idw – Informationsdienst Wissenschaft
Nachrichten, Termine, Experten
Nachrichten, Termine, Experten
Start of an international expedition off the coast of New England
Freshwater under the Ocean – 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. Prof Karen Johannesson of University of Massachusetts Boston and Prof 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 May 19.
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 International 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 on the New England Shelf with the intention of understanding this offshore aquifer system.
Aim: Validate hypotheses about water origin
The key priority for researchers is to gain 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 existed approximately 450,000 and approximately 20,000 years ago.
Hydrogeologist Brandon Dugan: “We have anecdotal evidence of offshore freshened groundwater from samples and marine geophysical surveys. We have used this evidence to develop hypotheses on timing and mechanism of emplacement. It is exciting to use established scientific ocean drilling approaches with modern data analyses to provide direct tests of our hypotheses. Overall, this work offshore New England will help us better understand offshore freshened groundwater around the world.”
Environmental Geochemist Karen Johannesson: “To date, we know very little about the dynamics of these shoreline-crossing groundwater systems and the age of the water in these systems, and even less about their influence on cycling of nutrients and trace elements and their isotopes.”
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. Sediment cores and water samples will be taken down to a maximum depth of 550 meters below the ocean floor and will be examined by researchers from various disciplines drawn from across the international scientific community. The ECORD Science Operator team at MARUM has been helping to prepare the expedition for years and is now involved with mobile container laboratories at sea and later in Bremen.
High societal relevance: to better understand aquifers around the world
The team believes that the data acquired will help to better understand the processes that lead to the emplacement of freshwater lenses in offshore coastal plain sediments and why this freshened water is present. The findings will be relevant for the hydrogeology of the New England Shelf and for multiple similar settings elsewhere around the world.
The research is essential for a better understanding of the biogeochemical and elemental cycles in the continental shelf environment and will support a focus on the protection and sustainable management of offshore freshwater systems.
Part of the science team is Dr. Verena Heuer from MARUM – Center for Marine Environmental Sciences at the University of Bremen, invited geochemist for this expedition. The task of the geochemists is to characterize the quality of groundwater in order to draw conclusions on its age, its origin and its influence on element cycles. To this end, hundreds of interstitial water samples will be extracted from sediment cores, and a few additional samples will be retrieved during groundwater pump tests. “Good communication and careful development of a detailed sampling plan is essential, as we want to split and preserve ~15 mL of sample for more than 20 different analyses in twelve laboratories around the world”, explains Dr. Heuer, who leads the aquatic geochemistry science team. During this expedition, she is collaborating intensively with the ECORD Science Operator team members at MARUM to ensure that the precious samples can be utilized in the most efficient way.
The expedition aims to find answers to the following questions:
• How old is the freshened groundwater, and when was it emplaced?
• How much freshwater is there?
• How does the freshwater interact with seawater?
• What microbial communities are involved?
• What sources of carbon do microbes use?
• What is the general cycling of nutrients and energy in the shelf sediments?
• How might these freshwaters influence nutrient, carbon, and metal concentrations in seawater?
International approach
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 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 an onshore operations phase of the expedition. All expedition data will be open access and resulting outcomes published.
The expedition is conducted by the European Consortium for Ocean Research Drilling (ECORD) as part of the International Ocean Drilling Programme (IODP³), funded by IODP³ and the National Science Foundation (NSF). IODP³ is a publicly-funded international marine research program supported by 16 countries, which explores Earth's history and dynamics recorded in seafloor sediments and rocks, and monitors sub-seafloor environments. Through multiple platforms – a feature unique to IODP³ – scientists sample the deep biosphere and sub-seafloor ocean, environmental change, processes and effects, and solid Earth cycles and dynamics.
Dr. Verena Heuer
MARUM – Center for Marine Environmental Sciences
University of Bremen
Email: vheuer@marum.de
http://www.ecord.org/expedition501/ About the expeditio
http://iodp3.org/documents/expedition-501-scientific-prospectus/ - Scientific Prospectus
http://iodp3.org/about/ - About the international research collaboration
http://www.ecord.org/ - About the European part of the program
http://www.ecord.org/expeditions/msp/concept/ - Mission-Specific Platform expeditions
http://expedition501.wordpress.com/2025/02/19/faq1/Offshore - Frequently Asked Questions
Science and ECORD Science Operator Team and of the first rotation onboard liftboat L/B Robert. It wi ...
Jeremy Everest
Everest@ECORD_IODP3_NSF
Criteria of this press release:
Journalists, all interested persons
Chemistry, Environment / ecology, Geosciences, Oceanology / climate
transregional, national
Cooperation agreements, Research projects
English
Science and ECORD Science Operator Team and of the first rotation onboard liftboat L/B Robert. It wi ...
Jeremy Everest
Everest@ECORD_IODP3_NSF
You can combine search terms with and, or and/or not, e.g. Philo not logy.
You can use brackets to separate combinations from each other, e.g. (Philo not logy) or (Psycho and logy).
Coherent groups of words will be located as complete phrases if you put them into quotation marks, e.g. “Federal Republic of Germany”.
You can also use the advanced search without entering search terms. It will then follow the criteria you have selected (e.g. country or subject area).
If you have not selected any criteria in a given category, the entire category will be searched (e.g. all subject areas or all countries).
