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Creatures of the Deep
Deep under the ocean's surface, jets of hot water gush from rifts in the seafloor. These deep sea vents, called hydrothermal vents, spring up on the ocean floor almost every day. Some shoot out hot clear fluid. Others spout water that is black with minerals. The water in some hydrothermal vents is hotter than 370 degrees Centigrade—hotter than molten lead. Yet a number of bizarre animals thrive on the heat and minerals at these vents. Unlike most life on Earth, which depends on energy from the Sun, this food chain depends on the energy from chemicals. Specially adapted bacteria thrive on chemicals that would be toxic to most other animals on Earth. In turn, these bacteria provide energy for the entire community of vent animals. Some animals, like the giant tubeworms and giant white clams, get their nutrition from the bacteria living inside their bodies.
Definition: the vast landscape of the ocean bottom
Characteristics: expansive plains, mountains, trenches, ridges, and hydrothermal vents
Where: in all the oceans of the Earth
Inhabitants: over 200,000 mud-dwelling animals, most of which are tiny one-celled organisms
Significance: one of the most diverse ecosystems on Earth
With the discovery that deep sea animals live without sunlight, scientists believe it is possible that:
the first life on Earth may have originated at the deep seafloor
there could be life elsewhere in the Universe
both A and B
Correct!
The first life on Earth may have originated on the deep seafloor, protected from the cosmic rays that bombarded Earth billions of years ago. It is also possible that life is found elsewhere in the Universe, such as in the warm, wet places beneath the surface of Mars.
Most seafloor dwellers survive on "sea snow." Sea snow refers to falling particles of:
food dropped by humans on the ocean's surface
dead plants and animals, and animal waste
the ice that forms in cold waters
Correct!
Sea snow consists of particles of dead plants, animals, and animal waste that fall from above. Crabs, snails, and sea stars (starfish) scavenge sea snow off the surface of the seafloor.
The deepest trenches of the ocean floor are about as deep as the Grand Canyon.
Fiction
The deepest trenches of the ocean floor are more than six times as deep as the Grand Canyon. Some drop as much as 11 kilometers (7 miles) below sea level.
The sparse ecosystem of the deep seafloor has little diversity compared to a tropical rain forest.
Fiction
With more than 200,000 species living in its distinct habitats, the seafloor is now compared to such diverse ecosystems as the rain forest.