What is net community productivity in ecology?
The net community productivity is the difference between gross primary productivity and community respiration .
What is net in ecology?
Ecological Net means a system of specially protected natural areas of different statuses, which combines the functions of conservation and use to ensure the ecological balance.
What is meant by productivity in ecology?
What is Productivity? In ecology, productivity refers to the rate of formation of biomass in the ecosystem. It can also be referred to as the energy accumulated in the plants by photosynthesis.
What is net primary productivity easy definition?
Definition. The amount of carbon retained in an ecosystem (increase in biomass); it is equal to the difference between the amount of carbon produced through photosynthesis (GPP) and the amount of energy that is used for respiration (R). Source. Glossary.
What is an example of net primary productivity?
Plants capture and store solar energy through photosynthesis. During photosynthesis, living plants convert carbon dioxide in the air into sugar molecules they use for food. In the process of making their own food, plants also provide the oxygen we need to breathe.
Why is NPP important?
Why is NPP important? NPP is a measure of plant growth. It provides highly synthesized, quantitative information for sustainable resource management.
Why is GPP and NPP important?
The distinction between gross primary production (GPP), net primary production (NPP), and net ecosystem production (NEP) is critical for understanding the energy balance in plants and in whole ecosystems. Production varies among ecosystems, as well as over time within ecosystems.
What is the key difference between primary productivity and net primary productivity?
Net primary productivity (NPP) is the rate at which all plants in an ecosystem produce net useful chemical energy. While gross primary productivity (GPP) is the rate at which primary producers save and collect biomass for energy conservation.
How do you calculate net primary productivity?
Net Primary Productivity (NPP), or the production of plant biomass, is equal to all of the carbon taken up by the vegetation through photosynthesis (called Gross Primary Production or GPP) minus the carbon that is lost to respiration.
What is net primary productivity quizlet?
net primary production. the available energy in the form of organic material that is available for transfer to the next level of the food chain. This is equal to the gross primary productivity of an organism minus the energy used by that organism. niche. the role an organism has in an ecosystem.
What is primary productivity in biology?
What is Primary Productivity? Primary productivity is the process by which organisms make their own food from inorganic sources. The majority of primary producers are terrestrial plants and microbial life, such as algae.
Which ecosystem has highest net primary productivity?
Coral reef ecosystem has highest gross primary productivity due to availability of large number of autotrophs per unit area.
How do you calculate net ecosystem exchange?
Determining Net Ecosystem Exchange Heterotrophic respiration produces large amounts of carbon that is put into the ecosystem. Hence, net ecosystem exchange is determined by subtracting the amount of carbon produced by heterotrophic respiration from the net primary production.
How do you calculate NEP in ecology?
By applying the component-flux-based approach, NEP was calculated as the incoming GPP flux minus the total ecosystem respiration:(3) NEP = GPP − R eco = GPP − ( R S + R Ste + Br + R F ) where Reco represents the total ecosystem respiration calculated as the sum of RS, RSte+Br and RF, also expressed in g m−2 y−1 of ...
Can net ecosystem productivity be negative?
C Net Ecosystem Production (NEP) Negative values may continue for several decades, depending on the amount of detritus present and the growth rates of planted (Gainesville, Florida) or sprouting trees (Castelporziano, Italy).
What is trophic efficiency?
The trophic efficiency is the efficiency at which mass (or energy) is transferred from one trophic level to the next through predation. The individual efficiency is the efficiency with which a typical individual turns its consumption into somatic growth.
What is gross productivity?
Gross productivity is the amount of energy trapped in organic matter during a specified interval at a given trophic level. The table shows the use of visible sunlight is a cattail marsh. The plants have trapped only 2.2% of the energy falling on them. Photosynthesis. 2.2%.
What is the amount of heat needed to warm 1 kg of water?
A kilocalorie is the amount of heat needed to warm 1 kg of water 1 degree Celsius (°C). Because all of the light trapped in photosynthesisis ultimately released as heat, it makes sense to follow the flow of energy through ecosystems in units of heat.
How much energy does one gram of plant material produce?
One gramof plant material (e.g., stems and leaves), which is largely carbohydrate, yields about 4.25 kcalof energy when burned (or respired).
Do humans depend on net productivity?
Humans, like all heterotrophs, depend upon net productivity for their food both
What is biomass production?
The rate of biomass production is called productivity. The portion of fixed energy, a trophic level passes on to the next trophic level is called production. Productivity in ecosystems is of two kinds, i.e., primary and secondary. Green plants fix solar energy and accumulate it in organic forms as chemical energy.
What is secondary productivity?
