Andrew S. Kowalski

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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)
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)
Gas exchange measurements on individual plants depend largely on chamber systems, and uncertainties and corrections in current flux calculation procedures require further assessment. We present a practical study with novel methods for analyses of flux uncertainties in an original chamber design excluding soil fluxes and allowing simultaneous measurements of(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)
Tetraploids of daylily have taken a leading position among the daylily cultivars due to desirable traits such as vigorous growth and flowers with more intense colour. In our previous studies, several tetraploids of daylily cultivars ‘Blink of an Eye’ and ‘Berlin Multi’ were obtained using in vitro techniques with different antimitotic agents (colchicine,(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)
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