The TREC expedition started in April 2023 and is expected to last until end of June 2024. During that time, the researchers will be gathering biological samples and environmental data along the European coastline at more than 120 land-sea transects. In selected sites, time-series measurements will be performed to account for annual changes.

The expedition combines ocean exploration, conducted by the Tara Ocean Foundation and Tara Oceans Consortium, with parallel sampling of soil, sediment, shallow water, and selected model organisms in various habitats, supported by EMBL’s land-based mobile services and local marine research institutions. Organismal diversity is being studied across scales, from viruses, bacteria, and protists to multicellular groups such as algae and animals. Analysis involves various meta- and single-cell omics as well as barcoding techniques that will be combined with innovative microscopy pipelines including automated imaging and electron microscopy. This allows unprecedented detail in associating molecular and morphological data at the single-organism and single-cell level. Besides standard oceanographic metadata, special emphasis is put on detecting metabolites as well as physical and chemical (i.e. inorganic and organic pollutants such as metals, pesticides, hormones, and antibiotics) characterisation of the sampled habitats, providing the environmental framework to the biodiversity and adaptation analyses.

Overall, the expedition aims to conduct systematic, standardised, and integrated sampling with multimodal environmental metadata acquisition. This integrated profiling across environmental and man-made gradients of micro- and macroscopic life will enable us to obtain a first of the kind, pan-European census of European coastal ecosystems.