Acidic oceans threaten fish

Acidic oceans threaten fish

Ocean acidification — caused by climate change — looks likely to damage crucial fish stocks. Two studies published today in Nature Climate Change reveal that high carbon dioxide concentrations can cause death¹ and organ damage² in very young fish.

The work challenges the belief that fish, unlike organisms with shells or exoskeletons made of calcium carbonate, will be safe as marine CO₂ levels rise.

Oceans act like carbon sponges, drawing CO₂ from the atmosphere into the water. As the CO₂ mixes with the water, it forms carbonic acid, making the water more acidic. The drop in pH removes calcite and aragonite — carbonate minerals essential for skeleton and shell formation — from the marine environment.

This can mean that corals, algae, shellfish and molluscs have difficulty forming skeletons and shells or that their shells become pitted and dissolve. Read More