Data for Chukchi Sea Ice and Primary Production

Arctic sea ice strongly influences climate and marine ecosystems, but its relationship with ocean productivity is not always direct. By analyzing chemical and biological indicators preserved in seafloor sediments, we reconstructed changes in sea ice and marine productivity in the central Chukchi Sea over the past ~8,000 years. Here we present a new multi-proxy sedimentary record from the central Chukchi Sea spanning the middle to late Holocene. We integrate IP₂₅, phytoplankton biomarkers, diatom assemblages, and biogenic silica to (i) reconstruct the millennial-scale evolution of sea-ice cover and primary productivity, (ii) evaluate the roles of Pacific Water inflow and summer insolation as boundary forcings, and (iii) assess the consistency and added sensitivity of the IP₂₅ signal relative to microfossil-based indicators. By explicitly examining the phase relationship between sea-ice variability and productivity, our study provides a pre-industrial benchmark and mechanistic constraints on how inflow-driven stratification and nutrient supply may shape future Arctic primary production and carbon cycling.