Â鶹APP

Geoscientists from the University of Leicester will set sail for New England this month to collect samples of water sealed below the sea floor for potentially thousands of years. 

They are joining the science vessel, the Liftboat Robert, to study the properties of freshwater systems with ancient water that are present in sediment up to 100 miles offshore. The team of scientists will core up to 550 metres below the ocean floor to reach the aquifer and collect samples. 

In the 1960's scientists were quite surprised when they looked at their data: it clearly showed that there was fresh or freshened water under the ocean floor. How did it get there? How long has it been there? Scientists have been trying to find answers to these questions since their intriguing discovery. Starting in May, an international team of scientists has embarked on an expedition to take a closer look at, and take samples of, this freshened water stored beneath the ocean floor. Professor Karen Johannesson of University of Massachusetts Boston and Professor Brandon Dugan of Colorado School of Mines are the Co-Chief Scientists of this international expedition. Samples will be collected using the Liftboat Robert, which departed from the port of Bridgeport on 19 May.

Seventy percent of the Earth's surface is covered with water, but water also flows beneath its surface. Most coastal communities rely on traditional onshore aquifers for freshwater, however, in many locations worldwide onshore aquifers may have an offshore component where freshened water exists under the ocean floor. Even though the existence of these waters has been known for decades they remain virtually unexplored. This will change through the ground-breaking research to be completed during this expedition, which is a collaboration between the Â鶹APP Ocean Drilling Programme (IODP³) and the US National Science Foundation (NSF). For the first time scientists on IODP³-NSF Expedition 501 “New England Shelf Hydrogeology” will take water and sediment samples from beneath the ocean floor on the New England Shelf with the intention of understanding this offshore aquifer system. 

Researchers are seeking more knowledge about the origin of freshened groundwater in offshore aquifers so that they can confirm or dismiss the existing hypotheses. For example, current hypotheses are that the water could have charged the aquifers at a time when sea-level was 100 meters lower than it is today, or perhaps it was generated under an ice sheet or pro-glacial lake during a glacial period such as the ice age approximately 20,000 years ago. 

A team of University of Leicester petrophysicists, who study physical and chemical properties of solids (such as rocks and sediments) and liquids (water and gases) are joining the expedition. Dr Andrew McIntyre from the School of Geography, Geology and the Environment will work offshore with his Leicester colleagues Dr Erwan Le Ber, Dr Marisa Rydzy, and Dr Tayyaba Khurram, to provide scientific expertise and support to the expedition.

The expedition begins in May. A special platform, the liftboat ‘L/B Robert’ equipped with a small drilling rig, will be used to access the sediments below the ocean floor at up to three locations on the New England Shelf offshore from the coast of Massachusetts, USA. These locations are in relatively shallow water and were identified through numerous preliminary geoscientific investigations. The investigations, including retrieving sediment cores and water sampling, will extend down to a maximum depth of 550 meters below the ocean floor and will be examined by researchers from a range of disciplines and drawn from across the international scientific community. 

Dr McIntyre said: “Expedition 501 will be an exciting adventure to unravel the history of the sub-surface hydrogeology to understand why ancient, freshened water is locked up in the shelf sediments.

“During this expedition, I will be joint Petrophysics Staff Scientist together with Dr Le Ber. We oversee the collection of both core and downhole physical properties data. These data tell us about the mineralogy of the sediments and fluids within. The fluids are particularly interesting because we are interested in the freshness of the water and how old it is.

“This will be my third offshore expedition, and I will be offshore for at least 50 of the 90 days. For Expedition 501, the liftboat Robert will be our home and our workplace, yet it is only about 56 m in length, so about half a football pitch. This makes life onboard quite challenging as you don’t have much space. Despite this, you develop a strong team camaraderie, friendships and scientific collaborations. I am very much looking forward to sailing on this one!”

Â鶹APP has had a long-term involvement within scientific ocean drilling starting in the 1980s. Professor Sarah Davies, lead of the IODP3 group at Leicester and Head of the College of Science and Engineering at the University of Leicester, said: “The scientific community spends years planning these expeditions to address important scientific questions. Therefore I am very proud that the University of Leicester is a key part of a long-standing partnership with the British Geological Survey, MARUM (University of Bremen, Germany), and the University of Montpellier (France) who continue to work closely together to implement research expeditions for the international community and facilitate new discoveries. 

"We look forward to exploring this poorly understood offshore groundwater system where information from the expedition will support the future protection and sustainable management of this, and other, freshwater systems around the world.”

In 2023, Dr McIntyre, Dr Le Ber, and Dr Rydzy joined an expedition to investigate the ‘Hawai’ian Drowned Reefs’, which succeeded in obtaining a high-resolution continuous record of environmental data from shallow-water corals off the coast of Hawai’i (USA) by coring fossil coral reefs. In 2024, Dr Rydzy and Dr Le Ber joined an expedition to recover new samples of the fault zone of devastating 2011 Japan earthquake.

41 science team members from 13 nations (Australia, China, France, Germany, India, Italy, Japan, Netherlands, Portugal, Sweden, Switzerland, United Kingdom, USA) take part in the expedition that consists of two phases: offshore and onshore operations. Offshore Operations will take place between May and early August 2025. The entire science team will meet for the onshore work at the Bremen Core Repository, at MARUM – Center for Marine Environmental Sciences at the University of Bremen (Germany) in January 2026 to split, sample, and analyze the sediment cores and interpret the data collected.

The cores will be archived and made accessible for further scientific research for the scientific community after a one year-moratorium period following the onshore phase of the expedition. All expedition data will be open access and resulting outcomes published.