lautnusantara.com Oxygen is essential for most life forms on Earth, including marine animals. However, the ways in which different species obtain and utilize oxygen vary significantly. While some marine creatures have adapted to low-oxygen environments, only a few can survive completely without oxygen for extended periods. This article explores how marine animals cope with oxygen availability and whether some can live without it entirely.

How Marine Animals Breathe

Most marine animals rely on oxygen dissolved in water to survive. They extract this oxygen through specialized respiratory structures:

1. Gills – Fish, mollusks, and crustaceans use gills to filter oxygen from water.
2. Lungs – Marine mammals like whales and dolphins surface to breathe air through lungs.
3. Skin Respiration – Some amphibians and sea snakes absorb oxygen directly through their skin.
4. Modified Breathing Structures – Some species, like sea cucumbers, use their cloaca (anal breathing) to extract oxygen.

Marine Animals That Can Survive with Low Oxygen

Certain marine creatures have evolved unique adaptations to survive in hypoxic (low-oxygen) environments:

• Deep-Sea Creatures – Animals like giant tube worms and some deep-sea fish live in oxygen-scarce environments, relying on symbiotic bacteria or slow metabolisms.
• Jellyfish – Many jellyfish species thrive in low-oxygen waters because they have simple body structures and require little oxygen.
• Some Crustaceans – Crabs and lobsters can tolerate low-oxygen conditions for extended periods.

Can Any Marine Animal Live Without Oxygen?

Until recently, it was believed that no animal could survive without oxygen indefinitely. However, researchers discovered Henneguya salminicola, a microscopic parasite that lives in salmon and does not rely on oxygen. Unlike other animals, it lacks mitochondria, the structures that process oxygen in cells, making it the first known multicellular organism to thrive anaerobically.

While most marine animals depend on oxygen, some have developed remarkable adaptations to survive in low-oxygen conditions. However, true oxygen-free survival is extremely rare, with Henneguya salminicola being the only known example. As ocean conditions change due to climate change and pollution, understanding how marine animals adapt to oxygen availability becomes increasingly important.