An accidental discharge of organic waste from a dairy farm (containing high concentrations of lactose) enters a slow-flowing stream, causing significant ecological changes downstream.
The graph below shows the changes in lactose concentration, decomposer bacteria, ciliated protozoa, and dissolved oxygen downstream from the discharge point.
Which group of organisms had the most rapid increase in population size shortly after the lactose entered the stream?
- Decomposer bacteria
- Ciliated protozoa
Describe two ways the graph shows a relationship between the decomposer bacteria population and the ciliated protozoa population.
What biological process carried out by the decomposer bacteria causes the concentration of dissolved oxygen to decrease?
Explain why the concentration of dissolved oxygen begins to increase again further downstream as the decomposer bacteria population declines.