According to the passage, why did the discovery of hydrothermal vents surprise marine biologists?
Hydrothermal vents, discovered along mid-ocean ridges in the late 1970s, fundamentally altered biological understandings of life's energy sources. Prior to their discovery, scientists presumed that all oceanic ecosystems ultimately depended on solar radiation driving photosynthetic energy capture in surface waters. In stark contrast, hydrothermal vent communities thrive miles beneath the photic zone under crushing hydrostatic pressures and total darkness. Geothermally heated seawater, enriched with dissolved minerals and hydrogen sulfide (), spews from tectonic fissures at temperatures frequently surpassing . Rather than relying on sunlight, specialized autotrophic bacteria use chemosynthesis, oxidizing hydrogen sulfide to synthesize organic molecules from inorganic carbon dioxide (). These chemolithoautotrophic microbes form the trophic foundation of the entire benthic ecosystem, sustaining dense colonies of giant tube worms (Riftia pachyptila), vent crabs, and benthic bivalves through complex symbiotic and predatory relationships.
Answer and explanation
Correct answer: C. It proved that sunlight is not the sole primary energy foundation for complex ecosystems.
- Step 1: Scan the opening lines of the passage regarding historical scientific assumptions before the discovery of hydrothermal vents.
- Step 2: The text states that scientists previously assumed "all oceanic ecosystems ultimately depended on solar radiation driving photosynthetic energy capture." The discovery overturned this paradigm by proving that ecosystems can thrive through chemosynthesis without relying on sunlight.
Answer
It proved that sunlight is not the sole primary energy foundation for complex ecosystems.
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More Academic Reading: Natural Sciences questions
- The word stark in the passage is closest in meaning to:
- Which of the following compounds serves as the primary electron donor for chemosynthetic vent bacteria?
- It can be inferred from the passage that giant tube worms (Riftia pachyptila):
- The word spews in the passage is closest in meaning to:
- All of the following are mentioned in the passage as physical attributes of hydrothermal vent habitats EXCEPT:
- What was the primary cause of sea level decline during the Last Glacial Maximum described in the text?