Description

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Context

The discovery of thriving marine ecosystems beneath Antarctic ice shelf following breakaway of A-84 iceberg challenges existing scientific assumptions & highlights importance of deep-sea exploration in understanding climate change & biodiversity.

Key Highlights

A massive 510 sq. km iceberg A-84 broke away from George VI Ice Shelf on January 13, 2025.

The exposed seafloor previously covered by 150-meter-thick ice for centuries became accessible for exploration.

Scientists used remotely operated vehicle (ROV) SuBastian to explore newly exposed seafloor.

The mission was part of Challenger 150 UNESCO-endorsed global initiative for deep-sea research.

The submersible explored depths of up to 1,300 meters over eight days capturing high-resolution images & collecting biological samples.

Scientists observed diverse deep-sea ecosystems contrary to expectations.

Notable species discovered:

Giant sea spiders

Deep-sea octopi

Large corals & sponges

Icefish

A giant phantom jellyfish which can grow up to a meter wide

A vase-shaped sponge potentially hundreds of years old

Several potentially new species were also documented.

Deep-sea ecosystems typically depend on photosynthetic nutrient sources from surface waters.

However these organisms have survived under thick ice for centuries indicating alternative nutrient sources.

Possible factors sustaining these ecosystems:

Ocean currents transporting nutrients

Glacial meltwater providing essential minerals

Undiscovered deep-sea microbial food chains

Scientific Significance:

The findings challenge previous assumptions about life beneath Antarctic ice shelves.

Offers new insights into climate change impacts on marine biodiversity.

Provides evidence of long-term ecosystem resilience despite extreme conditions.

Historical Context:

Prior to this first evidence of bottom dwelling life under Antarctic ice shelves was reported in 2021 by British Antarctic Survey (BAS) researchers.

This new discovery significantly expands knowledge about hidden ecosystems beneath ice-covered oceans.

Ice Shelves

Category	Description	Examples & Locations	Significance
Definition	Large floating platforms of ice attached to land masses.	Found along coasts of Antarctica, Greenland & Canada.	Act as barriers, slowing glacier movement into oceans.
Formation	Formed when glaciers or ice sheets flow into ocean & extend outward.	Primarily in polar regions where temperatures allow ice accumulation.	Help regulate global sea levels.
Types	Based on stability & size: 1. Stable Ice Shelves (thick, long-lasting) 2. Thinning Ice Shelves (affected by climate change) 3. Collapsing Ice Shelves (disintegrating due to warming)	1. Ross Ice Shelf (Largest, Antarctica) 2. Larsen Ice Shelf (Antarctica, multiple collapses since 1995) 3. George VI Ice Shelf (Source of A-84 iceberg, Antarctica)	Provide habitat for unique ecosystems beneath ice.
Major Ice Shelves	1. Antarctica: Ross, Filchner-Ronne, Amery, Larsen, George VI 2. Greenland: Petermann, Nioghalvfjerdsbræ 3. Canada: Ward Hunt Ice Shelf (Arctic)	Mostly found in polar regions where land-based glaciers meet sea.	Their melting contributes to rising sea levels.
Threats & Climate Change Impact	Rising temperatures cause ice shelves to thin, break, or collapse, accelerating glacier flow into oceans.	Larsen B (collapsed in 2002), Larsen C (broke in 2017), A-68 (drifted into ocean, 2017)	Ice shelf disintegration can increase sea level rise & alter ocean currents.

Major Deep-Sea Research Missions

Mission Name	Year	Conducted By	Objective & Focus	Key Discoveries & Achievements
Challenger Expedition	1872-1876	British Royal Navy	First systematic deep-sea exploration	Identified 4,700+ new marine species, mapped ocean depths.
Glomar Challenger (Deep Sea Drilling Project)	1968-1983	US & International partners	Studied plate tectonics & ocean sediment layers	Confirmed seafloor spreading & provided proof of continental drift.
ALVIN (Submarine Program)	1964-present	Woods Hole Oceanographic Institution (USA)	Deep-sea hydrothermal vents & oceanic trenches exploration	Discovered hydrothermal vents, deep-sea organisms, explored Titanic wreck.
Hadal Exploration Program	2000s-present	Japan, USA	Exploring deepest parts of ocean	Explored Mariana Trench, found new species adapted to extreme pressure.
Challenger 150	2021-present	UNESCO-endorsed global project	Mapping & researching deep-sea biodiversity	New species discovered in Antarctic ice shelf region (2025), better understanding of deep-sea ecosystems.
Five Deeps Expedition	2018-2019	Victor Vescovo	First manned mission to reach deepest point in each ocean	Reached Mariana Trench (10,928 m), discovered plastic pollution in deep-sea.
Nereus & ROV SuBastian Missions	2010s-present	Schmidt Ocean Institute	Robotic deep-sea exploration	Discovered giant jellyfish, new corals & deep-sea sponges in Antarctica (2025).
International Ocean Discovery Program (IODP)	2013-present	International Collaboration	Studying Earth's past climate, plate tectonics	Drilling deep-sea sediment cores for climate & geological data.

For more information, please visit IAS GYAN

Sources:

INDIAN EXPRESS

PRACTICE QUESTION

Q. Consider following statements regarding Ice Shelves:

Ice shelves are floating extensions of glaciers that are found only in Antarctica.
The collapse of an ice shelf directly contributes to rising sea levels.
Larsen Ice Shelf, Ross Ice Shelf & George VI Ice Shelf are some of major ice shelves in world.

Which of statements given above is/are correct?

(a) 1 & 2 only
(b) 2 & 3 only
(c) 3 only
(d) 1, 2 & 3

Answer: (c)

Explanation:

Statement 1 is incorrect: Ice shelves are not exclusive to Antarctica. They are also found in Greenland as well as Canada. Some examples include Petermann Ice Shelf (Greenland) & Ward Hunt Ice Shelf (Canada).

Statement 2 is incorrect: collapse of an ice shelf itself does not directly raise sea levels as ice is already floating. However it removes barrier that holds back glaciers accelerating their flow into ocean which eventually raises sea levels.

Statement 3 is correct: Larsen Ice Shelf, Ross Ice Shelf & George VI Ice Shelf are important ice shelves located in Antarctica.