Which of these ecosystems has the lowest net primary production per square meter? a. a salt marsh b. an open ocean c. a coral reef d. a tropical rain forest

Verified step by step guidance

1. Understand the concept of Net Primary Production (NPP): NPP is the rate at which all the plants in an ecosystem produce net useful chemical energy; it is equal to the difference between the rate at which the plants in an ecosystem produce useful chemical energy (gross primary production) and the rate at which they use some of that energy during respiration.
2. Recognize the ecosystems listed: a salt marsh, an open ocean, a coral reef, and a tropical rain forest. Each of these ecosystems has different characteristics and biological productivity.
3. Analyze the characteristics of each ecosystem: Salt marshes and tropical rain forests are known for high productivity due to abundant nutrients and favorable climate conditions. Coral reefs, while rich in biodiversity, have moderate productivity. Open oceans, despite covering a large area, have low nutrient availability and thus lower productivity per square meter.
4. Identify the ecosystem with the lowest NPP per square meter: Among the given options, the open ocean has the lowest net primary production per square meter because of its vast area with nutrient-poor waters and less light penetration, which limits photosynthetic activity.
5. Conclude that the correct answer is: b. an open ocean