• We mistakenly reported that all 59 people who received a new treatment for their inoperable brain cancer had died (4 October, p 16). We are pleased to report that several patients in the trial by Transmolecular of Cambridge, Massachusetts, are still alive.
• We said “marine organisms use dissolved CO2 in the ocean to build external skeletons and calcium carbonate shells. After death, these sink to the seabed and over time form new carbon-rich rock. The rate of this process increases if atmospheric CO2 rises, causing an increased drawdown of CO2 into the ocean” (27 September, p 34). In fact, the formation of calcium carbonate releases CO2 into seawater. Only the formation of sediments containing organic matter removes CO2.
• We apologise for misspelling the name of Habibollah Razmi of the University of Qom, Iran. (1 November, p 16).
