Diatoms can represent the major component of phytoplankton and contribute massively to global primary production in the oceans. Over tens of millions of years they developed an intricate porous silica shell, the frustule, which ensures mechanical protection, sorting of nutrients from harmful agents, and optimization of light harvesting. Several groups of microalgae evolved different strategies of protection towards ultraviolet radiation (UVR), which is harmful for all living organisms mainly through the formation of dimeric photoproducts between adjacent pyrimidines in DNA. Even in presence of low concentrations of UV-absorbing compounds, several diatoms exhibit significant UVR tolerance. We here investigated the mechanisms involved in UVR screening by diatom silica investments focusing on single frustules of a planktonic centric diatom, Coscinodiscus wailesii, analyzing absorption by the silica matrix, diffraction by frustule ultrastructure and also UV conversion into photosynthetically active radiation exerted by nanostructured silica photoluminescence. We identified the defects and organic residuals incorporated in frustule silica matrix which mainly contribute to absorption; simulated and measured the spatial distribution of UVR transmitted by a single valve, finding that it is confined far away from the diatom valve itself; furthermore, we showed how UV-to-blue radiation conversion (which is particularly significant for photosynthetic productivity) is more efficient than other emission transitions in the visible spectral range.

De Tommasi, E., Congestri, R., Dardano, P., De Luca, A.c., Managò, S., Rea, I., et al. (2018). UV-shielding and wavelength conversion by centric diatom nanopatterned frustules. SCIENTIFIC REPORTS, 8(1) [10.1038/s41598-018-34651-w].

UV-shielding and wavelength conversion by centric diatom nanopatterned frustules

Congestri, Roberta;
2018

Abstract

Diatoms can represent the major component of phytoplankton and contribute massively to global primary production in the oceans. Over tens of millions of years they developed an intricate porous silica shell, the frustule, which ensures mechanical protection, sorting of nutrients from harmful agents, and optimization of light harvesting. Several groups of microalgae evolved different strategies of protection towards ultraviolet radiation (UVR), which is harmful for all living organisms mainly through the formation of dimeric photoproducts between adjacent pyrimidines in DNA. Even in presence of low concentrations of UV-absorbing compounds, several diatoms exhibit significant UVR tolerance. We here investigated the mechanisms involved in UVR screening by diatom silica investments focusing on single frustules of a planktonic centric diatom, Coscinodiscus wailesii, analyzing absorption by the silica matrix, diffraction by frustule ultrastructure and also UV conversion into photosynthetically active radiation exerted by nanostructured silica photoluminescence. We identified the defects and organic residuals incorporated in frustule silica matrix which mainly contribute to absorption; simulated and measured the spatial distribution of UVR transmitted by a single valve, finding that it is confined far away from the diatom valve itself; furthermore, we showed how UV-to-blue radiation conversion (which is particularly significant for photosynthetic productivity) is more efficient than other emission transitions in the visible spectral range.
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore BIO/01
English
www.nature.com/srep/index.html
De Tommasi, E., Congestri, R., Dardano, P., De Luca, A.c., Managò, S., Rea, I., et al. (2018). UV-shielding and wavelength conversion by centric diatom nanopatterned frustules. SCIENTIFIC REPORTS, 8(1) [10.1038/s41598-018-34651-w].
De Tommasi, E; Congestri, R; Dardano, P; De Luca, Ac; Managò, S; Rea, I; De Stefano, M
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/213113
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