but the ocean’s salt lowers the
freezing point of the water. Many
deep-sea areas have never been lit
by the sun. Still, life thrives in them.
Instead of using the sun for energy,
deep-sea animals eat bacteria or
each other.
Some marine ecosystems have been
affected by climate change. But
deep-sea ecosystems have been
thriving for billions of years. One of
the main reasons is that people do
not live in the deep sea. Scientists
have recorded global warming in
many parts of the world in recent
years. But the water temperatures of
the deep sea have remained steady
since 2005.
17,000
Number of animal
species known to live in
the deep sea.
• Water more than one
mile (1.6 km) deep covers
more than two-thirds of
the planet.
• Sunlight has never
reached many areas of
the deep sea.
• Many animals that live in
the deep sea survive by
eating bacteria.
• Deep-sea ecosystems
have thrived for billions
of years.
Atlantic wolffish
have a natural
antifreeze in their blood
to keep it flowing in
the cold waters of the
deep sea.
21
