How Giant Tube Worms Survive at Hydrothermal Vents | I Contain Multitudes

Summary

In 1977, a deep-sea expedition near the Galapagos Islands uncovered hydrothermal vents, radically changing our understanding of life in extreme environments. The crew aboard the Alvin sub discovered giant tubeworms thriving in total darkness without a mouth, gut, or digestive system. Harvard grad student Colleen Cavanaugh proposed that symbiotic bacteria inside these worms used hydrogen sulfide from the vents to perform chemosynthesis, producing food for both the bacteria and worms. This groundbreaking discovery revealed a new ecosystem powered by chemicals, not sunlight, and suggested this could have been how early life on Earth survived.

Takeaways

• 🚀 In 1977, a submersible called Alvin discovered a thriving deep-sea ecosystem near hydrothermal vents, defying expectations.
• 🌋 The Alvin crew found deep-sea hydrothermal vents at 7,500 feet, where volcanic activity superheated water.
• 🐛 The crew discovered giant tubeworms, Riftia pachyptila, living in abundance around the vents.
• 🤯 These worms have no mouth, gut, or anus, puzzling scientists on how they survive.
• 🧫 Colleen Cavanaugh proposed that the worms rely on symbiotic sulfur-oxidizing bacteria for survival, which was later proven true.
• ⚗️ The bacteria use hydrogen sulfide from the vents to perform chemosynthesis, providing food for the worms.
• 🌑 Chemosynthesis, unlike photosynthesis, uses chemical energy from sulfides rather than sunlight.
• 🧪 The bacteria live in the worms’ trophosome, an organ that processes sulfur and feeds the host worm.
• 🩸 The worms have a blood supply in their plume that helps transport hydrogen sulfide and oxygen to the bacteria.
• 🌍 This discovery of chemosynthesis revealed a new way life can thrive in extreme, sunless environments, potentially shedding light on early life on Earth.

Q & A

What was the significance of the 1977 Alvin dive?

The 1977 Alvin dive was significant because it led to the discovery of deep-sea hydrothermal vents and an unexpected ecosystem thriving without sunlight. This changed our understanding of how life can survive in extreme environments.

What surprised the Alvin crew about the life forms they discovered near the hydrothermal vents?

The Alvin crew was surprised to find an abundance of life, including giant tubeworms, living in extreme conditions with no sunlight and under immense pressure. This was unexpected in such a harsh environment.

What is unique about the tubeworms, Riftia pachyptila, found near hydrothermal vents?

Riftia pachyptila are unique because they have no mouth, gut, or anus, yet they thrive in extreme environments. Their bodies are encased in white tubes, and their crimson plume helps them survive by facilitating chemosynthesis.

How do the tubeworms survive without a digestive system?

Tubeworms survive through a process called chemosynthesis, facilitated by symbiotic bacteria living in their trophosome. These bacteria use hydrogen sulfide from the vents as an energy source to produce food for the worms.

What is chemosynthesis, and how does it differ from photosynthesis?

Chemosynthesis is the process by which certain organisms use chemicals, such as hydrogen sulfide, as an energy source to produce food, unlike photosynthesis, which relies on sunlight. Chemosynthesis is common in deep-sea environments where sunlight is absent.

What role do the bacteria play in the tubeworm's survival?

The bacteria inside the tubeworm’s trophosome process hydrogen sulfide and oxygen to produce organic compounds via chemosynthesis, providing nutrients for both themselves and the worm. This symbiotic relationship allows the worm to thrive without a digestive system.

How do the bacteria enter the tubeworm if it has no mouth?

The bacteria enter the tubeworm through its skin and body wall, embedding themselves in the trophosome, where they help the worm process hydrogen sulfide and oxygen for chemosynthesis.

How do tubeworms obtain the hydrogen sulfide and oxygen needed for chemosynthesis?

Tubeworms use their crimson plume, which functions like a lung, to absorb hydrogen sulfide and oxygen from the water. The blood in the plume carries these substances to the bacteria in the trophosome, where chemosynthesis occurs.

Why was the discovery of chemosynthesis important for understanding deep-sea ecosystems?

The discovery of chemosynthesis revealed that life can thrive in environments without sunlight, entirely dependent on chemicals from hydrothermal vents. This challenged previous assumptions and opened up new avenues for understanding extreme ecosystems.

How might chemosynthesis have played a role in early life on Earth?

Chemosynthesis may have been crucial for the survival of the earliest life forms on Earth, especially in environments where sunlight was not available. This discovery suggests that life could have originated in extreme, chemically rich environments like hydrothermal vents.