Oceans become acidic when they absorb CO2 from the atmosphere. Once dissolved, the gas reacts with carbonate to form bicarbonate, stripping seawater of the compound that many organisms (coral, shrimp, crabs) need to build their shells or skeletons.
Bronte Tilbrook of CSIRO ... measured the concentration of aragonite (calcium carbonate) ... at over 200 locations on an Australian reef. Models suggest that if seawater becomes too low in aragonite, organisms with aragonite shells will dissolve. Studies in the Red Sea have found that some species of coral start to dissolve at an aragonite concentration of 2.8.
Almost every bit of water in this Australian sample was below 3.5. Depite suboptimal conditions, Tilbrook found little evidence that coral had reached a critical point. "They are still growing."
This could either mean that corals are more resilient than we thought, or it could mean that the corals are on a knife-edge of survival.
Polistra was named after the original townsite of Manhattan (the one in Kansas). When I was growing up in Manhattan, I spent a lot of time exploring by foot, bike, and car. I discovered the ruins of an old mill along Wildcat Creek, and decided (inaccurately) that it was the remains of the original site of Polistra. Accurate or not, I've always liked the name, with its echoes of Poland (an under-appreciated friend of freedom) and stars. ==== The title icon is explained here. ==== Switchover: This 2007 entry marks a sharp change in worldview from neocon to pure populist. ===== The long illustrated story of Polistra's Dream is a time-travel fable, attempting to answer the dangerous revision of New Deal history propagated by Amity Shlaes. The Dream has 8 episodes, linked in a chain from the first. This entry explains the Shlaes connection.