Question

Difficulty: HardIdentifying Explicit Details

The passage below is adapted from an essay on deep-sea exploration.

In the early months of 1977, a research expedition set out for the Galapagos Rift, an underwater volcanic ridge located in the eastern Pacific Ocean. Organized by Oregon State University, the Woods Hole Oceanographic Institution, and other research bodies, the expedition aimed to locate active hydrothermal activity. Geologists had hypothesized that seawater must circulate deep into the oceanic crust near mid-ocean ridges, where it would be heated by magma chambers below before venting back into the cold ocean depths. However, because no such vent had ever been directly observed, the expedition's primary goal was geological rather than biological. Indeed, none of the chief scientists on the expedition were biologists; they expected to find nothing more than warm water and bare rock.

Before deploying the three-person crewed submersible Alvin, scientists scanned the ocean floor using a heavily instrumented, unmanned sled named ANGUS (Acoustically Navigated Geological Undersea System). Towed by the surface research vessel Knorr, ANGUS was equipped with cameras and temperature sensors designed to detect the subtle thermal plumes expected from deep-sea hot springs. On February 15, 1977, ANGUS recorded a temperature anomaly of only 0.1 degrees Celsius above the ambient deep-sea temperature. Although tiny, this anomaly was accompanied by high-resolution photographs showing clusters of large, white clam shells littered across the basaltic rock, suggesting that something unusual was happening on the seafloor.

Two days later, on February 17, 1977, Alvin made its historic 713th dive. Inside the titanium pressure sphere were pilot Jack Donnelly and geologists John Corliss and John Edmond. Descending to a depth of 2,500 meters, they guided the submersible toward the coordinates flagged by ANGUS. When they reached the seafloor, they were astonished to find a vibrant oasis teeming with life, completely contrasting with the barren, desert-like expanse of the surrounding abyssal plains. Clustered around openings in the volcanic rock were dense populations of giant tube worms, crabs, and large white clams, some up to thirty centimeters in length.

Using Alvin’s mechanical arm, the scientists inserted a temperature probe directly into one of the fluid vents, which they named Clambake I. The probe registered a temperature of 17 degrees Celsius (approximately 63 degrees Fahrenheit). While this temperature seems modest, it was remarkably warm compared to the ambient bottom water, which hovered at a near-freezing 2 degrees Celsius.

Crucially, the venting water did not contain oxygen. Instead, it was highly enriched with toxic minerals, most notably hydrogen sulfide, a chemical compound that smells of rotten eggs. This chemical signature provided the key to solving the biological mystery of how such a dense community could survive in the absolute darkness of the deep ocean, where sunlight could not penetrate to fuel photosynthesis. Rather than relying on solar energy, these ecosystems were powered by chemosynthesis. Unseen, specialized bacteria oxidized the hydrogen sulfide to produce organic matter, establishing a food web independent of the Sun. Some of these bacteria lived symbiotically inside the tissues of the giant tube worms, which lacked both mouths and digestive tracts, relying entirely on their internal bacterial partners for nutrition.

The discovery at the Galapagos Rift fundamentally altered our understanding of life on Earth. It proved that complex ecological communities could thrive completely isolated from solar radiation, utilizing chemical energy from the planet's interior. This realization expanded the definition of habitable zones, not just on Earth, but potentially on icy moons and distant planets within our solar system and beyond.

Based on the passage, is the statement that the high-resolution photographs captured by the unmanned sled ANGUS on February 15, 1977, provided the first visual evidence of giant tube worms clustered on the seafloor true or false?

Answer: Answer

Answer

False
The correct answer is false because the passage explicitly states that the photographs taken by the unmanned sled ANGUS on February 15 showed only clusters of large, white clam shells. The giant tube worms were not observed until two days later when the crewed submersible Alvin reached the seafloor.

Step-by-Step Solution

1
Locate the mention of the unmanned sled ANGUS and the date February 15, 1977, in the passage.
The second paragraph explains that on February 15, 1977, the unmanned sled ANGUS recorded a temperature anomaly and took high-resolution photographs.
This establishes the source of the photos and the date to verify what they showed.
2
Identify what the photographs explicitly revealed according to the text.
The text states the photographs showed 'clusters of large, white clam shells littered across the basaltic rock.'
This determines the exact visual evidence captured by the unmanned sled.
3
Identify when the giant tube worms were first observed.
The third paragraph states that on February 17, 1977, the crew of the submersible Alvin descended to the seafloor and found 'giant tube worms, crabs, and large white clams.'
This confirms that the giant tube worms were first seen during Alvin's dive, two days after the initial photographs were taken.
4
Compare the statement's claim to the chronological facts in the passage.
The statement claims the photos from February 15 showed giant tube worms, whereas the text says they only showed clam shells. Therefore, the statement is false.
This resolves the truth value of the statement based strictly on explicit details.

Key Concept

Identifying explicit details and distinguishing between chronologically distinct events or findings in a text.
Estimated Time:2m 0s
Rate this question