In depth freshened water beneath the ocean ground confirmed for the primary time | Colorado School of Mines

For the primary time, scientists have immediately documented and extensively sampled a freshened water system beneath the ocean ground. 

This main discovery comes from the preliminary analyses of sediment cores recovered throughout a world scientific expedition led by Co-Chief Scientists Brandon Dugan, professor and affiliate division head of geophysics at Colorado School of Mines, and Rebecca Robinson, professor of oceanography on the University of Rhode Island.

The cores, retrieved from deep under the ocean ground, are actually being opened, analyzed and sampled by the science group, throughout virtually a month of intensive collaborative work on the University of Bremen. 

During January and February, the expedition’s scientists are working facet by facet to uncover new insights into the formation, evolution and significance of this newly documented subseafloor freshwater system.

“We were excited to see that freshened water exists in multiple kinds of sediments – both marine and terrestrial,” Dugan mentioned. “Freshened water in such different materials will help us understand the conditions that emplaced the water. Further analyses that are conducted by the science team will help to find out where and especially when the water was placed here.”

The aim of the expedition went far past gathering sediment cores. Scientists additionally got down to pattern the water saved inside the sediments, together with from sandy layers that act as aquifers and from clay layers that often maintain the water in place beneath the seafloor, often called aquitards. 

Although roughly 70 p.c of Earth’s floor is roofed by water, vital volumes of water additionally transfer and are saved under floor. Many coastal communities rely upon land-based aquifers for his or her freshwater provide. What fewer individuals notice is that, in lots of components of the world these aquifers proceed offshore, containing zones of freshened, barely briny water beneath the ocean ground. Scientists have recognized these offshore programs existed since 1976, however they’ve remained just about unexplored till now. 

During this expedition, the science group has efficiently documented and sampled freshened water inside a zone almost 200 metres thick under the seafloor.

Shedding mild on related water aquifers world wide

The method used throughout IODP³-NSF Expedition 501 is not going to solely deepen understanding of offshore freshened groundwater programs off the coast of New England, however may also make clear related hidden water aquifers world wide. 

Because many coastal areas depend on groundwater for his or her freshwater provide, the expedition’s preliminary findings are extremely related to society. The analysis may also reveal how vitamins comparable to nitrogen cycle via continental shelf sediments and the way these processes affect the abundance and variety of microbes dwelling in these environments. These targets align carefully with the 2050 Science Framework for Ocean Research Drilling – one of many foundations of the IODP³ scientific programme. Ultimately, the expedition’s analysis will assist to decipher how sediments and fluids cycle via the Earth system and enhance our data about sea stage adjustments and freshwater move beneath the seabed alongside our coastal cabinets. 

“The researchers will continue to work on and with the samples to decipher more – for example, to date the groundwater more accurately which is critical to advancing our knowledge,” Robinson mentioned.

The expedition is a joint collaboration between the International Ocean Drilling Programme (IODP³) and the US National Science Foundation (NSF). The cores had been retrieved throughout offshore operations between May and August 2025. For onshore operations the science group has met on the Bremen Core Repository at MARUM – Center for Marine Environmental Sciences of the University of Bremen (Germany).

 “We greatly appreciate being able to conduct this advanced research at MARUM, supported by its world-class laboratories, exceptional facilities, and dedicated staff,” Dugan mentioned.

The cores might be archived and made accessible for additional scientific analysis for the scientific neighborhood after a one year-moratorium interval. All expedition information might be open entry within the IODP³ Mission Specific Platform (MSP) information portal in PANGAEA, and ensuing outcomes might be printed.

A complete of 40 science group members from 13 nations – Australia, China, France, Germany, India, Italy, Japan, Netherlands, Portugal, Sweden, Switzerland, United Kingdom and U.S. – have taken half within the expedition’s off and on-shore phases.