Aquatic plants that float on water in a pond can reproduce rapidly, covering the surface of the pond. These aquatic plants can impact the oxygen levels in the pond when when they die. Sometimes the oxygen levels are so severely impacted that there is no longer enough oxygen in the water for fish to survive.
Why is there not enough oxygen for the fish to survive when a large population of the aquatic plants die?
a. The bacteria use oxygen in the water as they decompose the plants.
b. The dead plants are covering the surface of the pond and blocking the sunlight.
c. The dead plants create a blanket on the top of the pond causing the water to warm up.
d. The plants produce carbon dioxide instead of oxygen when they die.
I think it is A
https://freshwater-aquaculture.extension.org/if-algae-produce-oxygen-in-a-pond-how-can-having-too-much-algae-cause-an-oxygen-depletion/
You are correct. The reason there is not enough oxygen for the fish to survive when a large population of aquatic plants die is because of the activity of bacteria. When the plants die and sink to the bottom of the pond, the bacteria start decomposing them. During this process, the bacteria use up dissolved oxygen in the water. As the decomposition continues, the oxygen levels in the water decrease, making it difficult for fish and other organisms to obtain the necessary oxygen for survival.
To determine the correct answer, it's important to understand the process of decomposition and the role of bacteria in it. When organic matter, such as dead plants, breaks down, bacteria break down the complex molecules into simpler ones. This breakdown process requires oxygen as the bacteria consume the organic matter and release carbon dioxide and energy.
So, in this scenario, option A is the correct answer because bacteria use oxygen in the water as they decompose the dead aquatic plants.