Primary production

The term primary production referred to in Ecology biomass production by the primary producers, ie plants, cyanobacteria and autotrophic bacteria using light or chemical energy from inorganic substances. The discipline of ecology that deals with the biological production, ie production biology.

The primary production is used as a gross production partly immediately for breathing ( respiration ), remains the net production, which is then used for the growth and proliferation of phytomass. About 1% of the solar radiation which reaches the Earth is converted into biomass. Primary production is the basis for the organic carbon cycle.

In Oceanology and Limnology, this is the production of phytoplankton in the ocean and freshwater, which obtain their energy through photosynthesis, using nutrients. These small green cells are in turn consumed by heterotrophic consumers first order, small animals such as ciliates, copepods and krill. Primary production is the basis of all life in the pelagic, ie agricultural region remote from the oceans.

On the seabed, the marine benthic, such as the black smokers at mid-ocean ridges, there is an ecosystem of its own kind Its base is not photosynthesis, but chemosynthesis, ie the production of energy by decomposition of inorganic compounds such as hydrogen sulfide. There is ultimately the geothermal energy is the source of all life processes, while this is the sun's energy during the process of photosynthesis.

In terrestrial ecosystems, primary production via photosynthesis by plants, such as the trees of the forest. Primary production through chemosynthesis does not matter here.

Productivity is measured in grams dry weight per square meter and year. The highest primary production takes place in the Wadden Sea and in the tropical rain forests.

The primary production is converted for the most part by the consumers and decomposers back to inorganic substances. The surplus is peat and water sludge, resulting in geological time coal and oil produced.

Gross primary production

The gross primary production ( engl. large primary production) is defined as the total, fixed by autotrophic organisms amount of carbon in an ecosystem. This depends on the air, which in turn has an influence on the rate of photosynthesis and leaf area index. The converted energy through photosynthesis, can be used in the plant either respired ( respiration ) or to the growth of the plant. So we subtract the gross primary production of autotrophic respiration from organisms, we obtain the net primary production (NPP ). This represents the whole biomass, which has been obtained from plant by photosynthesis. This biomass also provides a carbon stock in the carbon cycle dar. In the plant, the carbon is used in different ways and to different degrees in different tissues used to thus better adapted to the environmental conditions. Thus one finds in nutrient- poor areas increased allocation of carbon in the roots.

The net primary production is an important indicator of the health of an ecosystem. In addition, it is the most basic source of energy for heterotrophic organisms and strongly linked to the carbon cycle.

Measurement methods

The accurate measurement of the NPP is not possible in nature. But there have been methods developed good estimates may specify. The net primary production can be estimated by measuring the increase in biomass. However, this method is not very accurate and impractical, especially for large and very diverse ecosystems. Where in particular the measurement of the chlorophyll concentration is applied. Chlorophyll has a characteristic spectral signature, which is performed by satellite. It absorbs light in the red and blue spectral range and reflects infrared radiation strongly than water or dry soil. This value can then be made an estimate. A third possibility is because the measurement of gross primary production and respiration. The respiration may be altered by the CO2 concentration, are in a closed system is determined.

The calculation of the net primary production is carried out from the net assimilation rate (NAR ), the leaf area index (LAI ) and the production period ( t). NPP = NAR * LAI * t