Isoprene emission by poplar is not important for the feeding behaviour of poplar leaf beetles
Müller, A. ; Kaling, M. ; Faubert, P. ; Gort, G. ; Smid, H.M. ; Loon, J.J.A. van; Dicke, M. ; Kanawati, B. ; Schmitt-Kopplin, P. ; Polle, A. ; Schnitzler, J.P. ; Rosenkranz, M. - \ 2015
BMC Plant Biology 15 (2015)1. - ISSN 1471-2229 - 16 p.
organic-compound emissions - chrysomela-populi - phratora-vitellinae - plant interactions - emitting poplars - volatiles - biosynthesis - caterpillars - performance - trichocarpa
Background Chrysomela populi (poplar leaf beetle) is a common herbivore in poplar plantations whose infestation causes major economic losses. Because plant volatiles act as infochemicals, we tested whether isoprene, the main volatile organic compound (VOC) produced by poplars (Populus x canescens), affects the performance of C. populi employing isoprene emitting (IE) and transgenic isoprene non-emitting (NE) plants. Our hypothesis was that isoprene is sensed and affects beetle orientation or that the lack of isoprene affects plant VOC profiles and metabolome with consequences for C. populi feeding. Results Electroantennographic analysis revealed that C. populi can detect higher terpenes, but not isoprene. In accordance to the inability to detect isoprene, C. populi showed no clear preference for IE or NE poplar genotypes in the choice experiments, however, the beetles consumed a little bit less leaf mass and laid fewer eggs on NE poplar trees in field experiments. Slight differences in the profiles of volatile terpenoids between IE and NE genotypes were detected by gas chromatography - mass spectrometry. Non-targeted metabolomics analysis by Fourier Transform Ion Cyclotron Resonance Mass Spectrometer revealed genotype-, time- and herbivore feeding-dependent metabolic changes both in the infested and adjacent undamaged leaves under field conditions. Conclusions We show for the first time that C. populi is unable to sense isoprene. The detected minor differences in insect feeding in choice experiments and field bioassays may be related to the revealed changes in leaf volatile emission and metabolite composition between the IE and NE poplars. Overall our results indicate that lacking isoprene emission is of minor importance for C. populi herbivory under natural conditions, and that the lack of isoprene is not expected to change the economic losses in poplar plantations caused by C. populi infestation.
Summertime total OH reactivity measurements from boreal forest during HUMPPA-COPEC 2010
Nölscher, A.C. ; Williams, J. ; Sinha, V. ; Custer, T. ; Song, W. ; Ouwersloot, H.G. ; Vilà-Guerau de Arellano, J. - \ 2012
Atmospheric Chemistry and Physics 12 (2012). - ISSN 1680-7316 - p. 8257 - 8270.
organic-compound emissions - scots pine - ptr-ms - tropical forest - ambient air - isoprene - model - temperature - humppa-copec-2010 - degradation
Ambient total OH reactivity was measured at the Finnish boreal forest station SMEAR II in Hyyti¨al¨a (Latitude 61510 N; Longitude 24170 E) in July and August 2010 using the Comparative Reactivity Method (CRM). The CRM – total OH reactivity method – is a direct, in-situ determination of the total loss rate of hydroxyl radicals (OH) caused by all reactive species in air. During the intensive field campaign HUMPPA-COPEC 2010 (Hyyti¨al¨a United Measurements of Photochemistry and Particles in Air – Comprehensive Organic Precursor Emission and Concentration study) the total OH reactivity was monitored both inside (18 m) and directly above the forest canopy (24 m) for the first time. The comparison between these two total OH reactivity measurements, absolute values and the temporal variation have been analyzed here. Stable boundary layer conditions during night and turbulent mixing in the daytime induced low and high short-term variability, respectively. The impact on total OH reactivity from biogenic emissions and associated photochemical products was measured under “normal” and “stressed” (i.e. prolonged high temperature) conditions. The advection of biomass burning emissions to the site caused a marked change in the total OH reactivity vertical profile. By comparing the OH reactivity contribution from individually measured compounds and the directly measured total OH reactivity, the size of any unaccounted for “missing” sink can be deduced for various atmospheric influences. For “normal” boreal conditions a missing OH reactivity of 58 %, whereas for “stressed” boreal conditions a missing OH reactivity of 89% was determined. Various sources of not quantified OH reactive species are proposed as possible explanation for the high missing OH reactivity.
