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.
COBISS.SI-ID: 5538470
Patterns of drought severity in natural ecosystems depend on ecosite characteristics, particularly on local soil water availability and microclimate (evaporative demand). At the sites with less favourable conditions, the plasticity of fundamental drought adaptive traits can be exceeded under severe drought, even in well adapted species. In our study, anatomical and physiological adjustments to drought were studied in pubescent oak (Quercus pubescens Willd.) growing on adjacent sub-Mediterranean plots (ecosites) differing in bedrock and soil type (limestone with rendzic leptosol, low water retention - L; transition from limestone to flysch with eutric cambisol, high water retention - F). In both years of the study, 2015 and 2016, in the part of the season with sufficient water supply, sap flow density (SFD) was higher in oaks growing on L than those growing on F. With decreasing soil water content (SWC) in July, SFD was reduced on both plots, most in trees growing on limestone. In the period of severe drought, SFD in trees growing on L was decoupled from the changes of VPD, due to increased employment of water conservation strategies, such as decreases in stomatal conductance. This was further translated into stomatal limitation of photosynthesis and contributed to reduced radial stem growth. The seasonal dynamics of traits indicate that Q. pubescens trees use a predisposed anatomical strategy (average size of vessels in different years), adjusted to average ecosite conditions.
COBISS.SI-ID: 9243513