Primary productivity is basically the productivity of organic compounds using raw materials, carbon dioxide and energy.Primary production occurs everywhere on the Earth, be it chemo-synthesis or photosynthesis. The only requirement for primary productivity is energy source. The main difference between gross primary productivity and net primary productivity is, gross primary productivity is the complete amount of food generated and net primary productivity is difference between GPP and the quantity of food used by producers for respiration.
Gross Primary Productivity
GPP is the rate at which ecosystem’s producers store and capture provided amount of energy as biomass in a given time duration. Moreover, it is expressed in mass of food in a given territory or given volume. So, gross primary productivity is the full amount of food produced by the producer. It depends of chlorophyll content. Productivity is about new energy entering the ecosystem and even about new matter and some of the energy produces by GPP is used in respiration at cellular level, development and growth of the plant.
Net Primary Productivity
The loss of energy which is generated from the process of GPP, is termed as net primary productivity. NPP is the difference between useful energy which is produced by plants to how that portion of energy is used in cellular respiration. The climate change on an ecosystem and the actual functioning of an ecosystem can be determined by NPP. Moreover, we can use NPP to evaluate the well being of plants and their functioning. NPP is also used in various sectors to calculate the yield of crop. NPP could be affected by various factors like climatic changes, water availability, soil quality, nutrients , environment and many more.
- GPP stands for gross primary productivity and NPP stands for net primary productivity.
- NPP is defined as the loss or excess of energy which is generated by the process while GPP is the rate at which primary producers save and collect biomass for energy conversion.
- NPP is the difference between GPP and cellular respiration. On the other hand, GPP is used for cell production.
- GPP depends on chlorophyll content while NPP does not depend upon chlorophyll content.
- GPP refers to total productivity and NPP is the net productivity, converted to organic matter.
- GPP could affect NPP but NPP cannot affect GPP.
- GPP directly matters for producers while NPP directly matters for consumers.
- In terms of food, NPP is the basic driving force of life.