Italiano 
English The sun's rays caress every surface of the Earth, make snow sparkle, and give depth to forests. They do the same with the sea, shimmering on the crests of the waves. Water, which is not solid, allows light to penetrate between its particles, among currents and the various layers. Beyond 180 meters in depth, however, light fades and gives way to shadows, darkness, blackness. That the colors we perceive in the world are connected to the degree of light is easy to say; in the case of water, its molecules are able to absorb all the frequencies of the electromagnetic waves that make up light, except for blue, which is therefore reflected outward and appears to our eyes.
A new variable enters the scene: the presence of plankton. We can think of phytoplankton as a mass of plants, and what is most evident is that trees, grass, flowers, and forests shape our planet with their range of greens. What, then, is the effect of all this vegetation in a blue universe? (Together, of course, with types of seabeds, chemical composition of sediments, degree of water clarity, currents, and angle of the rays: all elements that generate different absorption and reflection of light.)
The effect is that water changes color based on the concentration of chlorophyll, the bright green pigment that allows plants to perform photosynthesis, absorbing the nutrients contained in carbon dioxide through sunlight. They absorb solar energy, add water and carbon dioxide, and produce sugar. In doing so, they release oxygen (a waste product). And so, in Costa Smeralda the waters are a deep, brilliant green; in Indonesia, among the Raja Ampat islands, a light turquoise; or, again, they tend toward gray in the Arabian Sea along the coasts of Kerala, in India. On the other hand, since plankton are wandering drifters—they move and their distribution varies throughout the day, the hours, the seasons—they carry with them the mechanisms of oxygen production: studying the degree of oxygenation of waters therefore proves particularly complex for scientists.
l'acqua riesce sempre a farsi strada
e l'oceano ancora una volta dimostra che vince facilmente alla lunga contro le montagne giganti
