Early Diagenesis in Sediments of the Venice Lagoon (Italy) and Its Relationship to Hypoxia

A critical link between sediment diagenesis and hypoxia in the Venice Lagoon has been identified, with intense diagenetic activity potentially triggering and sustaining low-oxygen conditions during summer months. The study, spanning three years (2015–2017), found that high-intensity diagenetic zones could deplete oxygen to hypoxic levels within 5–18 days under stagnant conditions, a process exacerbated by climate-driven heatwaves. Sediments were categorized into intense and moderate diagenesis groups based on metrics like dissolved inorganic carbon production (2.8 vs. 1.0 mmol m⁻² d⁻¹) and sulfate consumption (1.6 vs. 0.4 mmol m⁻² d⁻¹). Porewater sulfide accumulation near the sediment-water interface further underscored the role of sediments in oxygen depletion, with implications for lagoon health under changing climate scenarios.

Brigolin, D., Rabouille, C., Demasy, C., Bombled, B., Monvoisin, G., & Pastres, R. (2021). Early Diagenesis in Sediments of the Venice Lagoon (Italy) and Its Relationship to Hypoxia. Frontiers in Marine Science, 7. https://doi.org/10.3389/fmars.2020.575547