ECOLOGY
ORGANISMS AND THE ENVIRONMENT
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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lack of oxygen in the water as they die
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lack of oxygen as they grow
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more food for fish
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None of the above
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Detailed explanation-1: -When these dense algal blooms eventually die, microbial decomposition severely depletes dissolved oxygen, creating a hypoxic or anoxic ‘dead zone’ lacking sufficient oxygen to support most organisms.
Detailed explanation-2: -Low dissolved oxygen (DO) primarily results from excessive algae growth caused by phosphorus. Nitrogen is another nutrient that can contribute to algae growth. As the algae die and decompose, the process consumes dissolved oxygen.
Detailed explanation-3: -Nutrient pollution, excess phosphorus and nitrogen from either fertilizers or untreated wastewater, causes the uncontrolled growth of the algae that lead to the algal blooms.
Detailed explanation-4: -The overgrowth of algae consumes oxygen and blocks sunlight from underwater plants. When the algae eventually dies, the oxygen in the water is consumed. The lack of oxygen makes it impossible for aquatic life to survive.
Detailed explanation-5: -Algal blooms can be dramatic and are a result of excess nutrients from fertilizer, wastewater and stormwater runoff, coinciding with lots of sunlight, warm temperatures and shallow, slow-flowing water.