Polar ice melts and as this happens, the light conditions of the water column beneath it change. The color of rays reaching the depths changes and this affects all life in the ocean.
Light and ice
The melting of Arctic ice as a result of climate change may have rather unexpected consequences related to the light that passes through it. This conclusion was reached by an international team of scientists in a study whose results were recently published in the journal Nature Communications.
Arctic ice is large chunks of water in a solid state. They are lighter than salty ocean water, so they can swim, but are mostly submerged in it. At the same time, the ice is quite transparent. Of course, it absorbs a significant part of the sun’s rays, and some other part is delayed, but in general a lot of radiation passes through it.
So what would change if the ice over the polar seas melted? At first glance, nothing. The water is clear and the ice is clear, so what’s the difference? It might even get better. Because the surface of water does not reflect rays as much as the surface of ice. Therefore, the ocean will be brighter.
Change in water color
And now, a new study shows that’s not the case at all. The fact is that although ice reflects and refracts light more strongly than water, it absorbs different wavelengths more weakly and evenly. That’s why it looks transparently white in contrast to the blue ocean water.
And all because in liquid water its molecules fluctuate strongly unlike those in the nodes of the crystal lattice. And this is what leads to more scattering of certain wavelengths, primarily green and red wavelengths.
Therefore, according to the study authors, if Antarctic ice melts, its submerged portion will be replaced by liquid. Which means the color of the light that comes through it to the depths will change. It’s going to be more blue.
Impact on algae
Antarctic waters are home to a huge amount of microscopic algae. They exist because of photosynthesis. And in fact, it is not one, but a set of many diverse biochemical processes.
In fact, different algae get their energy from light of different wavelengths. And those that now live under the Antarctic ice are adapted to the light we see on the surface. The ice acts as a kind of window there.
But if it melts, those algae that get their energy from the bluer light will have an advantage. And all this phytoplankton, in turn, is the basis of food chains throughout the ocean and how all these changes will affect commercial fish populations is extremely difficult to predict.
According to phys.org
