A new study found the answer to the peculiar green ice that has been spotted at the Arctic. It seems that global warming provided the conditions which allowed massive blooms of phytoplankton to grow under the Arctic sea ice. More blooms might continue growing below the ice, which would shatter the equilibrium of the food chain in the ecosystem.
Global warming caused the occurrence of green ice
So far, phytoplankton has not been able to grow under sea ice. The ice layer was too thick and it reflected most of the light back to where it came from. Thus, it could not reach any plants growing below. This is where global warming acted.
Due to the constantly growing temperatures, the sea ice at the Arctic became thinner. Thus, light slowly started reaching more and more of the water residing under the ice. Also, dark puddles of water, called melt ponds, started forming on the surface of the ice. This made the surface reflect less light than before.
Therefore, a thinner layer of sea ice at the Arctic, and global warming in general, might be the answer to the mystery of the green ice. More details are given in the research published in the journal Science Advances.
Increasing number of blooms over the last twenty years
Researchers wondered how much light reached the water, now that the ice was thinner and the melt ponds were thicker. They discovered that the situation shifted completely. The main author of the study, Harvard professor Chris Horvat, explained what happened.
Twenty years ago, there was almost no possibility for plankton to grow below the sea ice. Only three or four percent of the entire Arctic ice surface could allow light to pass and plankton to grow. Now, the ice has gotten so thin that the areas with green ice are so vast that the phytoplankton blooms are overflowing. Around 30 percent of the ice surface allows such blooms during the summer months.
It seems that the melt ponds play an important role in the growing of phytoplankton. However, their presence would not have been enough if the thickness of the ice had not reached worryingly low levels. While this form of life found a way to thrive, thousands of others might be affected by the disturbance in their Arctic ecosystem.
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