Tennessee Wastewater Operator Practice Exam

What unique ability allows cyanobacteria to thrive when green algae cannot?

1. Use nitrogen gas from the atmosphere

2. Store energy as glucose

3. Absorb pollutants

4. Produce enzymes to break down waste

The correct answer is: Use nitrogen gas from the atmosphere

Cyanobacteria possess the unique ability to utilize nitrogen gas from the atmosphere, which allows them to thrive in environments where green algae may struggle. This ability is particularly crucial in nutrient-poor conditions. While green algae primarily rely on readily available forms of nitrogen, such as ammonium or nitrate from the water, cyanobacteria can fix atmospheric nitrogen using specialized cells called heterocysts. This process of nitrogen fixation enables them to convert gaseous nitrogen into ammonia, which can then be used in the synthesis of vital organic compounds and proteins. This capability not only allows cyanobacteria to thrive in diverse ecological niches but also contributes to nutrient cycling in aquatic ecosystems. The nitrogen fixed by cyanobacteria can enhance the growth of other organisms once it is released back into the environment, facilitating a community where various species can coexist. This aspect underscores their importance in both natural ecosystems and agricultural systems, especially in areas where nitrogen availability is limited.