Ocean acidification, compounding anthropogenic stressors and marine water chemistry: evidence, regime-shift risk and implications for marine life

Analysis scripts and derived data products behind the figures and numerical claims of Dryden & Duncan, "Ocean acidification, compounding anthropogenic stressors and marine water chemistry: evidence, regime-shift risk and implications for marine life". Contents: the winter aragonite threshold classification for all three zonation schemes; the same pipeline restricted to the polar and subpolar zone; the MODIS-Aqua equatorial Atlantic chlorophyll trend test; the figure build scripts; the derived 1-degree winter saturation and trend grids; the PyCO2SYS recomputation of aragonite saturation at the study sites with its per-point uncertainty; and the independent verification block. Primary datasets are not redistributed. OceanSODA-ETHZ v2025, SPOTS, GLODAP, CODAP-NA, World Ocean Atlas 2023 and the MODIS-Aqua ocean-colour products are public, carry their own DOIs, and are listed in README.md with the accessions needed to obtain them. Each script run against the original file reproduces the published values exactly. Expected outputs are tabulated in README.md so that any discrepancy is immediately visible. The polar-zone script deliberately reports the measured present state and no projection; the reason, a coverage artefact caused by seasonal ice in the trend mask, is documented in both the script header and the paper's Methods.