Question

a team of marine biologists observe that an inland sea is covered with a green slime. they also observe that besides fishing, the local population practices large - scale farming in the area. in what possible way can farming be responsible for the state of the lake?
○ a. nutrients from fertilizers on the farm wash off into the lake and cause the green slimy algal bloom.
○ b. pesticides from the farm wash off into the lake, causing algae to die and producing a green slime.
○ c. plants growing in the farm increase the chlorophyll levels in the ground, which runs off into the lake, causing the green slime.
○ d. the plants in the farm deplete the lake of nutrients and kill off microscopic organisms, causing the green slime.
○ e. the green slime in the lake is a toxin produced by pesticides that run off into the lake.

Explanation:

• Option A: Fertilizers contain nutrients like nitrogen and phosphorus. When these nutrients wash off into water bodies (through runoff), they act as a food source for algae. Excessive nutrients lead to an overgrowth of algae, creating an algal bloom which can appear as a green slime.
• Option B: Pesticides are more likely to harm fish and other aquatic organisms rather than directly causing a green - slime - like algal bloom. Algae need nutrients to grow, and pesticides would not provide the necessary nutrients for an algal bloom.
• Option C: Chlorophyll is a pigment in plants. While plants have chlorophyll, the chlorophyll from plants on the farm does not directly translate to chlorophyll running off into the lake in a way that would cause a green - slime - like algal bloom. Algal blooms are caused by algal growth due to nutrient availability.
• Option D: If plants depleted the lake of nutrients, it would be less likely to support an algal bloom (since algae need nutrients to grow). Algal blooms occur when there is an excess of nutrients.
• Option E: Pesticides are not known to produce a green - slime - like substance that is characteristic of an algal bloom. Algal blooms are biological overgrowths of algae, not chemical toxins from pesticides in the form of a green slime.

Answer:

A. Nutrients from fertilizers on the farm wash off into the lake and cause the green slimy algal bloom.