Claim · model-written summary
High isoprene emissions were observed at temperatures above 25 degrees C.
- Taxon
- Black Spruce
Picea marianat0 - Treatment
- temperatures above 25°Ce0
- Outcome
- High isoprene emissionse0
- Direction
- Highe0
Not reportedMaterialGeneCompoundOrgan / stageInteractorInteractor roleSecond interactorSecond interactor roleComparatorSettingValueQualifier
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“High isoprene emissions were observed at temperatures above 25°C”
t0“Black Spruce Stand”
Title
E. Pattey; R. L. Desjardins; H. Westberg; et al. Journal of Applied Meteorology 1999. doi:10.1175/1520-0450(1999)038<0870:moieoa>2.0.co;2
Other claims from this paper (11)
- Observation The average isoprene flux over the black spruce stand was 2.29 mg C m-2 h-1 in late July.
- Observation The average isoprene flux decreased to 0.54 mg C m-2 h-1 in early September.
- Mechanism Senescent needles and lower ambient air temperature were most likely the cause of the lower isoprene emissions measured in September.
- Association A relationship of isoprene flux with air temperature was derived at the canopy scale.
- Mechanism The high isoprene emissions at temperatures above 25 degrees C were most likely related to thermoprotection of photosynthesis.
- Method / resource The diurnal trends of isoprene flux measured by gradient transport (GT) and relaxed eddy accumulation (REA) were similar.
- Method / resource Isoprene fluxes measured with GT were 63% lower than those measured with REA.
- Mechanism The GT underestimation resulted from the lower GT inlet being in the roughness sublayer, where flux-gradient relationships are not valid.
- Recommendation Measuring the gradient at about two canopy heights with spacing reduced from 10 to 3 m would reduce the underestimation of the scalar flux.
- Method / resource The reduced gradient spacing would also reduce the isoprene concentration differences by five to six times compared with those obtained with the REA technique.
- Recommendation Boreal zone black spruce should be assigned a standard emission rate of 6 rather than 18 ug C g-1 h-1.