◎ Encounters with white creatures that live in the deep sea

It's been two weeks since my last update. This is the third installment of my experience report, brought to you by Kentaro Amemiya, also known as Ameken. In my last report, I mentioned that the deep sea, where sunlight doesn't reach, is a lonely place with few living creatures. However, there are lively places even in the deep sea. What kind of places are they? This time, the Hyper Dolphin descended to a depth of approximately 1,500 meters.

Shortly after we began our descent, we could see what looked like rocky outcrops on the seabed on the monitor. Occasionally, these rocky outcrops appeared whitish, so I thought that part of the seabed must be made of white bedrock. But the next moment, I realized that those white things were actually creatures swarming on the rocky surface.

They were absolutely densely packed all over the rock face. And something was bubbling up from the cracks in the rock, rising higher and higher! When I saw that sight, I was so excited that I got goosebumps.

This area is called a hydrothermal vent zone. Simply put, it's like a hot spring bubbling up from the seabed. However, the water that erupts here is over 200°C. Furthermore, the water contains sulfides and other substances that are toxic to humans. How do living things survive in such a harsh environment?

These white creatures include shrimp, crabs, and polychaete worms. Among them, the one that particularly caught my eye was the Goemon squat lobster (pictured above).

Now, the Goemon shrimp has fluffy hairs around its belly (see photo below). It grows bacteria that thrive on sulfides and other nutrients between these hairs, and then feeds on them to survive. In this way, many creatures that live here utilize sulfides and other substances contained in hydrothermal vents to survive. In the deep sea where sunlight does not reach, organic matter, which is a gift from solar energy, is limited, so they obtain energy from hydrothermal vents and other sources.

After touching organisms collected from a hydrothermal vent area, I casually smelled my hands and thought, "Huh?" There was a different smell than usual. Normally, after touching creatures that have come up from the sea, your hands smell like the "seashore." But the smell coming from my hands that day was... the "smell of a hot spring," the smell of sulfur!! Looking back, it makes sense since the smell came from around hydrothermal vents containing sulfides, but at the time it seemed strange.

Now, next time will be the final installment of the experience report. I will introduce another objective of this investigation.

Photo above: Packed with Goemon shrimp!
Photo below: Goemon shrimp. It uses the hairs visible from its sides to increase bacteria.

​Report, Part 1
​Report, Part 2

[Tokyo Sea Life Park]

(July 18, 2008)