Simple plant and microbial exudates destabilize mineral-Associated organic matter via multiple pathways
Li, Hui ; Bolscher, Tobias LU
; Winnick, Matthew
; Tfaily, Malak M.
; Cardon, Zoe G.
and Keiluweit, Marco
(2021)
In Environmental Science and Technology
55(5).
p.3389-3398
- Abstract
Most mineral-Associated organic matter (MAOM) is protected against microbial attack, thereby contributing to longterm carbon storage in soils. However, the extent to which reactive compounds released by plants and microbes may destabilize MAOM and so enhance microbial access, as well as the underlying mechanisms, remain unclear. Here, we tested the ability of functionally distinct model exudates-ligands, reductants, and simple sugars-To promote microbial utilization of monomeric MAOM, bound via outer-sphere complexes to common iron and aluminum (hydr)oxide minerals. The strong ligand oxalic acid induced rapid MAOM mineralization, coinciding with greater sorption to and dissolution of minerals, suggestive of direct MAOM mobilization... (More)
Most mineral-Associated organic matter (MAOM) is protected against microbial attack, thereby contributing to longterm carbon storage in soils. However, the extent to which reactive compounds released by plants and microbes may destabilize MAOM and so enhance microbial access, as well as the underlying mechanisms, remain unclear. Here, we tested the ability of functionally distinct model exudates-ligands, reductants, and simple sugars-To promote microbial utilization of monomeric MAOM, bound via outer-sphere complexes to common iron and aluminum (hydr)oxide minerals. The strong ligand oxalic acid induced rapid MAOM mineralization, coinciding with greater sorption to and dissolution of minerals, suggestive of direct MAOM mobilization mechanisms. In contrast, the simple sugar glucose caused slower MAOM mineralization, but stimulated microbial activity and metabolite production, indicating an indirect microbially-mediated mechanism. Catechol, acting as reductant, promoted both mechanisms. While MAOM on ferrihydrite showed the greatest vulnerability to both direct and indirect mechanisms, MAOM on other (hydr)oxides was more susceptible to direct mechanisms. These findings suggest that MAOM persistence, and thus longterm carbon storage within a given soil, is not just a function of mineral reactivity but also depends on the capacity of plant roots and associated microbes to produce reactive compounds capable of triggering specific destabilization mechanisms.
(Less)
- author
- Li, Hui
; Bolscher, Tobias
LU
; Winnick, Matthew
; Tfaily, Malak M.
; Cardon, Zoe G.
and Keiluweit, Marco
- organization
- publishing date
- 2021-03
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Environmental Science and Technology
- volume
- 55
- issue
- 5
- pages
- 10 pages
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- pmid:33587629
- scopus:85101534943
- ISSN
- 0013-936X
- DOI
- 10.1021/acs.est.0c04592
- language
- English
- LU publication?
- yes
- id
- 87bad0cb-45ae-4ec4-9aae-b80bd7cf0fee
- date added to LUP
- 2021-12-27 14:18:22
- date last changed
- 2024-04-20 19:24:53
@article{87bad0cb-45ae-4ec4-9aae-b80bd7cf0fee,
abstract = {{<p>Most mineral-Associated organic matter (MAOM) is protected against microbial attack, thereby contributing to longterm carbon storage in soils. However, the extent to which reactive compounds released by plants and microbes may destabilize MAOM and so enhance microbial access, as well as the underlying mechanisms, remain unclear. Here, we tested the ability of functionally distinct model exudates-ligands, reductants, and simple sugars-To promote microbial utilization of monomeric MAOM, bound via outer-sphere complexes to common iron and aluminum (hydr)oxide minerals. The strong ligand oxalic acid induced rapid MAOM mineralization, coinciding with greater sorption to and dissolution of minerals, suggestive of direct MAOM mobilization mechanisms. In contrast, the simple sugar glucose caused slower MAOM mineralization, but stimulated microbial activity and metabolite production, indicating an indirect microbially-mediated mechanism. Catechol, acting as reductant, promoted both mechanisms. While MAOM on ferrihydrite showed the greatest vulnerability to both direct and indirect mechanisms, MAOM on other (hydr)oxides was more susceptible to direct mechanisms. These findings suggest that MAOM persistence, and thus longterm carbon storage within a given soil, is not just a function of mineral reactivity but also depends on the capacity of plant roots and associated microbes to produce reactive compounds capable of triggering specific destabilization mechanisms.</p>}},
author = {{Li, Hui and Bolscher, Tobias and Winnick, Matthew and Tfaily, Malak M. and Cardon, Zoe G. and Keiluweit, Marco}},
issn = {{0013-936X}},
language = {{eng}},
number = {{5}},
pages = {{3389--3398}},
publisher = {{The American Chemical Society (ACS)}},
series = {{Environmental Science and Technology}},
title = {{Simple plant and microbial exudates destabilize mineral-Associated organic matter via multiple pathways}},
url = {{http://dx.doi.org/10.1021/acs.est.0c04592}},
doi = {{10.1021/acs.est.0c04592}},
volume = {{55}},
year = {{2021}},
}