Secondary productivity is the productivity of animals and saprobes in ecosystem.
What is net productivity of energy?
Net productivity of energy = Gross productivity — Energy lost in respiration.
What is the total solar energy trapped in the food material by photosynthesis?
The total solar energy trapped in the food material by photosynthesis is referred to as gross primary productivity (GPP). However, a good fraction of gross primary productivity is utilised in respiration of green plants.
How is productivity expressed?
Productivity is a rate function, and is expressed in terms of dry matter produced or energy captured per unit area of land, per unit time. It is more often expressed as energy in calories/cm 2 /yr or dry organic matter in g/m 2 /yr (g/m 2 x 8.92 = lb/acre). Hence, the productivity of different ecosystems can be easily compared.
What are the factors that determine the largeness of primary productivity?
The largeness of primary productivity depends on the photosynthetic capacity of producers and the existing environmental conditions, such as solar radiation, temperature and soil moisture.
What is the most important nutrient limiting nutrient in marine ecosystems?
In deep oceans nutrients often become limiting for productivity. Nitrogen is most important nutrient limiting productivity in marine ecosystems.
What is the NEP of an ecosystem?
The NEP of different ecosystems varies considerably depending on plant species, soil type, and climate. Gross primary production is often controlled by the ability of soil biota to release through decomposition essential nutrients such as N and P to sustain NPP. Figure 12.4 shows the size of various plant, microbial, and soil C and N pools in a hybrid poplar system. The activity of decomposers is required to release a small portion of the large soil N pool for NEP. Forests, including tropical, temperate, and boreal forests, have the largest NEP due to the accumulation of wood. Humid tropical ecosystems in general have the highest GPP of all terrestrial environments despite having a limited essential nutrient pool. They are characterized by high production and decomposition rates, where nutrients are actively cycling through plant litter and soil biota, and less storage in soil as organic matter. Optimal temperature and moisture conditions for decomposition prevail in humid tropical environments, leading to relatively closed nutrient cycles in the absence of disturbance. In northern latitude ecosystems, lower temperatures lead to slower decomposition of plant litter. The accumulation of plant matter in forest floor litter layers can withhold from the soil solution essential nutrients, particularly N. Disturbance such as fire, a physical oxidative decomposition process, is often required to release nutrients to increase NPP. Plant community succession also leads to changes in nutrient cycling through changes in the quantity and quality of litter inputs or the nutrient requirements of succeeding plant and microbial communities.
What is the process of photosynthesis?
Photosynthesis converts inorganic C (CO 2) into organic C through gross primary production (GPP) ( Fig. 12.3 ). Some of this carbon is returned to the atmosphere as plant-respired CO 2; the remainder becomes plant biomass and is termed net primary production (NPP). Free-living autotrophic microbes, such as algae, also contribute to GPP and NPP. Net secondary production (NSP) is the consumption of NPP by fauna and microorganisms. The standing stock of C in an ecosystem is defined as GPP less the respiratory loss of autotrophs (photosynthesizers) and decomposers (heterotrophs) and is termed net ecosystem production (NEP). Free-living microorganisms and soil fauna consume (decompose) the majority of NPP. The process of decomposition occurs on the order of days to decades and is dependent on environmental conditions and the quality of the plant material entering the soil. The selective preservation of some resistant plant constituents, such as lignin, and the activity of microorganisms produce precursors to humic substances described later in this chapter. Soil humic substances can persist for thousands of years and are important stable C pools making up two-thirds of terrestrial C stores. GPP, NPP, NSP, and NEP are processes usually measured in terms of g C m −2 year −1 or similar units.
How much does attached algae contribute to NPP?
In the littoral zone of Lake Mikolajskie, Poland attached algae contributed 41% to annual NPP per m 2, submersed macrophytes 28%, Metaphyton 21% and phytoplankton 10%. In a littoral zone overgrown with emergent vegetation, the contribution was almost twice as high from macrophytes (57.2%) and phytoplankton (19.6%), the share from attached algae decreased to 23.1% and metaphyton dropped to a negligible amount of only 0.1%.
How is soil efflux measured?
Soil efflux was measured at the same time as NEP using a Li-Cor 6400 portable photosynthesis machine with the soil chamber. The soil chamber fits inside a PVC soil collar, which was placed in the plot at least 2 weeks prior to the first measurement. Soil efflux was measured in two places in each plot along the gradient and one place per plot for the manipulation.
How to calculate NEP?
