Related Experiment Video
Updated: Jul 2, 2026
09:05
Measurements of CO2 Fluxes at Non-Ideal Eddy Covariance Sites
Published on: June 24, 2019
Global potential net primary production predicted from vegetation class, precipitation, and temperature
Stephen Del Grosso1, William Parton, Thomas Stohlgren
1Agricultural Research Service, US Department of Agriculture, Fort Collins, Colorado 80526, USA. delgro@nrel.colostate.edu
Ecology
|August 30, 2008
Summary
A new model estimates global Net Primary Production (NPP), crucial for the carbon cycle. It uses climate and land cover data, improving accuracy for different ecosystems like forests and grasslands.
Area of Science:
- Ecology
- Biogeochemistry
- Climate Science
Background:
- Net Primary Production (NPP) is a key component of the global carbon cycle, representing the balance between photosynthesis and respiration.
- Accurate estimation of global NPP is vital for understanding ecosystem function and climate change impacts.
- Existing empirical models often overestimate NPP in non-tree-dominated systems.
Purpose of the Study:
- To develop a simple regression model for estimating global NPP using readily available climate and land cover data.
- To improve the accuracy of NPP estimations, particularly for non-tree-dominated ecosystems.
- To provide updated estimates of global NPP for the late 20th century and assess changes over time.
Main Methods:
- Compiled approximately 5600 global data points including observed NPP, land cover, precipitation, and temperature.
- Developed a new regression model (NCEAS model) differentiating between tree-dominated and non-tree-dominated systems.
- Validated model performance by comparing precipitation and temperature correlations with NPP across different land cover types.
Main Results:
- Precipitation was a stronger predictor of NPP than temperature, especially for grass/shrub systems (r2 = 0.68).
- Tree-dominated systems exhibited significantly higher NPP than non-tree systems at similar precipitation levels.
- The NCEAS model accurately estimated NPP for tree systems using precipitation and temperature, while relying solely on precipitation for non-tree systems to minimize error.
Conclusions:
- The NCEAS model provides more accurate global NPP estimates by accounting for land cover differences.
- Estimated late 20th-century global aboveground and total NPP at approximately 28 Pg and 46 Pg C/yr, respectively.
- The model indicated a ~13% increase in global NPP from 1901-2000 due to changing climate patterns.
Related Concept Videos
01:06Primary Production
The total amount of energy acquired by primary producers in an ecosystem is called gross primary production (GPP). However, of this energy, producers use some for metabolic processes, and some is lost as heat, decreasing the amount of energy available to the next trophic level. The remaining usable amount of energy is called the net primary productivity (NPP). In terrestrial ecosystems, NPP is driven by climate, while light penetration and nutrient availability drive NPP in aquatic ecosystems.
01:17Precipitation and Co-precipitation
Precipitation and coprecipitation methods can be used to separate a mixture of ions in a solution. In qualitative inorganic analysis, ions that form sparingly soluble precipitates with the same reagent are separated based on the differences in solubility products. For example, consider the separation of Cu(II) and Fe(II) ions by precipitation as insoluble sulfides. First, copper(II) sulfide is precipitated by the addition of acidic H2S, where the dissociation of H2S is suppressed. Adding H2S...
01:12Precipitation Processes
The experimental conditions in a gravimetric analysis should be optimized to maximize the particle size and purity of the obtained precipitate. Ideally, the concentration of the precipitating reagent should be low with effective stirring to maintain low relative supersaturation for the growth of large crystals. In homogeneous precipitation, the precipitant is slowly generated by a chemical reaction in the solution to avoid local reagent excesses. For example, urea decomposes gradually to...
01:03Precipitation Gravimetry
Precipitation gravimetry is based on converting an analyte into a sparingly soluble precipitate, which is separated by filtration and weighed. An ideal precipitate should be pure, insoluble, of known composition, and easily filtered from the reaction mixture.
In determining nickel by gravimetric analysis, a precipitant of ethanolic dimethylglyoxime is added to a hot nickel salt solution. This is quickly followed by the dropwise addition of dilute ammonia solution until precipitation occurs. A...
In determining nickel by gravimetric analysis, a precipitant of ethanolic dimethylglyoxime is added to a hot nickel salt solution. This is quickly followed by the dropwise addition of dilute ammonia solution until precipitation occurs. A...
01:01Production Efficiency
Net production efficiency (NPE) is the efficiency at which organisms assimilate energy into biomass for the next trophic level. Due to low metabolic rates and less energy spent on thermoregulatory processes, the NPE of ectotherms (cold-blooded animals) is 10 times higher than endotherms (warm-blooded animals).
01:50Global Climate Change
Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.