The global chemistry transport model TM5: description and evaluation of the tropospheric chemistry version 3.0
Huijnen, V. ; Williams, J. ; Weele, M. van; Noije, T. van; Krol, M.C. ; Dentener, F. ; Segers, A. ; Houweling, S. ; Peters, W. - \ 2010
Geoscientific Model Development 3 (2010)2. - ISSN 1991-959X - p. 445 - 473.
general-circulation model - dry deposition parameterization - organic-compound emissions - mozaic airborne program - gas-phase reactions - air-quality models - interannual variability - atmospheric chemistry - photochemical data - tracer transport
We present a comprehensive description and benchmark evaluation of the tropospheric chemistry version of the global chemistry transport model TM5 (Tracer Model 5, version TM5-chem-v3.0). A full description is given concerning the photochemical mechanism, the interaction with aerosol, the treatment of the stratosphere, the wet and dry deposition parameterizations, and the applied emissions. We evaluate the model against a suite of ground-based, satellite, and aircraft measurements of components critical for understanding global photochemistry for the year 2006. The model exhibits a realistic oxidative capacity at a global scale. The methane lifetime is ~8.9 years with an associated lifetime of methyl chloroform of 5.86 years, which is similar to that derived using an optimized hydroxyl radical field. The seasonal cycle in observed carbon monoxide (CO) is well simulated at different regions across the globe. In the Northern Hemisphere CO concentrations are underestimated by about 20 ppbv in spring and 10 ppbv in summer, which is related to missing chemistry and underestimated emissions from higher hydrocarbons, as well as to uncertainties in the seasonal variation of CO emissions. The model also captures the spatial and seasonal variation in formaldehyde tropospheric columns as observed by SCIAMACHY. Positive model biases over the Amazon and eastern United States point to uncertainties in the isoprene emissions as well as its chemical breakdown. Simulated tropospheric nitrogen dioxide columns correspond well to observations from the Ozone Monitoring Instrument in terms of its seasonal and spatial variability (with a global spatial correlation coefficient of 0.89), but TM5 fields are lower by 25–40%. This is consistent with earlier studies pointing to a high bias of 0–30% in the OMI retrievals, but uncertainties in the emission inventories have probably also contributed to the discrepancy. TM5 tropospheric nitrogen dioxide profiles are in good agreement (within ~0.1 ppbv) with in situ aircraft observations from the INTEX-B campaign over (the Gulf of) Mexico. The model reproduces the spatial and seasonal variation in background surface ozone concentrations and tropospheric ozone profiles from the World Ozone and Ultraviolet Radiation Data Centre to within 10 ppbv, but at several tropical stations the model tends to underestimate ozone in the free troposphere. The presented model results benchmark the TM5 tropospheric chemistry version, which is currently in use in several international cooperation activities, and upon which future model improvements will take place
The impact of Future Land Use and Land Cover Changes on Atmospheric Chemistry-Climate Interactions
Ganzeveld, L.N. ; Bouwman, L. - \ 2010
Journal of Geophysical Research: Atmospheres 115 (2010)D23. - ISSN 2169-897X - 18 p.
general-circulation model - organic-compound emissions - isoprene emissions - technical note - dry deposition - sres scenarios - ozone - surface - echam5/messy1 - exchanges
To demonstrate potential future consequences of land cover and land use changes beyond those for physical climate and the carbon cycle, we present an analysis of large-scale impacts of land cover and land use changes on atmospheric chemistry using the chemistry-climate model EMAC (ECHAM5/MESSy Atmospheric Chemistry) constrained with present-day and 2050 land cover, land use, and anthropogenic emissions scenarios. Future land use and land cover changes are expected to result in an increase in global annual soil NO emissions by ~1.2 TgN yr-1 (9%), whereas isoprene emissions decrease by ~50 TgC yr-1 (-12%). The analysis shows increases in simulated boundary layer ozone mixing ratios up to ~9 ppbv and more than a doubling in hydroxyl radical concentrations over deforested areas in Africa. Small changes in global atmosphere-biosphere fluxes of NOx and ozone point to compensating effects. Decreases in soil NO emissions in deforested regions are counteracted by a larger canopy release of NOx caused by reduced foliage uptake. Despite this decrease in foliage uptake, the ozone deposition flux does not decrease since surface layer mixing ratios increase because of a reduced oxidation of isoprene by ozone. Our study indicates that the simulated impact of land cover and land use changes on atmospheric chemistry depends on a consistent representation of emissions, deposition, and canopy interactions and their dependence on meteorological, hydrological, and biological drivers to account for these compensating effects. It results in negligible changes in the atmospheric oxidizing capacity and, consequently, in the lifetime of methane. Conversely, we expect a pronounced increase in oxidizing capacity as a consequence of anthropogenic emission increases
Coupled carbon-water exchange of the Amazon rain forest. II. Comparison of predicted and observed seasonal exchange of energy, CO2, isoprene and ozone at a remote site in Rondônia
Simon, E. ; Meixner, F.X. ; Rummel, U. ; Ganzeveld, L.N. ; Ammann, C. ; Kesselmeier, J. - \ 2005
Biogeosciences 2 (2005)3. - ISSN 1726-4170 - p. 255 - 275.
