Earthworms are considered as “ecosystem engineers” impacting soil properties as well as nutrient and element cycles. As they move through soil, earthworms secrete cutaneous mucus which is metabolized by soil microorganisms and a source of plant-available nutrients. Earthworm-processed soil contains carbon enriched, earthworm-specific soil aggregates (e.g. casts and middens) in comparison to earthworm unaffected soil. The reason could be that organic polymeric substances in earthworm mucus bind to soil minerals. The objective of this study was to investigate the small-scale interactions between earthworm mucus and secondary soil minerals, e.g. goethite and illite, leading to the formation of organo-mineral associations. We characterized the chemical composition of earthworm mucus by FTIR and ¹³C-NMR spectroscopy and compared spectra of mucus to microbial extracellular polymeric substances (EPS), an abundant and well-known type of organic matter that binds with soil minerals. Mucus from anecic (Lumbricus terrestris L.) and endogeic (Aporrectodea caliginosa Sav.) earthworm species was dominated by proteins and carbohydrates. Between 21 and 36% of the total organic carbon in the mucus containing treatments adsorbed to illite and goethite, and most of the binding with goethite was associated with phosphorus containing mucus compounds. The surface charge of newly-formed organo-mineral associations was determined by measuring the isoelectric point (IEP). The IEP of mucus-goethite associations was 6.8, which was lower than the bare goethite IEP of 8.4. The zeta potential of mucus-illite associations was greater than bare illite. We conclude that the specific adsorption of earthworm mucus constituents to soil minerals leads to the formation of mucus-mineral associations. These associations contribute to retention of organic substances from earthworm mucus in soil (micro-)aggregates and explain the altered physicochemical properties of earthworm-formed aggregates in comparison to the earthworm unaffected “bulk” soil material.

are被认为是影响土壤特性以及养分和元素循环的“生态系统工程师”。当they在土壤中移动时，它们会分泌皮肤粘液，这些粘液会被土壤微生物和植物可利用的养分来源代谢。与earth未受影响的土壤相比，worm处理过的土壤含有富含碳的，特有的土壤聚集体（例如草皮和中部）。原因可能是worm粘液中的有机聚合物与土壤矿物质结合。这项研究的目的是研究earth粘液与次生土壤矿物（如针铁矿和伊利石）之间的小规模相互作用，从而导致有机-矿物缔合的形成。我们通过FTIR和¹³表征了mu的化学成分进行C-NMR光谱分析，并将黏液光谱与微生物细胞外聚合物（EPS）进行比较，EPS是一种与土壤矿物质结合的丰富而知名的有机物。粘液anecic（蚯蚓L.）和endogeic（Aporrectodea caliginosaSav。）earth物种主要由蛋白质和碳水化合物组成。含粘液的处理液中，有机碳总量的21％至36％吸附到伊利石和针铁矿上，并且大多数与针铁矿的结合与含磷的粘液化​​合物有关。通过测量等电点（IEP）来确定新形成的有机-矿物缔合的表面电荷。粘液-针铁矿协会的IEP为6.8，低于裸针铁矿IEP的8.4。粘液-伊利石结合的ζ电势大于裸伊利石。我们得出结论，worm粘液成分对土壤矿物质的特异性吸附会导致粘液-矿物质的结合。