The researchers studied how different underwater plants can help clean up a polluted lake by removing phosphorus. They found that Ceratophyllum demersum was the most effective at absorbing phosphorus, with a high growth rate and removal rate. This plant can help keep phosphorus levels low in the water by taking it up and preventing it from being released back into the lake. Overall, Ceratophyllum demersum is a good choice for cleaning up polluted lakes and can grow well even in contaminated water.