ASVAB (Armed Services Vocational Aptitude Battery)General Science (GS)Hard
A marine biologist is studying an ecosystem near a hydrothermal vent deep in the ocean. Unlike surface ecosystems, which rely on sunlight, the primary producers in this environment obtain energy through a process called:
- Achemosynthesis
- Bfermentation
- Crespiration
- Dphotosynthesis
Show answer & explanationAnswer & explanation
Correct answer: A. chemosynthesis
Hydrothermal vent ecosystems are aphotic (without light). Chemosynthesis is the biological conversion of one or more carbon molecules and nutrients into organic matter using the oxidation of inorganic chemical compounds (e.g., hydrogen sulfide) as an energy source, rather than sunlight.
Why the other options are wrong
- B. Fermentation is an anaerobic process to release energy from organic compounds, not a primary production method.
- C. Respiration is the process of breaking down organic matter to release energy, not producing it.
- D. Photosynthesis uses sunlight as an energy source, which is absent at deep-sea vents.
Chemosynthesis
The biological conversion of one-carbon molecules and nutrients into organic matter, using the oxidation of inorganic chemical compounds as an energy source.
- Does not require sunlight.
- Common in deep-sea hydrothermal vents and other aphotic environments.
- Often involves bacteria or archaea using hydrogen sulfide, methane, or iron compounds.
Memory trick: Photo needs light, Chemo needs chemicals.