Aquatic systems play a salient role in the complex processes of energy and matter exchange between the geosphere and the atmosphere. For example, reactions taking place in cloud water droplets can substantially alter the atmospheric budget and chemistry of trace gases; pollution induced weathering reactions at water/soil interfaces can affect the availability of nutrients and increase the concentration of potentially toxic metals in groundwaters. Moreover, the inextricable links between the water cycle, the geosphere and the atmosphere ensure that apparently localized environmental problems...