Deep sea creatures live under extreme conditions

The water is cold, dark, and adds pressure from all sides. To survive in the deep sea, animals must be anti-social and easily satisfied.

In the summer of 2015, two scientists from Hawaii discovered an unknown sea sponge the size of a family car. The sponge was 3.5 m long, 2 m tall, and probably more than 1,000 years old. According to most oceanographers, we only know about one third of the species that exist in the deep sea, and other large, unknown species such as whales, giant squid, and fish may be hiding in the 95 % of the oceans that humans have not yet seen. The deep sea is not an easy place to explore nor live in. The extreme pressure makes up a specific challenge – both to deep sea species and to exploration vessels.

ETERNAL DARKNESS: Light disappears quickly with depth, and already after 200 m, the light is so dim, that plants cannot perform photosynthesis. At 200-1,000 m, it is twilight, and below 1,000 m, it is pitch-dark.

CONSTANT COLD: Temperatures in the deep sea are 0-3 °C. The cold means that physiological processes are slow. Deep sea animals grow, digest food, and move more slowly than the animals in the upper water layers. On the other hand, they live for 100+ years.

SOLITUDE: In the deep sea, both food and mates are sparse. Consequently, many deep sea animals probably only eat and mate once in their lifetimes.