Difference Between NPP and GPP (With Table)

The primary productivity is the speed at which the energy (sunlight) is converted into organic matter by using chlorophyll. The two main factors that affect primary production are light and nutrients. Other factors that can lead to a decrease in Primary production can be water. 

A decrease in any of these factors can cause a decrease in the level of Primary Production. The process of primary production must take place as it is the base or foundation of the food chain. Therefore if due to any reason it gets disturbed, the entire food chain will be shaken.

NPP vs GPP

The difference between NPP (Net primary production) and GPP (Gross primary production) is that NPP (Net primary production) is the energy fixed by autotroph and their respiration, whereas GPP (Gross primary production) is the total biological productivity of an ecosystem. Both of them are different in terms of dependency on chlorophyll and terms of consumer and producer. NPP (Net primary production) is affected and calculated by the GPP (Gross primary production).

NPP stands for net primary production. It is defined as the rate at which every autotroph which is included in the ecosystem produces net chemical energy. It is the difference between the rate of total useful chemical energy produced and the rate at which some of its useful chemical energy is used for the respiration process.  

GPP stands for Gross primary production. It is defined as the rate at which every autotroph which is included in the ecosystem produces useful chemical energy. The amount of chemical energy produced by the primary producers, i.e., autotrophs, which are also known as carbon biomass in a given period is also can be termed as GPP.  

Comparison Table Between NPP and GPP

Parameters of ComparisonNPPGPP
DefinitionIt is the rate of accumulation of energy.It is the total biological productivity.
Inclusion of RespirationThe respiration process is excluded.The respiration process is included.
Inter-dependentIt is depended on gross primary production.It is not dependent on net primary production
Chlorophyll contentIt is not dependent on Chlorophyll.It is dependent on Chlorophyll content.
Directly Matter toConsumersProducers

What is NPP?

It is the rate of accumulation of energy (biomass). Photosynthesis is the process through which plants make organic matter by using sunlight. The organic matter made during the product does not use the entire energy stored. One-fourth of the energy is used for other biological processes. 

NPP (Net Primary Product) does not include all these losses but only includes the organic matter that is contributed to the food web. Another way of calculation is by simply subtracting the energy loss due to respiration from GPP (Gross Primary Product). It is dependent on several factors that include temperature, humidity, sunlight, etc., present in the environment and is highest in the tropical forest area.

The NPP (Net Primary Product) changes from season to season along with the sunlight. For example, Canada and Russia have the highest NPP (Net Primary Product) during June and July. 

NPP (Net Primary Product) also varies according to the geographical locations, such as tropical forests have the highest NPP (Net Primary Product) as compared to the deserts. Next trophic level organisms are the direct consumer of NPP (Net Primary Product). The calculations of NPP are done in the units- mass per area per unit of time.

What is GPP?

GPP (Gross Primary Production/Productivity) is defined as the measure of the total amount of produced organic energy using sunlight from the producers within an area. It is produced during the process of photosynthesis. Every autotroph in the environment which is considered for the measurement and calculation are the producers of GPP (Gross Primary Production/Productivity) and are the part of the ecosystem. The calculations of GPP include the energy which is used in other activities, including respiration energy too.

The GPP (Gross Primary Production/Productivity) is highly affected by the factor of chlorophyll. The amount of present chlorophyll is directly proportional to the GPP (Gross Primary Production/Productivity) as we know that the production of organic energy is only possible during photosynthesis. The GPP (Gross Primary Production/Productivity) can also affect the NPP (Net Primary Product) of an area as NPP (Net Primary Product) is completely dependent on the GPP (Gross Primary Production/Productivity). 

If the GPP (Gross Primary Production/Productivity) is decreased because of any reasons, The NPP (Net Primary Product) will also be decreased in the same manner. GPP (Gross Primary Production/Productivity) is dependent on the producers.

Main Differences Between NPP and GPP

  1. NPP is Net Primary Production/Productivity while GPP is Gross Primary Production/Productivity.
  2. NPP (Net Primary Product) is calculated by excluding the respiration by plants from the GPP (Gross Primary Production) whereas GPP (Gross Primary Production) is for cell production; therefore, GPP (Gross Primary Production) includes respiration energy too.
  3. NPP (Net Primary Product) does not depend on or affected by Chlorophyll content, whereas GPP (Gross Primary Production) is completely dependent on chlorophyll.
  4. Gross Primary Productivity is the total productivity, but NPP (Net Primary Product) is only net productivity.
  5. As NPP (Net Primary Product) is calculated from the GPP (Gross Primary Production), therefore GPP (Gross Primary Production) affects the NPP (Net Primary Product), but in the case of GPP (Gross Primary Production), NPP (Net Primary Product) does not affect it at all.
  6. GPP (Gross Primary Production) is directly linked to the producers, while NPP (Net Primary Product) is directly linked to the consumers.

Conclusion

To build the records and for having the comparisons, some way of measurements are required to establish in such a way that they can be universal, useful, and can provide important information. Same way, for the measurement of the production of energy, organic energy to be specified, GPP(Gross Primary Production) and NPP(Net Primary Product) are established so that they can be measured and research over them can be continued and can reach advanced levels. 

The basic example proving that these measurements help in research is after examining the productions of energies, many factors that affect them are determined. So GPP (Gross Primary Production) is different still similar to NPP (Net Primary Product) and helps in the research and comparison stuff to the interested ones.

References

  1. https://www.journals.uchicago.edu/doi/abs/10.1086/282523
  2. https://science.sciencemag.org/content/219/4583/410.abstract
  3. https://esajournals.onlinelibrary.wiley.com/doi/abs/10.2307/2265518
  4. https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/1051-0761(1997)007[0882:PGPPIT]2.0.CO;2
  5. https://www.sciencedirect.com/science/article/pii/S0034425711003786
  6. https://www.sciencedirect.com/science/article/pii/S0034425712003872
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