NET PRIMARY PRODUCTIVITY'T IN A FRESHWATER POND ECOSYSTEM DURING SPRING Net Primary Productivity O 10 20 30 140 Depth of Water ( meters )

Consumers in aquatic ecosystems depend on producers for nutrition.

a. Explain the difference between gross and net primary productivity.

b. Describe a method to determine net and gross primary productivity in a freshwater pond over a 24-hour period. 

In an experiment, net primary productivity was measured, in the early spring, for water samples taken from different depths of a freshwater pond in a temperate deciduous forest.

c. Explain the data presented by the graph, including a description of the relative rates of metabolic processes occurring at different depths of the pond.

d. Describe how the relationship between net primary productivity and depth would be expected to differ if new data were collected in midsummer from the same pond. Explain your prediction.

NET PRIMARY PRODUCTIVITY'T IN A FRESHWATERPOND ECOSYSTEM DURING SPRINGNet Primary ProductivityO10 20 30140Depth of Water ( meters )