https://doi.pangaea.de/10.1594/PANGAEA.996253Ukpabi, NdubuisiNdubuisiUkpabi0000-0002-8535-9041Aarhus UniversitySeidenkrantz, Marit-SolveigMarit-SolveigSeidenkrantz0000-0002-1973-5969Aarhus UniversityPANGAEA2026CHI indexcoccolith assemblagesCoccolithophoresecological contrastsecological polarityHolocenenutrient contrastsalinity contraststratification–mixing dynamicsthermal contrastDEPTH, sediment/rockDepth, top/minDepth, bottom/maxAGECoccolithophore hydrographic indexLogarithmZ-scoreEcological sum indexHydrographic contrast indexCalcidiscus leptoporusCoccolithus pelagicusEmiliania huxleyiGephyrocapsa spp.Helicosphaera carteriPontosphaera discoporaPontosphaera japonicaSyracosphaera pulchraUmbilicosphaera spp.Braarudosphaera bigelowiiGravity corerDana12-11Dana (1981)2025-09-12T14:20:00Dataset10.1594/PANGAEA.9962632160 data pointstext/tab-separated-valuesCreative Commons Attribution 4.0 InternationalThis dataset presents the full suite of ecological component scores, contrast indices, and Coccolithophore Hydrographic Index (CHI) transformations calculated for each sample of core DA12 11/2 ST1 GC01. For every depth and corresponding calibrated age, the table reports warm water, cold water, high salinity, low salinity, oligotrophic, nutrient rich, stratified, and mixing ecological sum indices, each representing the cumulative abundance of taxa assigned to a given ecological affinity. These sums form the basis for the hydrographic contrast indices, computed as the difference between opposing ecological sums (e.g., thermal contrast = warm_sum − cold_sum; salinity contrast = highSal_sum − lowSal_sum; nutrient contrast = oligotrophic_sum − nutrient_sum; stratification/mixing contrast = stratified_sum − mixing_sum). The contrasts quantify the ecological polarity of each assemblage and serve as the input structure for the CHI calculation. CHI values were derived by combining all four contrasts into a single dimensionless hydrographic proxy, subsequently transformed through log₁₀ scaling, z score standardization, and tanh normalization to enhance distributional behaviour and comparability across samples. This table also includes raw species percentages for all identified coccolithophore taxa, enabling direct linkage between ecological composition and hydrographic state. Together, these parameters provide a detailed, sample by sample reconstruction of ecological structure and hydrographic variability throughout the Holocene.-20.7027361.60893Iceland Basin