Further evidence that increased acidity of sea water could be bad news for the world’s coral reefs. In Papua New Guinea carbon dioxide is bubbling into the water on the slopes of a dormant volcano. This is making the water slightly more acidic around the vents, and is allowing researchers to examine the effects on marine life at different levels of acidity. Acidity is important as it reduces the ability of coral and marine animals to form hard structures such as shells.
Seawater typically has a PH of 8.1. In an area of the study site that had a PH of 7.7 reef development apparently stopped. Instead, seagrass covered the seabed, but even this lacked the hard shelled snails that normally live on their fronds. Where the PH was slightly higher – 7.8, reefs still formed, but were dominated by one particular genus, the Porites (pictured here thanks to Wikipedia). Unfortunately these don’t have the branches that can shelter fish and other marine creatures, that many other species of coral do have.
This is particularly worrying as the Intergovernmental Panel on Climate Change are projecting that by the turn of the century the ocean’s PH may have fallen to 7.8.
Is this the future for the world’s coral reefs?
You can read more detail on the BBC’s website from where the first and third photo were taken.