Question

The Annual Net Primary Productivity on land and ocean respectively are ________ and ________ billion tons.

• A. 170, 107
• B. 115, 55
• C. 55, 115
• D. 107, 170

Hint:

Always read the requested order carefully! The question asks for Land first, then Ocean. Land = 115, Ocean = 55.

Answer 1

The Correct Option is B

Step 1: Understanding the Problem:
Net Primary Productivity (NPP) is the available biomass produced by photosynthetic organisms. The global NPP is distributed across terrestrial and aquatic ecosystems.
Step 2: Approach and Formula:
Recall the specific global data values for Earth's annual NPP provided in standard ecosystem chapters and calculate the individual distributions.
Step 3: Detailed Explanation:
- The total annual Net Primary Productivity of the entire biosphere is estimated to be approximately 170 billion tons (dry weight) of organic matter.
- Despite covering about 70% of the Earth's surface, the oceans contribute surprisingly little to this total, producing only about 55 billion tons.
- The remainder is produced by the land (terrestrial ecosystems). This is calculated as:
\[ \text{Land NPP} = \text{Total NPP} - \text{Ocean NPP} \] \[ \text{Land NPP} = 170 - 55 = 115 \text{ billion tons} \]
Therefore, the NPP on land is 115 billion tons, and in the ocean, it is 55 billion tons.
Step 4: Final Answer:
The correct option is 115, 55.