The Modern Ocean Sediment Archive and Inventory of Carbon (MOSAIC): version 2.0

Abstract. Marine sediments play a crucial role in the global carbon cycle by acting as the ultimate sink of both terrestrial and marine organic carbon. To understand the spatiotemporal variability in the content, sources and dynamics of organic carbon in marine sediments, a curated and harmonized database of organic carbon and associated parameters is needed, which has prompted the development of the Modern Ocean Sediment Archive and Inventory of Carbon (MOSAIC) database. We present here MOSAIC version 2.0, which has expanded the spatiotemporal coverage of the original database by ~400 %, and now holds data from more than 17000 individual sediment cores from different continental margins on a global scale. Additional variables have also been incorporated into MOSAIC v.2.0 that are crucial to interpret the distribution of the quantity, origin and age of organic carbon in marine sediments globally. Sedimentological parameters (e.g., grain size fractions, mineral surface area) help understand the effect of hydrodynamic sorting and mineral protection in the distribution of organic carbon, while molecular biomarker signatures (e.g., lignins phenols, fatty acids, alkanes) can constrain the origin of organic matter with a greater level of specificity. MOSAIC v.2.0 also stores data from analyses performed on specific sediment and molecular fractions, which provide further insight of the processes that affect the degradation and ageing of organic carbon in marine sediments. While data included within MOSAIC is not exhaustive, it is continuously expanding and version control will allow users to benefit from updated versions while ensuring reproducibility of their findings.