A research group at the University of Nottingham is using a prototype fibre optic quantum sensor built by Skye Instruments to measure light profiles in mats of the lichen Cladonia. These ground-dwelling lichens dominate large areas of terrain in the Subarctic, and some temperate heathlands, often to spectacular effect.
The Nottingham group is working to identify adaptations in this peculiarly ecologically successful group of lichens that enable them to compete with and exclude vascular plants to produce extensive lichen ground cover. One factor that might be important is the capacity for lichen mats to cast deep shade and suppress seed germination and plant growth.
To test this it was necessary to measure light profiles within lichen mats in the field. However, the Cladonia species of interest produce dense multi-branched thalli that are impossible to penetrate with a conventional quantum sensor. The fibre optic system developed by Skye is 2 mm in diameter and can be pushed upwards through a wet mat to the surface, cleaned and then drawn downwards to the desired depth increments.
The system built for the Nottingham group has two sensors so that one can be positioned above the mat in an unobstructed location and the other used to record light within the lichen mat. The meter is programmed to display the ratio between the two readings and hence take account of temporal variation in solar irradiance (i.e. to display “site factors”).
We would like to thank Dr. Peter Crittenden, University of Nottingham for supplying us this story and pictures.