Life in the dark: far-red absorbing cyanobacteria extend photic zones deep into terrestrial caves

Lars Behrendt*, Erik L. Trampe, Nadia B. Nord, Jen Nguyen, Michael Kühl, Danijela Lonco, Alex Nyarko, Ali Dhinojwala, Olivia S. Hershey, Hazel Barton

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

37 Citations (Scopus)

Abstract

Chlorophyll (Chl) f and d are the most recently discovered chlorophylls, enabling cyanobacteria to harvest near-infrared radiation (NIR) at 700–780 nm for oxygenic photosynthesis. Little is known about the occurrence of these pigments in terrestrial habitats. Here, we provide first details on spectral photon irradiance within the photic zones of four terrestrial cave systems in concert with a detailed investigation of photopigmentation, light reflectance and microbial community composition. We frequently found Chl f and d along the photic zones of caves characterized by low light enriched in NIR and inhabited by cyanobacteria producing NIR-absorbing pigments. Surprisingly, deeper parts of caves still contained NIR, an effect likely attributable to the reflectance of specific wavelengths by the surface materials of cave walls. We argue that the stratification of microbial communities across the photic zones of cave entrances resembles the light-driven species distributions in forests and aquatic environments.

Original languageEnglish
JournalEnvironmental Microbiology
Volume22
Issue number3
Pages (from-to)952-963
ISSN1462-2912
DOIs
Publication statusPublished - 2020

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