Fig. 3: Relationships between environmental variables and paleogenetic data of primary producers, and their modeled impact on atmospheric CO2 across time.
From: Carbon drawdown by algal blooms during Antarctic Cold Reversal from sedimentary ancient DNA
a, The piecewise structural equation model (SEM) illustrates the relationship between environmental parameters as temperature and sea ice, and paleogenetic data of major primary producers over time. Arrow direction indicates assumed causality; standardized path coefficients (β) denote the strength and direction (positive/negative) of effects. Significance is marked by asterisks (see legend). Model fit: Fisher’s C = 6.80, P = 0.87. b, Seasonal sea-ice extent (SSIE; 1012 km2) and modelled impact of average NPP of different primary producers, combined with varying flux efficiencies (30%, 50%, 70%) from the atmosphere to surface waters, on global atmospheric carbon dioxide (CO2atm) concentrations (ppmv) before, during and after the ACR. Left panel: cumulative NPP impact during and after the ACR; right panel: before the ACR. Data are shown as medians with shading indicating median ± standard deviation. Hypotheses attributing carbon drawdown to any single taxon (colour-coded as ‘rejected’) were tested via two-sided paired t-tests with no correction for multiple testing required.
