In News:

Scientists who recently discovered that metal lumps on the dark seabed make oxygen, have announced plans to study the deepest parts of Earth's oceans in order to understand the strange phenomenon.

What is Dark Oxygen?

Dark Oxygen refers to oxygen produced deep under the ocean without sunlight or photosynthesis.
Discovered in July 2024, this challenges the long-standing belief that photosynthesis is the sole natural source of oxygen.

Where was it discovered?

• Location: Clarion-Clipperton Zone (CCZ), 13,100 feet deep in the North Pacific Ocean, between Hawaii and Mexico.
• Zone Significance: Rich in polymetallic nodules containing manganese, iron, cobalt, nickel, copper, and lithium — crucial for green technologies.

Mechanism of Oxygen Production

• Polymetallic nodules on the seafloor generate oxygen via electrochemical reactions.
• These nodules split seawater (H?O) molecules into hydrogen and oxygen, without any light.
• This process is non-biological and independent of photosynthesis.

Why is this Discovery Important?

• Scientific Paradigm Shift: Challenges the idea that photosynthesis is the only natural pathway for oxygen generation.
• Origins of Life: Suggests that oxygen production may have existed before photosynthetic organisms, reshaping theories of early Earth’s evolution.
• Astrobiological Implications: Indicates the possibility of oxygen-rich environments on other planets, even without sunlight — enhancing the search for extraterrestrial life.
• Environmental Tech Potential: Could lead to innovations in renewable energy and carbon-neutral technologies, using metal-based catalysis.

About the Clarion-Clipperton Zone (CCZ)

• Geographic span: Between Hawaii and Mexico in the North Pacific Ocean.
• Resources: Contains vast reserves of critical minerals like manganese, nickel, cobalt — essential for electric vehicles and solar technology.
• A focus area for deep-sea mining and sustainability studies.

Why is it in the News?

Developing a domestic manufacturing infrastructure for electrolyzers is expected to reduce the cost of green hydrogen and strengthen India's competitive advantage.

What are Electrolysers?

• Electrolysers are devices that produce hydrogen through a chemical process called electrolysis, which splits water molecules into hydrogen and oxygen molecules using electricity.

How do They work?

• These devices consist of a stack of conductive electrodes separated by a membrane, to which a high voltage and current are applied.
• This induces an electric current in the water, causing it to decompose into its constituents: hydrogen and oxygen.
• The generated oxygen is either released into the atmosphere or stored for future use as a medical or industrial gas.
• The hydrogen produced can be stored as a compressed gas liquefied for industrial use or utilised in hydrogen fuel cells, which power various transportation vehicles like trains, ships, and aircraft.

Types of Electrolysers:

• Alkaline Electrolysers: This technology, predominantly used by the fertiliser and chlorine industries, employs thick membranes and nickel-based electrodes.
  • It currently represents a significant portion of global electrolyser capacity.
• Proton Exchange Membrane (PEM) Electrolysers: Operating at high pressure, PEM electrolysers utilise thin perfluorosulfonic acid (PFSA) membranes.
  • Though they require gold and titanium-plated electrodes and catalysts like platinum, iridium, and ruthenium, they produce high-purity hydrogen and are easy to cool, making them a popular choice.
• Solid Oxide Electrolysis Cell (SOEC) Electrolysers: These devices utilise heat to produce hydrogen from steam and are ideal for locations with available heat sources such as nuclear or industrial facilities.
  • Operating at high temperatures ranging from 500 to 850 degrees Celsius.
• Anion Exchange Membrane (AEM) Electrolysers: Operating at significantly lower temperatures of 50 to 60 degrees Celsius, AEM electrolysers combine the less harsh conditions of alkaline electrolysers with the simplicity and high efficiency of PEM electrolysers.

Electrolyzers and Green Hydrogen Production:

• Green hydrogen is renewable hydrogen produced using water electrolysis technology and electricity generated from renewable energy sources, such as solar or wind.
• It is gaining unprecedented momentum globally, and it is believed that it is a key component in accelerating the shift to clean energy.
• The commercialization of electrolyzers can make green hydrogen more readily available and enable energy systems across the globe to undergo fundamental transformations to lower emissions and reduce their negative impact on the environment.

Why in the News?

Scientists from Mahidol University in Thailand have been exploring the potential of watermeal, the smallest flowering plant on Earth, as a source of nutrition and oxygen for astronauts.

What is Watermeal?

• The Watermeal scientifically known as Wolffia, is often mistaken for algae, but they're actually the smallest flowering plants in the world!
• Its simplicity and rapid growth rate make it an ideal candidate for studying the effects of altered gravity on plant development.
• this tiny plant is aquatic, predominantly floating on the surface of water bodies.
• Because watermeal doesn’t have any roots, stems or leaves, it is basically just a sphere floating on a body of water.
• It's a prolific producer of oxygen through photosynthesis and belongs to the duckweed family (Lemnaceae).
• Each individual watermeal plant is extremely small, roughly the size of a pinhead.
• It has a simple, globular, and rootless structure, often appearing like minute green grains on the water.
• Watermeal thrives in quiet, nutrient-rich freshwater environments like ponds, lakes, and marshes.
• The plant is found globally, with a significant presence in Asia and Thailand.
• Watermeal is known to be a rich source of protein, making it a nutritious foodstuff.
• In Thailand, it has been part of the local diet for generations, appearing in dishes ranging from soups to salads.