Deep-sea ecosystems on brink of collapse as ocean acidification breaches safety thresholds

Recent studies show that global ocean acidification has exceeded the “planetary boundary” – surface seawater aragonite saturation has dropped by 20% compared to pre-industrial times, and 60% of deeper seawater (below 200 meters) has exceeded the acidification level. Deep-sea coral reefs, shellfish and other calcifying organisms face an existential crisis, for example, oyster shells are dissolving at an accelerated rate and larval survival is declining. Coral bleaching and acidification in tropical waters have formed a vicious cycle, with coral reef cover in the Philippines, Australia, and other countries declining by more than 60% from 1970 levels. Scientists have warned that if urgent measures are not taken to reduce emissions, the pH value of the oceans may drop by 0.39 units by 2100, completely changing the structure of marine ecosystems.