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. Another factor 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, for any reason, it gets disturbed, the entire food chain will be shaken.
Key Takeaways
- NPP (Net Primary Productivity) is the rate at which plants and other photosynthetic organisms convert carbon dioxide into organic matter. At the same time, GPP (Gross Primary Productivity) is the total amount of organic matter produced by photosynthesis.
- NPP considers the amount of organic matter consumed by respiration, while GPP does not.
- NPP is a more accurate measure of organic matter available to support higher trophic levels. At the same time, GPP is a useful measure of the total carbon fixed by photosynthesis.
NPP vs GPP
Accumulation energy rate is called NPP (Net Primary Production). The respiration process is not included in NPP. It depends on GPP. It does not depend on chlorophyll. Organic energy produced during the process of photosynthesis is called GPP (Gross Primary Production). GPP includes a respiration process. It does not depend on NPP. It depends on chlorophyll.
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 useful chemical energy is used for respiration.
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
| Parameters of Comparison | NPP | GPP |
|---|---|---|
| Definition | It is the rate of accumulation of energy. | It is the total biological productivity. |
| Inclusion of Respiration | The respiration process is excluded. | The respiration process is included. |
| Inter-dependent | It is depended on gross primary production. | It is not dependent on net primary production |
| Chlorophyll content | It is not dependent on Chlorophyll. | It is dependent on Chlorophyll content. |
| Directly Matter to | Consumers | Producers |
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 calculation method is simply subtracting the energy loss due to respiration from GPP (Gross Primary Product).
It depends on several factors, including temperature, humidity, sunlight, etc., present in the environment and is highest in the tropical forest area.
The NPP (Net Primary Product) and the sunlight change from season to season. For example, Canada and Russia have the highest NPP (Net Primary Product) during June and July.
NPP (Net Primary Product) also varies according to geographical locations, such as tropical forests having the highest NPP (Net Primary Product) as compared to 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, is the producer of GPP (Gross Primary Production/Productivity) and is part of the ecosystem.
The calculations of GPP include the energy used in other activities, including respiration energy.
The factor of chlorophyll affects the GPP (Gross Primary Production/Productivity).
The amount of present chlorophyll is directly proportional to the GPP (Gross Primary Production/Productivity), as we know that organic energy production 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 reason, 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
- NPP is Net Primary Production/Productivity, while GPP is Gross Primary Production/Productivity.
- 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.
- NPP (Net Primary Product) does not depend on or is affected by Chlorophyll content, whereas GPP (Gross Primary Production) is completely dependent on chlorophyll.
- Gross Primary Productivity is the total productivity, but NPP (Net Primary Product) is only net productivity.
- 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.
- GPP (Gross Primary Production) is directly linked to the producers, while NPP (Net Primary Product) is directly linked to the consumers.
- https://www.journals.uchicago.edu/doi/abs/10.1086/282523
- https://science.sciencemag.org/content/219/4583/410.abstract
- https://esajournals.onlinelibrary.wiley.com/doi/abs/10.2307/2265518
- https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/1051-0761(1997)007[0882:PGPPIT]2.0.CO;2
- https://www.sciencedirect.com/science/article/pii/S0034425711003786
- https://www.sciencedirect.com/science/article/pii/S0034425712003872
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