The GEOTRACES Intermediate Data Product 2025 (IDP2025).

The GEOTRACES Intermediate Data Product 2025 (IDP2025) is the fourth release of publicly available data products from the international GEOTRACES programme and contains trace element and isotope (TEI) data reported before the end of 2024. The TEI data in the IDP2025 are quality controlled by careful assessment of intercalibration results and multi-laboratory data comparisons at crossover stations. The IDP2025 is a major new data release. Compared to IDP2021, IDP2025 improves data coverage significantly in all ocean basins. Overall, the new data product contains 16 new cruises, 721 new stations and 468,317 new data values. As an example, the number of dissolved Fe values has increased by 7463 to 23,912 in the IDP2025. IDP2025 also contains data for a large suite of biogeochemical parameters, as well as aerosol and rain data characterising atmospheric TEI sources and cryosphere TEI data from the Arctic. IDP2025 is comprised of five packages of digital data: (1) seawater discrete water sample data including TEIs as well as standard hydrographic parameters, (2) aerosol data, (3) precipitation data, (4) cryosphere data and (5) seawater sensor data. The digital data are available in ASCII, netCDF, and Ocean Data View collection formats, with data quality flags and 1-σ data error values where available. Metadata concerning data originators, analytical methods, and original publications related to the data are linked in an easily accessible way. IDP2025 introduces new parameters that reflect (1) different electrochemical methods for the measurement of dissolved trace metal ligand concentrations and binding constants, (2) extraction with or without pre-oxidation of the samples using UV exposure or hydrogen peroxide addition for Cu concentration and isotopic composition measurements, and (3) medium and small size classes of particulate TEIs. In the seawater discrete water sample dataset, the previously separate parameters with sampling suffixes BOTTLE, FISH, UWAY, PUMP, BOAT_PUMP, and SUBICE_PUMP were unified into single parameters. The new, unified parameters, such as Fe_D_CONC, now contain all measured values of the given TEI, irrespective of the sampling system. This makes using the IDP2025 data easier and ensures that data of easily overlooked specific sampling systems, such as FISH, are utilised. The GEOTRACES IDP2025 is released under the Creative Commons By Attribution (CC-BY) Licence 4.0 as described in the Fair Use Agreement.