Scenario-based productivity and potential long-term carbon retention for mesophotic kelp habitats in the Southwestern Atlantic

This Zenodo repository accompanies the manuscript “Scenario-based productivity and potential long-term carbon retention for mesophotic kelp habitats in the Southwestern Atlantic” and contains the complete set of supplementary materials and analytical resources required to reproduce and evaluate the study. The research examines the environmentally supported 45–70 m depth domain of the endemic and endangered Brazilian kelp Laminaria abyssalis along the Southwestern Atlantic continental shelf and evaluates the consequences of spatial uncertainty, sparse biomass observations, literature-derived productivity analogues, assumed habitat occupancy, and alternative long-term carbon-retention fractions. The repository includes the revised manuscript; Supplementary Figures S1–S6, comprising in situ Dropcam imagery of the mesophotic L. abyssalis habitat, the uncropped present-day ensemble species-distribution-model input, the historical Laminaria NPP literature and transferability audit, the complete inverse-distance-weighting validation and falsification analysis, the spatial-support sensitivity audit, and the full deterministic NPP-transferability and 100-year retained-carbon scenario envelope; and Supplementary Tables S1a–S6, containing the biomass observations and raster-cell assignments, literature-derived biomass metadata, complete IDW cross-validation diagnostics, spatial-domain and bathymetric-support summaries, productivity-literature coverage and study-group statistics, and the full set of occupancy × retention × time-horizon scenarios propagated across the empirical lower, central, and upper NPP anchors. The repository also provides the R analysis pipeline, derived spatial layers and rasters used in the analyses, tabular outputs, reproducibility metadata, package and session information, and supporting documentation needed to trace the analytical workflow. Importantly, the biomass interpolation is retained only as a diagnostic because positive-power IDW models did not outperform the non-spatial leave-one-out benchmark, and no interpolated biomass surface was used to calculate productivity or carbon retention. The reported productivity and retained-carbon values are therefore explicitly scenario-based, assumption-dependent screening estimates, not measurements of kelp occupancy, carbon export, burial, permanence, sequestration, climate mitigation, or carbon-credit potential. The archived materials are intended to provide full analytical transparency, facilitate independent reproduction of the results, and support future field validation of L. abyssalis occupancy, productivity, detrital transport, burial, and long-term carbon fate.