Here's a problem to solve: Many fertilizers contain organic materials that are helpful to an orchard but have a different effect when rain causes them to run off into a freshwater ecosystem. How does the addition of organic waste from fertilizers most commonly affect freshwater ecosystems?

Among the 4 following options, which is the correct answer?

- A: increasing biodiversity
 
- B: increasing water clarity
 
- C: decreasing algae blooms
 
- D: decreasing oxygen levels
 