What is an Ice Shelf?
- An ice shelf is a floating mass of glacial ice, fed from land by tributary glaciers, and extending over the sea above an ice shelf cavity.
- Key Ice Sheets:
- Antarctica and Greenland Ice Sheets hold two-thirds of Earth’s freshwater.
- The West Antarctic Ice Sheet is one of the largest.
- Role in Sea Level Changes:
- When ice sheets gain mass, global sea levels fall.
- When ice sheets lose mass, global sea levels rise.
Scientific discoveries under George VI Ice Shelf:
- Expedition: Conducted as part of Challenger 150, a UNESCO-endorsed global deep-sea research initiative.
- Remotely Operated Vehicle (ROV) SuBastian explored the seabed 1,300 meters deep.
- Key findings:
- Diverse ecosystem: Found icefish, giant sea spiders, corals, sponges, and octopi.
- New species: Scientists believe they discovered previously unknown marine species.
- Jellyfish discovery: A giant phantom jelly was recorded, growing up to a meter wide.
- Unusual nutrient supply: Despite being cut off from surface nutrients for centuries, life thrives—possibly due to ocean currents or glacial melt water transporting essential nutrients.
About George VI Ice Shelf:
- Location: Lies between Alexander Island and the Antarctic Peninsula.
- Size: Covers 24,000 sq. km, making it the second-largest ice shelf in the region.
- Ice flow: Receives ice from both the Antarctic Peninsula and Alexander Island.
- Unlike most ice shelves, it is laterally constrained (trapped between landmasses) instead of freely flowing into the ocean.
- It blocks epishelf lakes (trapped freshwater bodies between ice shelves and land).
- Situated at the -9°C mean annual air temperature isotherm, a critical threshold beyond which ice shelves are prone to collapse.
- Susceptible to melting from both atmospheric warming and warm ocean currents.
