A major international scientific effort has set sail to study freshened groundwater buried beneath the seafloor off the coast of Massachusetts. This water, first discovered in the 1960s, has long puzzled researchers due to its unexpected presence under the ocean. Expedition 501 “New England Shelf Hydrogeology” is the first to directly sample and analyze these offshore aquifers.
Davide Gamboa, researcher at CESAM and professor at the Department of Geosciences of the University of Aveiro, is the lead scientist of the sedimentology team on the expedition. At CESAM, he is part of the Research Cluster RC1 – Deep Sea, Ocean and Transitional Ecosystems, whose mission is to advance knowledge about marine ecosystems, including those of the deep sea and transitional zones, and their interactions with human activities.
Led by Prof. Karen Johannesson (University of Massachusetts Boston) and Prof. Brandon Dugan (Colorado School of Mines), the expedition brings together 41 scientists from 13 nations. The team began offshore operations in May 2025 aboard the L/B Robert, a specialized liftboat equipped with a drilling rig, which departed from Bridgeport, Connecticut on May 19.
Researchers aim to answer key questions: How old is this groundwater? How much is there? How did it get there? And how does it interact with seawater? Hypotheses suggest the water may have been emplaced during periods of low sea level or under ancient glaciers. The team will also investigate microbial communities and the role of these waters in nutrient and carbon cycling.
Sediment and water samples will be collected from depths up to 550 meters at three locations on the New England Shelf. These shallow marine sites were selected based on earlier geophysical studies. Offshore work will continue through early August, followed by onshore analysis in January 2026 at MARUM, University of Bremen, Germany.
The research is conducted by the European Consortium for Ocean Research Drilling (ECORD) under the International Ocean Drilling Programme (IODP³), with support from the US National Science Foundation (NSF). Findings will advance global knowledge of offshore aquifer systems and inform sustainable freshwater management.
All data and core samples will be made publicly available after a one-year moratorium.
More information:
Expedition Overview
Scientific Prospectus
FAQ
Full press release [here]
Photo: Everest@ECORD_IODP3_NSF – The L/B Robert, base for scientists until August.