Data set for ice nucleation by viruses and their potential for cloud glaciation

In order to effectively predict the formation of ice in clouds we need to know which subsets of aerosol particles are effective at nucleating ice, how they are distributed and where they are from. A large proportion of ice-nucleating particles (INPs) in many locations are likely of biological origin, and some INPs are extremely small being just tens of nanometers in size. The identity and sources of such INPs are not well characterized. Here, we show that several different types of virus particles can nucleate ice, with up to about one in twenty million virus particles able to nucleate ice at −20 °C. In terms of the impact on cloud glaciation, the ice-nucleating ability (the fraction which are ice nucleation active as a function of temperature) taken together with typical virus particle concentrations in the atmosphere lead to the conclusion that virus particles make a minor contribution to the atmospheric ice-nucleating particle population in the terrestrial influenced atmosphere. However, they cannot be ruled out as being important in the remote marine atmosphere. It is striking that virus particles have an ice-nucleating activity and further work should be done to explore other types of viruses for both their ice-nucleating potential and to understand the mechanism by which viruses nucleate ice.

为精准预测云层中冰的形成过程，我们需要明确哪些气溶胶粒子（aerosol particles）具备高效冰核化能力、这类粒子的分布特征及其来源。诸多区域内占比可观的冰核粒子（ice-nucleating particles, INPs）大概率源自生物源，且部分INPs尺度极小，仅为数十纳米。此类INPs的具体种类与来源尚未得到充分表征。本研究证实，多种不同类型的病毒粒子均可实现冰核化：在-20℃条件下，约每两千万个病毒粒子中便有一个可具备冰核活性。针对其对云冰晶化过程的影响，结合冰核化能力（即冰核活性粒子占比随温度的变化关系）与大气中典型病毒粒子浓度进行分析后可得出结论：在受陆地影响的大气环境中，病毒粒子对大气冰核粒子群体的贡献相对有限。但在偏远海洋大气环境中，不能排除病毒粒子发挥重要作用的可能。值得关注的是，病毒粒子具备冰核活性，未来需开展更多研究，一方面探索其他类型病毒的冰核化潜力，另一方面阐明病毒实现冰核化的具体机制。