atmospheric boundary-layers - organic-compound emissions - dry deposition - tropical forest - monoterpene emission - growth-conditions - temperate forest - deciduous forest - gas-exchange - model
A one-dimensional multi-layer scheme describing the coupled exchange of energy and CO2, the emission of isoprene and the dry deposition of ozone is applied to a rain forest canopy in southwest Amazonia. The model was constrained using mean diel cycles of micrometeorological quantities observed during two periods in the wet and dry season 1999. Calculated net fluxes and concentration profiles for both seasonal periods are compared to observations made at two nearby towers. The modeled day- and nighttime thermal stratification of the canopy layer is consistent with observations in dense canopies. The observed and modeled net fluxes above and H2O and CO2 concentration profiles within the canopy show a good agreement. The predicted net carbon sink decreases from 2.5 t C ha-1 yr-1 for wet season conditions to 1 t C ha-1 yr-1 for dry season conditions, whereas observed and modeled midday Bowen ratio increases from 0.5 to 0.8. The evaluation results confirmed a seasonal variability of leaf physiological parameters, as already suggested in a companion study. The calculated midday canopy net flux of isoprene increased from 7.1 mg C m-2 h-1 during the wet season to 11.4 mg C m-2 h-1 during the late dry season. Applying a constant emission capacity in all canopy layers, resulted in a disagreement between observed and simulated profiles of isoprene concentrations, suggesting a smaller emission capacity of shade adapted leaves and deposition to the soil or leaf surfaces. Assuming a strong light acclimation of emission capacity, equivalent to a 66% reduction of the standard emission factor for leaves in the lower canopy, resulted in a better agreement of observed and modeled concentration profiles and a 30% reduction of the canopy net flux compared to model calculations with a constant emission factor. The mean calculated ozone flux for dry season conditions at noontime was ˜12 n mol m-2 s-1, agreeing well with observed values. The corresponding deposition velocity increased from 0.8 cm s-1 to >1.6 cm s-1 in the wet season, which can not be explained by increased stomatal uptake. Considering reasonable physiological changes in stomatal regulation, the modeled value was not larger than 1.05 cm s-1. Instead, the observed fluxes could be explained with the model by decreasing the cuticular resistance to ozone deposition from 5000 to 1000 s m-1
Eddy flux and leaf level measurements of biogeni VOC emissions from Mopane woodland of Botswana
Greenberg, J.P. ; Guenter, A. ; Harley, P. ; Otter, L. ; Veenendaal, E.M. ; Hewwit, C.N. ; James, A.E. ; Owen, S.M. - \ 2003
Journal of Geophysical Research: Atmospheres 108 (2003). - ISSN 2169-897X - p. 8466 - 8466.
quercus-ilex l - organic-compound emissions - tropical forest site - monoterpene emissions - isoprene - expresso - model - light
Biogenic volatile organic compound (BVOC) emissions were measured in a mopane woodland near Maun, Botswana in January–February 2001 as part of SAFARI 2000. This landscape is comprised of more than 95% of one woody plant species, Colophospermum mopane (Caesalpinaceae). Mopane woodlands extend over a broad area of southern Africa. A leaf cuvette technique was used to determine the emission capacities of the major vegetation and the temperature and light dependence of the emissions. In addition, relaxed eddy accumulation (REA) measurements of BVOC fluxes were made on a flux tower, where net CO2 emissions were also measured simultaneously. Large light-dependent emissions of terpenes (mostly a-pinene and d-limonene) were observed from the mopane woodland. The diurnal BVOC emissions were integrated and compared with the CO2 flux. Monoterpene flux exceeded 3000 µg C m-2 h-1 during the daytime period, comparable to isoprene fluxes and much higher than terpene fluxes measured in most areas. The terpene flux constituted approximately 25% of the diurnal net carbon exchange (CO2) during the experimental period. Other BVOC emissions may also contribute to the carbon exchange.