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Carbon exchange between the terrestrial biosphere and the atmosphere is one of the key processes that need to be assessed in the context of the Kyoto Protocol. Several studies suggest that the terrestrial biosphere is gaining carbon, but these estimates are obtained primarily by indirect methods, and the factors that control terrestrial carbon exchange, its(More)
Temperate and boreal forests in the Northern Hemisphere cover an area of about 2 x 10(7) square kilometres and act as a substantial carbon sink (0.6-0.7 petagrams of carbon per year). Although forest expansion following agricultural abandonment is certainly responsible for an important fraction of this carbon sink activity, the additional effects on the(More)
Concentrations of nitrogen gases (NH(3), NO(2), NO, HONO and HNO(3)) and particles (pNH(4) and pNO(3)) were measured over a mixed coniferous forest impacted by high nitrogen loads. Nitrogen dioxide (NO(2)) represented the main nitrogen form, followed by nitric oxide (NO) and ammonia (NH(3)). A combination of gradient method (NH(3) and NO(x)) and resistance(More)
An intercomparison study of two methods for estimating forest soil CO2 efflux was conducted during a 3-week period in summer. An empirical model established from nearly 2 years of chamber measurements predicted that the soil CO2 efflux ranged from 1.2 to 1.4 mmol m−2 s−1. This small range was due to the lack of variability in the model parameters (soil(More)
Hexaploid bread wheat evolved from a rare hybridisation, which resulted in a loss of genetic diversity in the wheat D-genome with respect to the ancestral donor, Aegilops tauschii. Novel genetic variation can be introduced into modern wheat by recreating the above hybridisation; however, the information associated with the Ae. tauschii accessions in(More)
The relationship between the oleophobicity of micropatterned surfaces and the reduction of oil adhesion at low temperatures was explored by using siloxane elastomer surfaces as a model system. Polydimethylsiloxane (PDMS) surfaces were fabricated with varying oleophobicity from oleophilic to superoleophobic by combing the blending of(More)
The accurate assessment of respiration by woody vegetation, still a challenge in plant productivity models, is generally a problem of correctly scaling-up the process from organs to the whole plant. We used a large (41.6 m3), canopy chamber to enclose mature olive trees and to measure aboveground respiration (R ag ) under natural environmental conditions in(More)
Biogeosciences Discussions This discussion paper is/has been under review for the journal Biogeosciences (BG). Please refer to the corresponding final paper in BG if available. Abstract Two years of continuous measurements of net ecosystem exchange (NEE) using the eddy covariance technique were made over a Mediterranean alpine shrubland. These ecosystems(More)
To study the effects of warming and declining species richness on the carbon balance of grassland communities, model ecosystems containing one, three or nine species were exposed to ambient and elevated (ambient +3 • C) air temperature. In this paper, we analyze measured ecosystem CO 2 fluxes to test whether ecosystem photosynthesis 5 and respiration had(More)
Date The final copy of this thesis has been examined by the signatories, and we Find that both the content and the form meet acceptable presentation standards Of scholarly work in the above mentioned discipline. Quantitative modeling of the reaction/diffusion kinetics of two-chemistry photopolymers Thesis directed by Associate Professor Robert R. McLeod(More)