WOW!

Just yesterday I put forward my views on being curious. Well this article is a child of my curiosity about a particular something. It's other parent is some personal research that I had done on it.

Antarctica is popularly known as the White Continent, being totally covered in ice. Conditions are far from being habitable. But there are some people in the various research stations in there and also the seasonal visitors. It is also home to a large variety of fauna, penguins and seals dominating in population and whales catching up soon after. Flora limits itself primarily to the varieties of lichens and mosses. But it's not these species that caught my attention.

My father has been lucky enough to visit Antarctica and come back in good health. Firstly, it's an extremely costly affair. Secondly, through Ushuaia(Argentina), one has to cross the tempest of the Beagle Channel to go to Antarctica. That little notorious strip of water has a history of ships overturning and sinking in it. Thirdly, the day and night temperatures in Antarctica are well below freezing point is summer. Let's not even imagine a winter there, especially in it's perpetual darkness for almost 6 months! Nobody ventures out there in winter, and likewise, my dad visited it in summer, in the month of December(winter for northern hemisphere means summer for southern hemisphere).

I was going through the pictures he had managed to take and I made an interesting observation! The ice there had colours! Some were bright blue, coming from the inside, some green, and a few with brown and grey shades! My dad had no answer to this. But I needed one. So I did a lot of research on it. What I'll post now is a summary of what I have researched and concluded. This may be right, may be wrong because speculations are still on. One more thing is that whatever the reasons are, they are not mandatory explanations but possible ones rather. So here's the thing (in italics) :-

            Now it is definitely intriguing as to why icebergs appear to be differently coloured in spite of being formed from the same water cooled below freezing point! Well there are a couple of theories. One of them states that seawater is drawn deep underneath the ice shelves by the ocean currents and in the process, it becomes super-cooled. Under certain conditions, it may freeze at the base of the ice shelves. So we get two different sources of water: the one at the base of the shelves being sea water while the original ice shelves from fresh water. This seawater ice often has dissolved organic matter and minerals in them, causing to give the various textures. Weathering by winds and waters can cause further variance in textures.

            But what about icebergs that lay beyond the effect of ocean currents? Are the textures caused only due to oceanic waters freezing at the base under super-cooled conditions? Well the answer is no. The explanation for this phenomenon in icebergs lying beyond the reach of ocean currents is the melting of Antarctic ice itself! Before the icebergs break off, melting occurs. So the crevasses high on the Antarctic Plateau are filled with the melt water and then refreeze. This can possibly give the layer of blue within a white ice matrix.

            Another possible explanation says that the differing colours are due to the amount of trapped air in the icebergs. Different amount of air gets trapped with different layers of snowfall under different conditions. Further, air trapped can escape due to the pressure of the layers above. So, during snowfall under very cold conditions, more air gets trapped, resulting in a paler or white layer. The darker blue layers come from snowfall in relatively warmer, maybe even in wet conditions when little or no air is trapped.

            It is quite magical standing next to an iceberg when the sun is shining and glistening off the ice! The sun rays actually penetrates deep into the layers of the icebergs and get reflected off the inner surfaces giving a whole variety of effects and colours from white, through a range of vivid blue, making it all the more surreal! White light consists of a spectrum of varying wavelengths. Red colour has the maximum wavelength while violet has the least. Denser ice absorbs the longer wavelengths and reflects the shorter ones. Hence they appear blue to the human eye. White coloured ice instead scatters colours of all wavelengths at the boundaries between the ice and air bubbles trapped inside and hence, appears colourless. 

            The strips of other colours can be attributed to the sediments picked up by the ice sheets as it grinds downhill towards the sea. Sometimes the green colour maybe caused due to the presence of blue green algae in the waters.

So here are the various possible explanations of the textures that can be seen on the icebergs. I leave it to the discretion of the readers to debate the rightness or the wrongness of the explanations mentioned above. Feel free to comment. I would always like to know more on this for I believe there's a lot more to this. 

But being naive even for a little while, I close my eyes and imagine the ice on the White Continent. Only one word comes to my mind-"wow!" The fact figures will further amaze anybody! 

Yes, facts just add on to the amazement of  the perceptions of a naive mind. For me, it's pure imagination from what I have heard from my dad and from what I have seen in his pictures. I just can't wait to be there to see it with my own eyes!

Perhaps someday!