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An analysis of 24 coral reef viromes challenges the view that lytic phage are believed to predominate when the density of their hosts increase and shows instead that lysogeny is more important at high host densities; the authors also show that this model is consistent with predator–prey dynamics in a range of other ecosystems, such as animal-associated, sediment and soil systems.

Line shape spectroscopy is a valuable tool both for diagnostic purposes, and for understanding the basic atomic processes in the boundary region of magnetically confined fusion plasmas. We report on the present state of a versatile line shape model including Stark, Zeeman and Doppler broadening for an arbitrary emitter in the divertor or other edge plasmas. Several examples of temperature or density diagnostics based on the use of this model are presented for neutral and ionized carbon, and for hydrogen isotopes. In the case of the Dα line, fitting the model to the experimental spectra involves the determination of several parameters and we have thus used an efficient fitting technique based on a genetic algorithm. The results of this analysis, suggesting the existence of a population of neutrals of several hundreds of electronvolts, demand a more detailed study of the line wings. With the help of a simple model, we show that this part of the spectrum might indeed be sensitive to the turbulent fluctuations ubiquitous in edge plasmas.

Passive spectroscopy of the Dα line emission is used for the investigation of the Tore-Supra edge plasma in front of a neutralizer plate of the Ergodic Divertor. Two kinds of spectra are observed: symmetric and asymmetric. Symmetric spectra are fitted considering two isotropic populations of deuterium representing the main neutral production mechanisms. The fit of the asymmetric spectra, requires the addition of an anisotropic population resulting from the reflection of ions as neutrals on the V-shaped notches of the neutralizer plate and the inclusion of the relaxation of the deuterium populations through elastic collisions with the plasma ions.

Nature 531, 466–470 (2016); doi:10.1038/nature17193 In this Article, the ‘Predator–prey modelling’ section of the Methods shows Lotka–Volterra equations. Although these equations are meant to present a basic Lotka–Volterra model, the term ‘N/K’ in the second equation was inadvertently introduced during proofing, which makes the equations reflect the Piggyback-the-Winner model rather than basic Lotka–Volterra.