GED Science TestEarth and Space ScienceHard
A team of researchers is studying a deep-sea hydrothermal vent ecosystem. They observe a thriving community of organisms, including tube worms and chemosynthetic bacteria, in complete absence of sunlight. What is the primary energy source for this ecosystem?
- ALunar tidal energy
- BDecomposition of organic matter from the surface
- CGeothermal energy from chemical reactions
- DPhotosynthesis
Show answer & explanationAnswer & explanation
Correct answer: C. Geothermal energy from chemical reactions
Deep-sea hydrothermal vent ecosystems are unique because they exist in perpetual darkness. Instead of photosynthesis, the primary producers (chemosynthetic bacteria) derive energy from chemical reactions involving compounds released from the vents, such as hydrogen sulfide, which is a form of geothermal energy.
Why the other options are wrong
- A. Lunar tidal energy primarily affects ocean currents and tides, not the primary energy source for deep-sea ecosystems.
- B. While some organic matter sinks from the surface, it is not the primary energy source for the entire thriving chemosynthetic community at vents.
- D. Photosynthesis requires sunlight, which is absent in the deep sea.
Chemosynthesis
Chemosynthesis is the process by which certain organisms, primarily bacteria, produce organic compounds using chemical energy rather than light energy.
- Common in deep-sea hydrothermal vents.
- Uses inorganic chemical reactions (e.g., hydrogen sulfide oxidation).
- Forms the base of the food web in these unique ecosystems.
Memory trick: Vents are hot, chemicals flow, life below needs no sun's glow.