news & views into account. Furthermore, the authors There are two important limits to the coccolithophores to ocean acidification is a argue that a longer experiment would have study. Among-clone sorting cannot be case of overwhelming ecological importance, resulted in better-adapted populations. The disentangled from evolution in clonal and the study is a significant step forward in suggestion seems plausible; the multi-clone lineages. Furthermore, we have no idea using interdisciplinary approaches to better populations adapted more than the single- whether the extent of adaptation seen in the understand the ramifications of global change clone populations, indicating that even better single-clone population is representative or in the oceans. ❐ adapted variants are possible, but have yet to exceptional — only one of six clones was occur in the single-clone experiments. used for the single-clone experiments, and Sinéad Collins is at the Institute of Evolutionary Lohbeck et al. also show that this clone never became the most frequent in Biology, School of Biological Sciences, University coccolithophores can evolve as a result of the multi-clone populations. However, given of Edinburgh, The King’s Buildings, Edinburgh between-lineage sorting of existing variation the logistical challenges associated with the EH9 3JT, UK. and de novo mutations within a single lineage experimental evolution of marine microbes5, e-mail: [email protected] (Fig. 1). In the multi-clone populations, one a more complete experiment would have clone repeatedly outcompeted the others, been prohibitive. References 1. Westbroek, P., Young, J. R. & Linschooten, K. J. Eukaryot. and growth rates rose in the single-clone Lohbeck and colleagues show that Microbiol. 36, 368–373 (1989). populations. Thus, we can expect that future calcifying phytoplankton can adapt to high 2. Riebesell, U. et al. Nature 407, 364–367 (2000). coccolithophore populations will be shaped carbon dioxide levels. The experiment 3. Lohbeck, K. T., Riebesell, U. & Reusch, T. B. H. Nature Geosci. 5, 346–351 (2012). by a combination of species succession and uses, rather than advances, evolutionary 4. Elena, S. F. & Lenski, R. E. Nature Rev. Genet. 4, 457–469 (2003). adaptive evolution. theory, and that is fine: the response of 5. Collins, S. Biogeosci. 7, 2199–2202 (2010).

SHERRY ROWLAND Ozone and advocacy In 1973 I was invited to the Royal Swedish massive ozone loss below about 25 km over Academy to present some of my research Antarctica during spring — famously termed on stratospheric ozone. The atmospheric the ‘ozone hole’. Rowland played a key role in chemistry community was critically the explanation of these findings, pointing to reviewing the impact of nitric oxide the role of ice particles in the generation of emissions from supersonic aircraft on chlorine atoms and radicals from CFCs. stratospheric ozone at the time. Apart from the science, Rowland took Before my talk, Sherry Rowland sent the lead in the fight against the worldwide me a preprint of an article by himself and use of CFCs, often working against the Mario Molina, neither of whom I had heard interests of the chemical industry. In 1987, of. The article postulated that reactive his efforts paid off: the nations of the world chlorine atoms, generated by the photolysis agreed to stop using CFCs and signed the of industrially produced chlorofluorocarbons Montreal Protocol. Sherry Rowland became (CFCs), could destroy ozone in the forever one of the great environmental stratosphere. I immediately realised that heroes of our time. we had a potentially highly important issue But CFCs were not the only atmospheric on our hands: ozone loss by the action of chemical that Rowland took an active interest chlorine compounds. in. In the late 1970s, his research group SPL

I discussed the paper briefly during my © began to collect air samples from a variety talk, not knowing that a journalist from a of remote sites to study their chemical and Swedish newspaper, Svenska Dagbladet, After checking the significance of the climatic significance. The air was analysed was in the audience. She reported the missing reaction with our pocket calculators, for methane, as well as for halocarbons. This findings the following day, and the message we came to the conclusion that it did not methane monitoring continues to this day, reached Rowland, who was in Vienna on a matter much. and is the world’s longest-running remote sabbatical from his position as professor at In the coming years, Sherry Rowland methane analysis programme. Most recently, the University of California, Irvine. He and and Mario Molina showed that industrially Rowland was keen to sample air in the region his wife Joan decided to visit me. I was a produced CFCs are broken down by sunlight of the Deepwater Horizon oil spill in the Gulf good host, and took them on a walking tour when they enter the stratosphere, yielding of Mexico. of some of the famous places in Stockholm, chlorine atoms that play a very important We will always remember Sherry such as the old town. I heard only later that role in ozone depletion. This was their Rowland with respect and admiration, and I they were exhausted. great discovery. am grateful for having known him. During the same visit, Rowland gave According to their original work, most a seminar about his new finding. In the chlorine atoms would be generated, and PAUL CRUTZEN subsequent discussion, it occurred to me most ozone destroyed, at altitudes above Department of Atmospheric Chemistry, the that he might have neglected an important about 30 km. So it was a big surprise Max Planck Institute for Chemistry, reaction. A spirited argument ensued, when, in 1985, Joe Farman of the British PO Box 3060, D-55020 Mainz, Germany. following which neither of us could sleep. Antarctic Survey and colleagues reported e-mail: [email protected]

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