Question

Which of these ecosystems has the lowest primary productivity per square meter?

Options

• Salt marsh

• Open ocean

• Grassland

• Tropical forest

Answer 1

Open ocean

Explanation:

The open ocean has the lowest primary productivity per square meter because it has limited nutrient availability, which restricts the growth of phytoplankton, the leading primary producers. Despite its vast area, primary productivity per unit area is low compared to nutrient-rich ecosystems such as salt marshes, grasslands, or tropical forests, which have abundant nutrients and dense vegetation, leading to higher productivity per square meter.