Iron Addition to Soil Specifically Stabilized Lignin

Date
2016-07-01
Authors
Hall, Steven
Silver, Whendee
Hall, Steven
Timokhin, Vitaliy
Hammel, Kenneth
Major Professor
Advisor
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Altmetrics
Authors
Research Projects
Organizational Units
Journal Issue
Series
Department
Ecology, Evolution and Organismal Biology
Abstract

The importance of lignin as a recalcitrant constituent of soil organic matter (SOM) remains contested. Associations with iron (Fe) oxides have been proposed to specifically protect lignin from decomposition, but impacts of Fe-lignin interactions on mineralization rates remain unclear. Oxygen (O2) fluctuations characteristic of humid tropical soils drive reductive Fe dissolution and precipitation, facilitating multiple types of Fe-lignin interactions that could variably decompose or protect lignin. We tested impacts of Fe addition on 13C methoxyl-labeled lignin mineralization in soils that were exposed to static or fluctuating O2. Iron addition suppressed lignin mineralization to 21% of controls, regardless of O2 availability. However, Fe addition had no effect on soil CO2 production, implying that Fe oxides specifically protected lignin methoxyls but not bulk SOM. Iron oxide-lignin interactions represent a specific mechanism for lignin stabilization, linking SOM biochemical composition to turnover via geochemistry.

Comments

This article is from Soil Biology and Biochemistry 98 (2016): 95, doi: 10.1016/j.soilbio.2016.04.010. Posted with permission.

Description
Keywords
Citation
DOI
Collections