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Iskalni niz: "avtor" (Saša Zavadlav) .

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Trace elements and nitrogen content in naturally growing moss Hypnum cupressiforme in urban and peri-urban forests of the Municipality of Ljubljana (Slovenia)
S. Berisha, Mitja Skudnik, Urša Vilhar, M. Saboljević, Saša Zavadlav, Zvonka Jeran, 2017

Povzetek: We monitored trace metals and nitrogen using naturally growing moss Hypnum cupressiforme Hedw. in urban and peri-urban forests of the City Municipality of Ljubljana. The aim of this study was to explore the differences in atmospheric deposition of trace metals and nitrogen between urban and peri-urban forests. Samples were collected at a total of 44 sites in urban forests (forests within the motorway ring road) and peri-urban forests (forests outside the motorway ring road). Mosses collected in urban forests showed increased trace metal concentrations compared to samples collected from peri-urban forests. Higher values were significant for As, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Tl and V. Within the motorway ring road, the notable differences in element concentrations between the two urban forests were significant for Cr, Ni and Mo. Factor analysis showed three groups of elements, highlighting the contribution of traffic emissions, individual heating appliances and the resuspension of contaminated soils and dust as the main sources of trace elements in urban forests.
Ključne besede: heavy metals, biomonitoring, Ljubljana, ICP-MS, elemental analysis, factor analysis, traffic emissions
DiRROS - Objavljeno: 12.07.2017; Ogledov: 2436; Prenosov: 701
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Measuring techniques for concentration and stable isotopologues of CO2 in a terrestrial ecosystem : a review
Grega E. Voglar, Saša Zavadlav, Tom Levanič, Mitja Ferlan, 2019

Povzetek: Measurements of carbon dioxide and their stable isotopes are propulsive research tool in ecology and environmental science as they can give us insight into carbon cycle. They are widely used to investigate both natural and anthropogenic carbon sources in the atmosphere, hydrosphere and geosphere, as well as the exchange between these reservoirs. In this paper, we provide a basic overview of two different analytical measurement techniques, isotope ratio mass spectrometry (IRMS) and laser-absorption spectroscopy (LAS) which have been developed and utilized for monitoring of CO2 isotopologues in ecosystem. We present the basics for each technique, however with the emphasis on LAS measurement technique we are targeting readers who are not familiar with this topic. A major objective of this paper is to illustrate the current value and future potential of various analytical instruments in a wide range of applications deployed in the terrestrial ecosystem. Finally, we draw a conclusion from recent research campaigns by presenting a decision tree to better understand and choose a correct application combination for a selected scale of ecosystem.
Ključne besede: Isotope ratio mass spectrometry, laser-absorption spectroscopy, CO2 isotopologues, terrestrial ecosystem, decision tree, spectroscopic databases
DiRROS - Objavljeno: 18.02.2020; Ogledov: 1203; Prenosov: 409
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Isotopic and water relation responses to ozone and water stress in seedlings of three oak species with different adaptation strategies
Claudia Cocozza, Tom Levanič, Saša Zavadlav, Tanja Mrak, Elena Paoletti, Yasutomo Hoshika, Alessio Giovannelli, Hojka Kraigher, 2020

Povzetek: The impact of global changes on forest ecosystem processes is based on the species-specific responses of trees to the combined effect of multiple stressors and the capacity of each species to acclimate and cope with the environment modification. Combined environmental constraints can severely affect plant and ecological processes involved in plant functionality. This study provides novel insights into the impact of a simultaneous pairing of abiotic stresses (i.e., water and ozone (O3) stress) on the responses of oak species. Water stress (using 40 and 100% of soil water content at field capacity - WS and WW treatments, respectively) and O3 exposure (1.0, 1.2, and 1.4 times the ambient concentration - AA, 1.2AA, and 1.4AA, respectively) were carried out on Quercus robur L., Quercus ilex L., and Quercus pubescens Willd. seedlings, to study physiological traits (1. isotope signature [delta 13C, delta 18O and delta 15N], 2. water relation [leaf water potential, leaf water content], 3. leaf gas exchange [light-saturated net photosynthesis, Asat, and stomatal conductance, gs]) for adaptation strategies in a Free-Air Controlled Exposure (FACE) experiment. Ozone decreased Asat in Q. robur and Q. pubescens while water stress decreased it in all three oak species. Ozone did not affect delta 13C, whereas delta 18O was influenced by O3 especially in Q. robur. This may reflect a reduction of gs with the concomitant reduction in photosynthetic capacity. However, the effect of elevated O3 on leaf gas exchange as indicated by the combined analysis of stable isotopes was much lower than that of water stress. Water stress was detectable by delta 13C and by delta 18O in all three oak species, while delta 15N did not define plant response to stress conditions in any species. The delta 13C signal was correlated to leaf water content (LWC) in Q. robur and Q. ilex, showing isohydric and anisohydric strategy, respectively, at increasing stress intensity (low value of LWC). No interactive effect of water stress and O3 exposure on the isotopic responses was found, suggesting no cross-protection on seasonal carbon assimilation independently on the species adaptation strategy.
Ključne besede: ozone, gas exchange, English oak, holm oak, downy oak, Quercus ilex L., Quercus robur L., Quercus pubescens Willd
DiRROS - Objavljeno: 11.08.2020; Ogledov: 1104; Prenosov: 660
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