American and Canadian scientists have discovered a secret garden, an extensive proliferation of blooming phytoplankton under the Arctic Ocean.
Phytoplankton is collections of unicellular that live in oceans; most of them simply drift in water currents. By photosynthesis they use sunlight, carbon dioxide and water to produce organic matter. They extract nearly as much carbon dioxide from the atmosphere as land plants and by doing so the play a vital role in regulating climate.
The scientists took part in the NASA expedition ICESCAPE, in the framework of which they examined the effect of climate change on the Arctic eco-systems on the northern and western shores of Alaska in the summer of 2010 and 2011. This is how they discovered the blooming phytoplankton under the ice of the sea the expanse of which has now reached 100 kilometres.
Ground-breaking discovery
The blooming of planktons has so far been only observed on the Arctic seas late in the summer when the process took place on the open seas through exposure to sun. The underwater garden, nevertheless, has proved to be much more extensive than the blooming phytoplankton colonies by the neighbouring open waters. “I have been conducting experiments for thirty years and based on my experience I would say that such a thing is impossible as so far we have assumed that sunlight can barely pass through the ice,” commented Kevin Arrigo, oceanographer at Stanford University.
Climate change, however, has changed the nature of the Arctic ice. The ice that had was thickened throughout years and which used to let only filtered light pass has disappeared at many places. The new ice that forms in winters is thinner and more transparent, that is, it allows more light to pass through. What’s more, warmer air melts its surface and darker patches collect and absorb light.
According to scientists more than half of the light passes through the ice.
When the ship broke the at places one-metre-thick ice and the scientists peeped into the depth with the help of their underwater cameras they observed an startling proliferation of phytoplankton. As a result of sunlight and the currents rich in organic nutrients from the Bering Sea the microorganisms thrived even in a depth of 50 metres.
Global warming means an increase in the average temperature of the Earth’s atmosphere and oceans. The largest temperature rise was caused by the increased emission of greenhouse gases in the middle of the 20th century, as a result of such activities as burning fossil fuels and deforestation.
