These awesomely eerie images come courtesy of photographer Franco Banfi. Banfi accompanied his diving partner, Alexander, on an expedition under the White Sea off of Russia's northwest coast. The duo ventured beneath layers of ice in near freezing water to explore the unique properties of the White Sea's ecosystem.
The uncanny greenish hue Banfi shares in this series comes from an organic substance called humus that's found in soil when plant or animal matter decays. The color of the water in this area varies depending on how much humus has washed into the water at any given time. Oh yeah, And those "ice boulders" you see above Alexander? They had to actually smash some of the frozen surface so that they could dive underneath. That's pretty badass.
View Banfi's work in the gallery to see more of this curious underwater phenomenon.