Passive water harvesting by desert plants and animals: lessons from nature.

Fresh water sustains human life and is vital for human health. For some of the poorest countries, 1 in 10 people do not have access to safe and easily accessible water sources. Water consumption by man continues to grow with an increasing population. The current supply of fresh water needs to be supplemented to meet future needs. Living nature provides many lessons for water harvesting. It has evolved species which can survive in the most arid regions of the world by passively collecting water from fog and condensation of water vapour in the night. Before the collected water evaporates, species have mechanisms to transport water for storage or consumption. These species possess unique chemistry and structures on or within the body for collection and transport of water. Among the high diversity of species surviving in deserts, only a handful of species have been studied. Based on lessons from nature, bioinspired water harvesters can be designed. In this paper, an overview of various desert plants and animals is given and known water harvesting mechanisms of some are presented. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology (part 3)'.