Water covers 70 per cent of the earth’s surface and is the solvent of life. The chemical properties of pure water however, are universal, defining, and unchanging. What then gives different natural water courses their unique identities, exists within water, and in-between the spaces of its polar molecules. This work explores these defining elemental signatures through a process that colorimetrically reveals one of the most important of these, the concentration of hydrogen ions present. When a pH indicator is added to the water samples, its colour changes according to concentration of hydrogen ions, and thus reveals this otherwise invisible yet defining chemical signature. The nine water samples in the image here range from those taken from Surrey’s acidic and tannic marsh waters (red), through neutral river waters (green), to the alkaline and clear waters of Hampshire’s famous chalk rivers (blue).
Of note here, there is also one seawater sample present which at the moment is distinctly alkaline (blue). However, with the oceanic acidification brought on by elevated atmospheric carbon dioxide concentration this water will become more acidic and its influence on sea-life and the pH indicator will inevitably change.