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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Photodegradation influences litter decomposition rate in a humid tropical ecosystem, Brazil

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Marinho, Osmarina A. [1] ; Martinelli, Luiz A. [1] ; Duarte-Neto, Paulo J. [2] ; Mazzi, Edmar A. [1] ; King, Jennifer Y. [3]
Total Authors: 5
[1] Univ Sao Paulo, Ctr Nucl Energy Agr, BR-13400970 Piracicaba, SP - Brazil
[2] Univ Fed Rural Pernambuco, Dept Stat & Informat, BR-52171900 Recife, PE - Brazil
[3] Univ Calif Santa Barbara, Dept Geog, Santa Barbara, CA 93106 - USA
Total Affiliations: 3
Document type: Journal article
Source: Science of The Total Environment; v. 715, MAY 1 2020.
Web of Science Citations: 0

Solar radiation in general and UV radiation in particular have been recognized to stimulate plant litter decomposition through photochemical mineralization of organic molecules such as lignin and through facilitation of microbial decomposition in dryland ecosystems. However, little is known about how photodegradation may influence decomposition in other ecosystems not subject to moisture limitations and under what conditions photodegradation may be favored. Decomposition in humid tropical ecosystems is a complex process, and it can be influenced by a number of environmental factors that are distinct from arid and semi-arid ecosystems. To assess the mechanisms underlying photodegradation by ultraviolet B (UV-B) radiation in a humid tropical ecosystem, we designed a 300-day field experiment in a tropical site in Brazil with high levels of annual precipitation, compared to arid ecosystems, and exposed litter to three levels of radiation (full sun, UV-B removed, and shade) combined with a biocide treatment. Results show that after nearly one year of exposure, the microbial biomass was not affected by UV-B incidence, and this effect has not yet been fully understood for tropical ecosystems. Modeled using an exponential deceleration equation, the removal of UV-B radiation decelerated the plant litter decomposition rate for the control conditions by 21% compared to litter exposed to full sun. Interestingly, shaded litter exhibited similar mass loss compared to litter exposed to full sun. Furthermore, differences in the decay constant among radiation treatments due to the UV-B effect were independent of lignin loss. Overall, our study suggests that UV-B radiation contributed to plant litter decomposition through carbon losses but had no discernible effect on nitrogen, lignin, or cellulose loss specifically. Importantly, our results demonstrate that photodegradation occurs under humid tropical conditions, and further studies are necessary to examine the mechanisms of carbon loss. (C) 2020 Published by Elsevier B.V. (AU)

FAPESP's process: 16/09698-9 - Effects of UV-B radiation on litter decomposition in a Tropical Ecosystem - Determination of constant (k) of decomposition and litter quality
Grantee:Osmarina Alves Marinho
Support type: Scholarships abroad - Research Internship - Master's degree
FAPESP's process: 15/00971-1 - Plant litter decomposition under the effect of photodegradation in an Brazilian atlantic montane forest ecosystem on the North Coast of São Paulo
Grantee:Osmarina Alves Marinho
Support type: Scholarships in Brazil - Master