotopes, known as an isotopic signature, scientists can determine where and when precipitation fell and whether it originated from a small or large storm.

For lakes and rivers, more heavy molecules indicate water that entered the system slowly through surface water while more light molecules indicate precipitation as the origin.

Data to enact change: According to the IAEA, the data will provide scientific evidence to guide actions aimed at protecting freshwater resources, fisheries, biodiversity, and lake ecosystems.

"GNIL will help countries collect isotope data from their lakes using a common sampling method and share it, so results can be compared across regions and over time," said Mokhtar.

In its initial phase, the GNIL will focus on establishing common protocols, governance arrangements, and coordinated sampling campaigns to create the foundation for a long-term global lake monitoring system.

Participants will include national agencies, research institutions, laboratories, and partner organizations responsible for collecting and sharing data. The resulting data set will show how lakes respond to changes in rainfall, evaporation, and other environmental pressures.

According to the IAEA, 22 countries have expressed interest in joining the GNIL. The new network builds on the IAEA's longstanding experience in isotope monitoring and complements its existing networks, including the Global Network of Isotopes in Precipitation and the Global Network of Isotopes in Rivers.