This is a direct depth-profile chart, not a rendered 3D core: the left strip is a stratigraphic column and the right curve plots carbon density C directly against depth z, both driven by the same analytic solution used in the 3D version. Each parcel of sediment is buried under fresh material at the accretion rate w (cm/yr). Its organic carbon density decays as a first-order process, but the rate constant depends on whether the parcel sits above or below the oxic/anoxic boundary at depth dox:
dC/dt = -k(z)·C
k(z) = k_aer (fast, z above d_ox — oxygenated)
k(z) = k_anaer (slow, z below d_ox — waterlogged)
age a = z / w (time since deposition)
t_ox = d_ox / w (time spent in the oxic zone)
C(a) = C0·e^(-k_aer·a) if a ≤ t_ox
C(a) = C0·e^(-k_aer·t_ox)·e^(-k_anaer·(a-t_ox)) if a > t_ox
k_aer ≈ 0.05 yr⁻¹ and k_anaer ≈ 0.002 yr⁻¹ here — roughly a 25× slowdown once burial passes the water table, matching field evidence that waterlogged, low-oxygen mangrove mud preserves organic matter far better than aerated soils. Total carbon stock is the depth integral ∫C(z)dz over the visible core; burial efficiency compares that stock to the carbon that would remain with zero decay.
- Accretion rate — how fast new sediment (root debris, trapped mud) piles up; higher rates bury carbon past the oxic zone faster, before it can decompose.
- Organic carbon input — the carbon density of freshly deposited sediment, set by mangrove litterfall and root productivity.
- Oxic-zone depth — how deep oxygen penetrates before the anoxic, waterlogged zone begins; pneumatophores and tidal flushing control this in real marshes.
Real-world relevance: this burial-and-preservation mechanism is why mangrove soils hold some of the highest carbon densities of any ecosystem on Earth — often 500–1000+ Mg C/ha in the top metre, several times a typical tropical forest, mostly locked in soil rather than biomass.