The Colors of Icebergs. Why “The Colors of Icebergs”? Aren’t all icebergs white? Maybe with a bit of blue mixed in?
The answer is that different icebergs can exhibit dominant components of blue, green, yellow or black.*. Color depends on whether there is contained frozen seawater (yes it can freeze in Arctic regions), or minerals from a glacier bottom or the sea bottom, or algae. or the sea bottom, or algae. In particular (or should I say “in particulate”?) an emerald green color can derive from frozen sea water, minerals on the sea bottom, and/or algae.
The iceberg pictured in the Arctic album surfaced dramatically, perhaps 40-50 feet from our small Zodiak inflatable boat. I heard it, then turned my head and saw it, then felt the turbulence (then of course, began to photograph it). If if had been significantly larger, its wave could have capsized our little boat (into 32 F water, giving us less than 15 minutes to survive) Or, if it had come up directly beneath our inflatable, we would have almost surely met the same fate.
So it is rare to photograph a green iceberg, and even rarer to witness the birth of one. We had only a short time for photos as the sun was setting (during 23 hour days) behind mountains just to our southwest. So, a rare event to witness and to photograph.
*The NYTimes, May 4, 1993 reports sea captains' puzzlement over various colors for many, many years.
The best explanation I found, by far, was on the web in “ABC Science” by Anna Salleh; and a very recent piece in Scientific American, January 5, 2018