-What is dissolved oxygen (DO), and why is it important for aquatic ecosystems?

-What are the factors that can affect the level of dissolved oxygen (DO), and how do they affect it?

-What are the main sources of dissolved oxygen in natural water bodies, and how do the oxygen particles enter the water bodies?

-How do human activities impact dissolved oxygen levels in water?

-What is hypoxia, and what causes it in aquatic environments?

-How does water stratification affect dissolved oxygen distribution?

-What are some common methods used to measure dissolved oxygen levels?

Why do fish and other aquatic organisms require a minimum level of DO to survive?

What are some potential consequences of low dissolved oxygen levels in water bodies?