Anoxia, or a lack of oxygen in bodies of water, leads to __________.

• A. higher oxygen concentrations
• B. increased rates of photosynthesis
• C. enhanced growth of oxygen-dependent fish
• D. the death of aerobic aquatic organisms

Answer: (D)

Verified step by step guidance

1. Understand the term 'anoxia': Anoxia refers to a condition where there is an absence or extremely low levels of oxygen in a particular environment, such as a body of water. This is critical for understanding the impact on aquatic life.
2. Recall the role of oxygen in aquatic ecosystems: Oxygen is essential for the survival of aerobic organisms, which rely on it for cellular respiration to produce energy.
3. Analyze the effects of anoxia: When oxygen levels drop significantly, aerobic organisms, such as fish and other oxygen-dependent aquatic species, cannot perform cellular respiration effectively, leading to their death.
4. Eliminate incorrect options: Higher oxygen concentrations and increased rates of photosynthesis are contradictory to the condition of anoxia, as it specifically refers to low oxygen levels. Enhanced growth of oxygen-dependent fish is also incorrect because these organisms cannot survive without sufficient oxygen.
5. Conclude the correct answer: The death of aerobic aquatic organisms is the direct consequence of anoxia, as they are unable to sustain their metabolic processes in the absence of oxygen.