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Marine Biologist: The accelerated structural degradation of the deep-water coral Lophelia pertusa in the Boreal Basin over the last twenty years is widely attributed to oceanic acidification. Proponents of this theory argue that higher acidity depletes the dissolved calcium carbonate that the corals extract from the water to build their skeletons. However, recent hydrographic surveys demonstrate that the overall concentration of dissolved calcium carbonate in the Boreal Basin has actually risen by nearly twelve percent over this exact timeframe. Clearly, the degradation of the coral's structure is not a consequence of oceanic acidification, but must stem from a different environmental stressor, such as the recently documented increase in deep-sea trawling.

Statement: If true, the fact that the recent twelve percent increase in dissolved calcium carbonate in the Boreal Basin consists entirely of aragonite—the specific crystalline form of calcium carbonate that constitutes the existing skeletons of Lophelia pertusa and which dissolves rapidly when exposed to higher acidity—weakens the marine biologist's argument.

Answer: Answer

Answer

The statement is True. The newly introduced fact actively undermines the marine biologist's conclusion by demonstrating that the increased calcium carbonate is actually a symptom of the acidification destroying the coral.
The assertion is true because the newly introduced fact provides a devastating alternate interpretation of the biologist's evidence. The biologist assumes that the twelve percent increase in dissolved calcium carbonate means the environment is hospitable and that acidification isn't starving the coral. However, the new fact reveals that this increase is actually the dissolved remains of the corals' own skeletons. This causal inversion completely destroys the biologist's conclusion by demonstrating that acidification is indeed the direct cause of the degradation, making the statement a powerful weakener.

Step-by-Step Solution

1
Analyze the argument's core structure to identify the premise and conclusion.
Premise: Dissolved calcium carbonate has risen by twelve percent. Conclusion: Acidification is not causing the coral degradation; a different stressor is responsible.
Isolating the argument's logical core is necessary to identify its structural vulnerabilities.
2
Identify the underlying assumption bridging the premise and the conclusion.
The biologist assumes that an increase in dissolved calcium carbonate means the environment has an abundance of resources for the coral, implying that the corals are safe from the resource depletion normally caused by acidification.
Weakening an argument at the highest level of difficulty almost always requires attacking an unstated, flawed assumption.
3
Apply the new statement's evidence to the biologist's assumption.
The statement reveals that the twelve percent increase is composed of aragonite, which is actively dissolving off the corals' own skeletons as a direct result of higher acidity.
This establishes a causal inversion. The premise (higher carbonate) is not proof of the coral's safety; it is the chemical footprint of the coral being actively destroyed by the exact cause the author prematurely dismissed.

Key Concept

Evaluating alternate causes and recognizing causal inversions where evidence intended to disprove a phenomenon actually serves as a direct symptom of it.
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