Carbon Fixation Potential of Macroalgae (Ulva Lactuca) Coupled with Anthropogenic Pollutants in Coastal Areas

Macroalgae are valuable for chemical raw material extraction, but their carbon sequestration capacity is not well studied. We investigated the effects of land-based pollutants (copper, lead, alcohols, and ketones) on Ulva lactuca growth and photosynthetic carbon sequestration in an offshore biosequestration system. Results show that Cu2+ concentrations (0.1 μmolL−1 to 0.2 μmolL−1) stimulate algal growth, while higher concentrations are toxic. Pb2+ consistently promotes growth across tested concentrations and maintains stable inorganic carbon uptake rates. Both ethanol and acetone, at appropriate concentrations (0.1 molL−1 to 0.5 molL−1), promote algal growth but inhibit it at higher thresholds, reducing RGR and inorganic carbon uptake. This study provides practical insights into macroalgae's carbon sequestration capacity under pollutant enrichment.