Ammoniakudveksling over Lille Bøgeskov: Ammonia exchanges above Lille Bøgeskov

Christian D. H. Arentsen, Karen A. Gammeltoft, Liv B. Lillevang, Mie L. Jeppesen, Mirte Te Brake, Morten Egedal & Sasha Al-Awkati

Studenteropgave: Semesterprojekt

Abstrakt

With the working title “Ammonia exchanges above Lille Bøgeskov”, this study examines the exchanges of ammonia gases between the atmosphere and canopy above a beech forest. In particular, the study examines the relation between surface-atmosphere gas exchanges and the development of the canopy during defoliation. Measured in the study are four parameters reflecting the development of the condition of the canopy, respectively the stomatal resistance, Leaf Area Index (LAI), the leaf nitrogen concentration on canopy scale, which are all measured manually, and canopy CO2-fluxes measured above the forest. Each of the four parameters reflects in different ways the activity level of the canopy, which are descending during the measuring period. This study aims to support newer research which shows, that forests, as previously thought, do not only function as sink for ammonia gases but in specific periods also function as a source. The study is based on measurements that were taken from the forest called Lille Bøgeskov, (translated to Small Beech Forest) near Sorø in Denmark at fall 2012. The manual measurements were collected approximately once a week during the period 2nd – 23rd of October. The data were measured by Ph.d–student Kristina Hansen, while CO2-fluxes and meteorological data were measured by Risø research center. Results of the measurements are showing tendencies in agreement with newer research that the forest during defoliation also will work as source with ammonia emission to the atmosphere. But due to a short measurement period and missing data of the ammonia fluxes for the specific measurement period, the study is not able to conclude whether one or more of the parameters measured in the study in greater magnitude are related to the ammonia fluxes. Though the study found that temperature has a dominating influence on the ammonia-fluxes, which the study connects with the canopy having an ammonia compensationpoint, that causes the canopy to act as either sink or source.

UddannelserBasis - Naturvidenskabelig Bacheloruddannelse, (Bachelor uddannelse) Basis
SprogDansk
Udgivelsesdato16 jan. 2013

Emneord

  • Ammoniak
  • Lille Bøgeskov
  • Gasudvekslinger