Our planet earth is made up of a myriad of landscapes from lush green areas to barren deserts. One of the most beautiful sites that humans can experience are rivers of ice, or rather glaciers. Most of the world’s glacial ice is typically found in Antarctica or Greenland but glaciers can also be found on every continent.
Glaciers form in places where more snow piles up each year than melts. Glacial ice looks different from the ice cubes in your fridge, as it is so dense that it absorbs every other colour of the rainbow except blue, which is what we see. Its crystalline structure strongly scatters blue light, which is why the ice appears almost turquoise. The ice found on glaciers takes a very long time to form and is extremely compact. When new snow falls, it goes through the same process and buries the previous layer, making the snow even more compressed.
Like everything on earth, glacier ice flows because of gravity. As the glacier moves down the valley, it moulds itself to the land but also moulds the land. While glaciers do not even seem to be moving at all, the various parts of a glacier move at different speeds. The middle part with flowing ice moves faster than the bottom part, which grinds slowly along its rocky bed.
The ice on the top layer of the ice is brittle due to the difference in speed of the moving ice causing a lot of tension. These cracks, called crevasses can be found in the top 50 metres of the glacier and can be very dangerous for people walking on them as they tend to open quickly and be very deep. Ice is slippery, so crampons are needed to walk on glacial ice. Crampons have metal spikes and are added onto footwear in order to grip on ice.
Glaciers play an important role and provide us humans with many useful resources, such as fertile soil for growing food and a source of freshwater to ensure our survival, while the deposits of sand and gravel are used in concrete and asphalt. Besides being one of the world’s wonders, scientists study their geological processes for information of how our world was a long time ago. They give us a sneak preview of how the atmosphere was and the kind of fauna that lived thousands of years ago that has been preserved in ice. It is of no surprise that humans find glaciers so fascinating and are so curious to learn more.
Danielle Martine Farrugia is a PhD student and science communicator at the Department of Physics, Faculty of Science, University of Malta. She is a Science Communication lecturer, hosts Radio Mocha Malta and runs Malta Café Scientifique.
Did you know?
• 75% of the world’s freshwater is stored in glaciers.
• Climates with plenty of snow, like Alaska, have glaciers that flow all the way down to sea level that carve fjords and create icebergs.
• Ice calving is a process of how the iceberg breaks off from the glacier or an ice shelf.
• Moraine refers to the deposits of rock, dirt and gravel left on the sides of the glacier.
• Ice crawlers, Grylloblattids are primitive insects that only live in cold and extreme habitats such as glaciers or ice caves and cannot survive in warm temperatures, not even the touch of a human hand.
For more trivia, see: www.um.edu.mt/think
• Earlier this year the Thwaites Glacier Offshore Research (THOR) science team members embarked on a two-month cruise to the Amundsen Sea in Antarctica. The team is on a mission to collect sediment cores from Thwaites Glacier’s seafloor, together with ocean-floor sediments deposited where the current ice shelf is attached to the seafloor. These contain records of changes taking place in the glacier and the adjacent ocean. Researchers will also be able to view past topography of the seafloor in relation to the current ocean circulation near the Thwaites Glacier. Together with the information gathered from this cruise and another one in 2021, researchers will be better equipped to assess the glacier’s current and future stability.
• The Halley Bay penguin colony was the second largest in the world, with numbers varying each year between 14,000 and 25,000. However, researchers from British Antarctic Survey (BAS) found that the emperor penguins in the Weddell sea have failed to raise chicks for the last three years. The failure to raise chicks is linked with changes in the local sea-ice conditions. In order for emperor penguins to breed, they need stable sea-ice that must last from April upon their arrival, until December when their chicks fledge. In 2016, the sea-ice broke up in October, before the chicks could fledge, and this was repeated again for the next two consecutive years.
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