Surface kelp fixes CO₂ into biomass by logistic growth toward a light/nutrient-limited carrying capacity:
dB/dt = r·B·(1 − B/K)
Periodically the raft is harvested and pressed into ballasted bundles that sink through the water column. Whether that fixed carbon counts as removal depends on how much organic matter survives the trip — governed by the Martin curve, the same power law oceanographers use for the biological carbon pump's particle flux:
F(z) = F(z₀)·(z / z₀)^(−b_eff), z₀ ≈ 100 m, b_eff = b / ballast
This 2D view splits the water column into two linked diagrams instead of a 3D camera scene: a depth cross-section on the left (bundles fall straight down through shaded remineralization bands) and a live Martin phase plot on the right, which plots the exact analytic decay curve F/F₀ vs. depth for the current effective exponent and drops a dot onto it for every bundle currently sinking — so you can see numerically, not just visually, that each bundle's colour/size in the cross-section matches its position on the analytic curve. The exponent is scaled by sink speed (b_eff = b / ballast) so a bundle's residence time in the bacteria-rich shallow layer — not just its final depth — determines how much carbon survives.
- Growth rate — sets how fast the raft's biomass (and CO₂ drawn into it) accumulates.
- Harvest interval — how often grown biomass is cut and dropped as a sinking bundle.
- Ballast weight — sink speed; faster sinking shortens residence time in the shallow layer, softening the effective decay exponent and raising the verified fraction.
- Remineralization intensity — the base Martin exponent b; higher values return more carbon to the water before it reaches depth.
Mass is converted from carbon to CO₂ using the 44/12 stoichiometric ratio (mass of CO₂ per mass of C).