The role of DOM sorption to mineral surfaces in the preservation of organic matter in soils
The role of DOM sorption to mineral surfaces in the preservation of organic matter in soils
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DOI：
10.1016/s0146-6380(00)00046-2
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发表时间：
2000-01-01
影响因子：
3
通讯作者：
Guggenberger, G
中科院分区：
文献类型：
--
作者：
Kaiser, K;Guggenberger, G
溶解有机质（DOM）的吸附作用是海洋沉积物中有机质保存的主要过程。这一假设的证据包括沉积物表面积（SA）和有机碳（OC）浓度和DOM吸附到矿物表面后的生物降解性大大降低之间的密切关系。本研究的目的是讨论在土壤环境中类似过程的可能性。我们完成了这一点，从文献中收集信息，并通过我们自己的研究DOM的吸附和积累的OM在土壤中的评价。我们发现，在土壤中的有机质与矿物基质存在密切的关联。土壤有机质的浓度与矿物基质，DOM的吸附有关的反应性矿物相，如铝和铁的羟基氧化物。木质纤维素的氧化分解产生的DOM吸附铝和铁的羟基氧化物涉及表面金属和酸性有机配体之间的强络合键，特别是与芳香族结构相关的那些。吸附强度与表面积有关，但更重要的是与吸附矿物相的表面性质有关。大部分DOM的吸附在类似于吸附过程中的条件下几乎不可逆（滞后）。由于吸附的更不稳定的多糖衍生的DOM矿物表面上是较弱的，吸附和解吸过程强烈地有利于积累的更难消化的木质素衍生的DOM。此外，我们发现土壤OM在冲积层B层和表土的粘土部分强烈类似木质素衍生的DOM从上覆的森林地板。因此，DOM的吸附对土壤有机质的积累和保存有重要作用。然而，这并不导致OC浓度和SA之间的显着关系。这一发现的原因可能是“掩蔽”的矿物表面吸附OM，在高活性位点的金属氢氧化物的OM补丁的集群，和/或SA和表面活性的Fe和Al羟基氧化物的浓度在某些土壤类型之间的关系的情况下。总体而言，我们得出结论，吸附保存OM在土壤中的吸附DOM的化学结构和矿物基质的表面性质的影响。吸附OM的定位和构象仍不清楚，因此应进一步研究的主题。(C)2000爱思唯尔科技有限公司版权所有。
Sorption of dissolved organic matter (DOM) is considered to be a major process in the preservation of organic matter (OM) in marine sediments. Evidence for this hypothesis includes the close relationship between sediment surface area (SA) and organic carbon (OC) concentrations and the strongly reduced biological degradability after DOM has sorbed to mineral surfaces. The aim of this study was to discuss the possibility of a similar process in the soil environment. We accomplished this by gathering information from the literature, and by an evaluation of our own studies on DOM sorption and accumulation of OM in soil. We found that in soil a close association of OM with the mineral matrix exists. Both the concentration of soil OM associated with the mineral matrix, and the sorption of DOM are related to reactive mineral phases such as Al and Fe oxyhydroxides. Sorption of DOM derived from the oxidative decomposition of lignocellulose to Al and Fe oxyhydroxides involves strong complexation bondings between surface metals and acidic organic ligands, particularly with those associated with aromatic structures. The strength of the sorption relates to the surface area but more importantly to the surface properties of the sorbing mineral phase. The sorption of a large part of DOM is hardly reversible under conditions similar to those during sorption (hysteresis). Because sorption of the more labile polysaccharide-derived DOM on mineral surfaces is weaker, adsorptive and desorptive processes strongly favour the accumulation of the more recalcitrant lignin-derived DOM. In addition, we found the soil OM in an alluvial B horizon and in the clay fraction of a topsoil strongly resembling lignin-derived DOM from the overlying forest floors. Hence, it seems likely that sorption of DOM contributes considerably to the accumulation and preservation of OM in soil. However, this does not result in a significant relationship between OC concentration and SA. Reasons for that finding may be the "masking" of mineral surfaces by adsorbed OM, the clustering of OM patches at highly reactive sites of metal hydroxides, and/or the absence of a relationship between SA and the concentration of surface-active Fe and Al oxyhydroxides in some soil types. Overall, we conclude that sorptive preservation of OM in soil is affected by the chemical structure of the sorbing DOM and the surface properties of the mineral matrix. Localisation and conformation of sorbed OM remains unclear and therefore should be subject of further research. (C) 2000 Elsevier Science Ltd. All rights reserved.