Answer: Levels of oxygen in the lake will drop and will reduce the lake's ability to support life.
Explanation: Phytoplankton are the producers in aquatic ecosystems, so they belong to the first throphic level and do photosynthesis releasing oxygen into the lake.
If toxic chemicals are not cleaned, a lot of phytoplakton organisms will die, reducing the autotroph population (the one that make photosynthesis) and oxygen wont be produced, so the lake cannot support other organisms like zooplankton or fishes that need oxygen to live.
Answer:
Levels of oxygen in the lake will drop and will reduce the lake's ability to support life.
Explanation:
Hope this helps :)