The crucial role of blue light as a driver of photodegradation in terrestrial ecosystems on the global scale: a meta-analysis

Marta Pieristè, Qing-Wei Wang, Titta Kotilainen, Estelle Forey, Matthieu Chauvat, Hiroko Kurokawa, T Matthew Robson, Alan G. Jones

Research output: Contribution to journalArticleScientificpeer-review


Wherever sunlight reaches litter there is potential for photodegradation to contribute to decomposition. Typically, ultraviolet (UV) radiation has been considered the main driver of this process and has been broadly studied in many biomes. However, short-wavelength visible light was lately identified as biologically active in litter photodegradation along with UV radiation. Whilst several reviews have attempted to identify how photodegradation affects decomposition, we aimed to tease apart the extent to which different spectral regions contribute to this process globally. We performed a meta-analysis of studies that assessed photodegradation through spectrally selective attenuation of solar radiation, to identify the impact of waveband-dependent photodegradation on litter mass loss across all studied biomes under ambient sunlight. We found the full-spectrum of sunlight to increase litter mass loss by 14% across all studies. When accounting for spectral composition, blue light-driven photodegradation alone was responsible for most of this increase in mass loss (12%). This highlights the crucial role of visible light in the photodegradation process. On the other hand, any effects of UV and its constituent UV-B radiation were not significant at the global scale only at a local scale, while UV-A radiation reduced mass loss by 5% globally. These waveband-dependent effects were modulated by climate, ecosystem type and decay period. Relating photodegradation rates with initial litter traits, we did not find any of the classical litter traits to predict photodegradation on a global scale, suggesting different traits to be relevant in different biomes. However, there have been too few studies to make confident general inferences about photodegradation at high latitudes and in ecosystems characterized by high canopy cover, where further investigation is needed to better explain the role of photodegradation globally.
Original languageEnglish
Number of pages32
Publication statusUnpublished - 8 Jan 2020
MoE publication typeA1 Journal article-refereed

Bibliographical note

This is the version published as part of Marta Pietiste's PhD Dissertation

Fields of Science

  • 1181 Ecology, evolutionary biology
  • Photodegradation
  • UV
  • litter traits
  • blue light
  • decomposition

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