NEP can be calculated using different methods including long-term continuous records of dissolved oxygen or inorganic carbon (relative to saturation concentrations) at diel or seasonal scales ( e.g., Howarth et al. , 1992 ), and summation of individual production and respiration measurements broadly representing temporal and spatial scales and major habitats ( e.g., Kemp et al., 1997 ). NEP can also be computed using estimates of the net balance between imports and exports of DIP (e.g., Smith, 1991 ), where rates are converted from phosphorus to carbon units assuming a fixed stoichiometry for primary production and nutrient recycling (e.g., C:N:P = 106:16:1). Conversely, NEP can be converted to nitrogen units using these stoichiometric assumptions; however, the net balance of DIN will also be affected by two important processes involving nitrogen gas production and consumption—denitrification and nitrogen fixation, respectively (e.g., Nixon and Pilson, 1984 ). In fact, rates of NEP and related biogeochemical fluxes have been estimated for many estuaries and coastal bays worldwide combining simple water- and salt-balance models that compute advective and diffusive solute transport with data for DIN and DIP time-space distributions to infer non-conservative net fluxes as residuals in dynamic nutrient budget calculations ( http://wwwold.nioz.nl/loicz/ ). Comparative analyses of these rates suggest broad regional relationships with hydrology and watershed development ( Smith et al., 2003 ).
What are the most productive macrophytes in the littoral?
Emergent plants are the most productive macrophytes in the littoral ( Table 6 ). Floating leaved plants are intermediate and submersed macrophytes are the least productive macrophytes among the higher plants in the littoral. In oligotrophic lakes, the algal class of the Charophytes (stoneworts) often is more productive than the submersed vegetation. Littoral productivity increases 3–5 times when lakes become eutrophic. Since macrophyte biomass in the littoral is high and turnover slow (P/B < 1) nutrients are less readily available in the littoral region. Macrophyte beds buffers the pelagic zone. In general, the littoral is more defined by biomass than turnover.
What are the three major reservoirs of carbon?
There are only three major reservoirs with exchange rates fast enough to vary significantly on the time scale of decades to centuries: the atmosphere, the terrestrial biosphere , and the oceans . Of this three-component system, approximately 93% of the carbon is located in the oceans. The atmosphere, at about 750 Pg C (1 Pg10 15 g), has the smallest total pool of carbon. The annual atmospheric exchange of CO 2 with both the oceans and the terrestrial biosphere is on the order of 80–130 Pg C y −1. Although these fluxes are very large, the mass of carbon in each of these reservoirs may not change over time. Ice core records suggest that the atmospheric CO 2 concentrations were very close to 280 ppm for the 1000 years prior to the industrial era (see Figure 1 ). This constancy suggests that the carbon pools were more or less in equilibrium, and the net transfer over sufficiently large areas was close to zero.
What is biomass used for?
3.The biomass generated is used for the cellular respiration of plants which it converts into nutrients and ATP necessary for cell production. GPP is used for cell production while NPP is the difference between the GPP and cellular respiration.
What is the rate of how an ecosystem’s producers or autotrophs collect and save a certain amount of chemical?
Gross Primary Productivity (GPP) is the rate of how an ecosystem’s producers or autotrophs collect and save a certain amount of chemical energy referred to as biomass at a specific time. Biomass energy can be used for chemical, thermal, and biochemical conversion.
What is the net primary productivity?
The excess or loss generated from this process is the Net Primary Productivity (NPP). It is the difference between how much useful chemical energy is produced by plants in the ecosystem in relation to how a portion of that energy is used for cellular respiration. NPP is used to assess the function of the ecosystem and the effects of climate change on it, to monitor the health of plants and changes in productivity over time, and to estimate the yield of a crop.
What are the primary producers?
Primary producers or autotrophs form the base for the food chain, and they produce food for other organisms. Primary producers include marine algae, land plants, and bacteria. They are involved in the processes of photosynthesis and chemosynthesis. Primary production may either be Gross Primary Productivity or Net Primary Productivity.
What is productivity in ecology?
In ecology, productivity refers to the rate of biomass generation in an ecosystem. It is the proportion of units of mass per unit of volume or surface per units of time. In plants, productivity is determined through the synthesis of organic materials from inorganic molecules into simpler organic compounds. This process is also called “primary ...
What is the difference between GPP and NPP?
1.“GPP” stands for “Gross Primary Productivity” while “NPP” stands for “Net Primary Productivity.”. 2.GPP is the rate an ecosystem’s primary producers collect and save biomass in a specified time for chemical, thermal, and biochemical conversion while NPP is the rate of loss or excess that is generated by the process.
How has the human burden on the ecosystem affected the future?
In several areas of the world, land is so parched that no plant can survive, and the Earth’s climate has been greatly affected by climate change and by global warming which is in part caused by man. Summary:
