Question

watershed.
harmful algal blooms are characterized by a rapid increase in the population of a type of algae that produces toxins. toxins are chemicals that are poisonous to living things. the rapid reproduction of this type of algae is caused by the presence of sunlight, warm water, and an increase in the level of nutrients in the water. the nutrients come from farms that use chemicals to make their plants healthy. they are carried to lakes and rivers by runoff.
suppose this scenario was modeled in the lab. how would the populations of the biotic factors be affected? check all that apply.

• mosquito larvae will increase.
• heron population will increase.
• algae population will increase.
• trout population will decrease.
• minnow population will decrease.

Explanation:

1. Algae: The scenario states nutrient runoff, warm water, and sunlight trigger rapid algal growth, so their population increases.
2. Minnows/Trout: The algae produce toxins poisonous to living things, so these fish populations will decrease as they are affected by the toxins or lose food sources.
3. Mosquito larvae: No link to increased larvae is given; toxins or ecosystem disruption would likely not boost their numbers.
4. Herons: With trout/minnow populations decreasing, herons (which prey on these fish) would lose food, so their population would not increase.

Answer:

• Algae population will increase.
• Trout population will decrease.
• Minnow population will decrease.