Respiration ecosystem

Our understanding of seasonal and interannual variation in global terrestrial vegetation dynamics is, however, very sketchy at present. Ecosystem respiration measurements have been made for various soil-vegetation types for variable lengths of time Relationships between ecosystem respiration and weather data have been derived from these data for four major biomes 88), However, additional systematic collection of field respiration measurements would be necessary for placing much confidence in such a relationship. 

The concentration and flux of dissolved organic carbon (DOC) are important characteristics of aquatic ecosystems, with important effects on light and ultraviolet (UV)-B attenuation, ecosystem respiration, nutrient... 

Net primary production (NPP) is the total carbon fixed minus the amount respired only by the primary producers (Ra). Net ecosystem production (NEP) is derived from the difference between GPP and ecosystem respiration (R), which includes both heterotrophic and autotrophic processes. 

Net ecosystem production the difference between GPP and ecosystem respiration (R), which includes both heterotrophic and autotrophic processes. 

Howarth, R. W., Marino, R., Garritt, R., and Sherman, D. (1992). Ecosystem respiration and organic carbon processing in a large, tidaUy influenced river The Hudson River. Biogeochemistry 16, 83-102. 

For the atmospheric budget (Equation (12)) an estimate that integrates the 6 C value of ecosystem respiration is required. Autotrophic respiration values may be reasonably... 

C. (2001) Ecosystem respiration response to warming and water-table manipulations in peatland mesocosms. Ecol. Appl. 11, 311-326. 

As NEP is often small relative to the gross fluxes of photosynthesis and ecosystem respiration, the net flux is sometimes less than the error of measurement. More important than error is bias, and the approach is vulnerable to bias because both the fluxes of CO2 and the micro-meteorological conditions are systematically different day and night. Wind speeds below 17 cm s in a temperate zone forest, e.g., resulted in an underestimate of nighttime respiration (Barford et al., 2001). A similar relationship between nighttime wind speed and respiration in forests in the Brazilian Amazon suggests that the assumption that lateral transport is unimportant may have been invalid (Miller et al., in press). 

TABLE 3 Glolxil Me ins for C Signiiuires of Ecosystem Respiration 8" C,and Biospheric Discrimination A Estimates... 

Ehleringer, J. R. and Cook, C. S. (1998). Carbon and oxygen isotope ratios of ecosystem respiration along an Oregon conifer transect Preliminary observations based upon small-flask sampling. Tree Physiol. 18, 513-519. 

Lafleur, P. M., T. R. Moore, N. T. Roulet, and S. Frolking. 2005. Ecosystem respiration in a cool temperate bog depends on peat temperatme but not water table. Ecosystems 8 619-629. 

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