Workpackage Spatial heterogeneity of ecosystem carbon fluxes


Workpackage manager: Prof. Dr. Ing.Michal V. MAREK & Prof. Dr. Zoltán TUBA


Objectives:
Aim of WP 7 is to quantify the spatial heterogeneity of ecosystem carbon fluxes using a combination of fluorescence, chamber and eddy covariance measurements, and footprint modelling.

Methodology / work description:
Concurrently to measurements of NEE by means of eddy covariance (cf. WP 1), the heterogeneity of NEE will be assessed using chambers and a novel fluorescence imaging technique based on a CCD camera. The CCD camera fluorometer will be placed above selected vegetation parts within the source area of the eddy covariance system. The system of actinic LEDs provides the basis for the induction and sensing of the fluorescence signal. The CCD camera allows to obtain a continuous spatially distributed fluorescence signal. Because the fluorescence is proportional to the assimilatory activity, the spatial picture of the fluorescence signal can be used as a tracer for the amount, distribution and time-duration of canopy photosynthesis. The small-scale variability in NEE, from the level of organs up to larger patches of vegetation, will be studied using a series of differently-sized chambers and respective fluorescence images. The spatial heterogeneity of NEE at the scale of the source area of the eddy covariance system will be determined using footprint modelling, in conjunction with detailed vegetation maps and stand-scale fluorescence images, and the NEE measurements made by eddy covariance. The results of the combined small-scale chamber and fluorescence measurements will then be used to calibrate the results of the footprint analysis.


Deliverables:

  • Development and adaptation of a CCD camera fluorometer for sensing the spatial distribution of assimilatory activity of grassland vegetation
  • Seasonal course of the spatial distribution of the assimilatory activity of the vegetation
  • Analysis of the spatial heterogeneity of carbon fluxes at the scales of patch, ecosystem and landscape

Milestones:

  • Fluorescence imaging system adapted and tested
  • Seasonal course of the spatial distribution of the assimilatory activity of the vegetation available
  • Analysis of the spatial heterogeneity of ecosystem carbon fluxes