Ocean acidification can harm marine organisms that use calcium to build their shells. Researchers studied how a type of algae, Emiliania huxleyi, responds to acidification. They tested two methods: adding acid directly or increasing CO2 levels. Acid from HCl damaged the algae's growth and shell-building, but CO2 enrichment did not. The algae's photosynthesis was not affected, and it even increased slightly. Acid from HCl suppressed calcium uptake, but this improved with higher carbon levels. The algae produced more storage and shell-building materials with both acidification methods. In conclusion, Emiliania huxleyi can adapt positively to acidification through CO2 enrichment, but not just acidification.