Ancient Groundwater Contributes Carbon to Surface Water

July 10, 2019

New Australian Nuclear Science & Technology Organization study examines groundwater

Groundwater in Australia has been contributing carbon to food webs—an interconnection of food chains in an ecological community—through surface water, according to a study conducted by the Australian Nuclear Science and Technology Organization (ANSTO).

The study also helped identify groundwater-dependent ecosystems and the length of the ecosystems' dependency on water as energy. According to, the research also showed radiocarbon can be used to trace groundwater influences in surface water ecosystems—such as water produced from groundwater extraction and mining.

According to, the study examined the link between groundwater and surface food webs in the Great Artesian Basin. This basin is the largest and deepest artesian basin in the world and contains water that is one million years old. The study, originally published in the “Journal of Geophysical Research: Biogeosciences,” examines ancient carbon in aquatic animals in the arid and semi-arid regions of Australia. 

"We suspected that aquatic ecosystems in areas subject to groundwater flows from the Great Artesian Basin might be using carbon from subterranean groundwater as source energy," said Dr. Debashish Mazumder, lead author of the study, to

Mazumder used data from other ANSTO studies by groundwater experts Dr. Suzanne Hollins and Dr. Karina Meredith. Researchers in the ANSTO study used carbon and nitrogen with radiocarbon to determine the most dominant of the carbon sources. According to, they found older carbon is the most dominant carbon source of the whole food chain. This includes fish as old as 11,000 years old.

"Our analysis using stable and radiocarbon values of dissolved inorganic carbon, organic carbon, algae and fish confirmed that carbon from very old groundwater entered the food chain and reached the highest tropic level in fish," said Professor Neil Saintilan of Macquarie University, who also contributed to the study, to