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NEETBotanyEcosystem

In an aquatic ecosystem, the total rate at which solar energy is captured by phytoplankton during photosynthesis is reduced by the energy utilised for their own respiration. The remaining biomass, which is available for consumption by zooplankton, is termed as 'X' and is typically measured in units of 'Y'. Select the correct option for X and Y.

Options

  1. AX = Gross Primary Productivity ; Y = g , m ⁻² , yr ⁻¹
  2. BX = Net Primary Productivity ; Y = g , m ⁻²
  3. CX = Net Primary Productivity ; Y = kcal , m ⁻² , yr ⁻¹
  4. DX = Secondary Productivity ; Y = kcal , m ⁻² , yr ⁻¹

Correct answer

C. X = Net Primary Productivity ; Y = kcal , m ⁻² , yr ⁻¹

Step-by-step solution

The total rate of production of organic matter during photosynthesis is called Gross Primary Productivity (GPP). A considerable amount of GPP is utilised by producers (phytoplankton) in respiration (R). The remaining biomass, which is available for consumption by heterotrophs (like zooplankton), is called Net Primary Productivity (NPP). Thus, NPP = GPP - R. Since NPP is a rate of production (productivity), it must be expressed with both an area and a time dimension. Its standard units are g , m ⁻² , yr ⁻¹ or kcal ,

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