Accelerated mineral bio-carbonation of coarse residue kimberlite material by inoculation with photosynthetic microbial mats

Geochemical Transactions

Research

Jordan Poitras¹  Emma Gagen¹  Thomas Ray Jones¹  Gordon Southam¹  David John Paterson² 

[1] School of Earth & Environmental Sciences, The University of Queensland, 4072, St. Lucia, QLD, Australia;The Australian Synchrotron (ANSTO), 3168, Clayton, VIC, Australia;

关键词: Kimberlite;    Mineral carbonation;    Photosynthetic biofilm;   

DOI  :  10.1186/s12932-023-00082-4

 received in 2022-11-23, accepted in 2023-05-23,  发布年份 2023

来源: Springer

【 摘 要 】

Microbiological weathering of coarse residue deposit (CRD) kimberlite produced by the Venetia Diamond Mine, Limpopo, South Africa enhanced mineral carbonation relative to untreated material. Cultures of photosynthetically enriched biofilm produced maximal carbonation conditions when mixed with kimberlite and incubated under near surface conditions. Interestingly, mineral carbonation also occurred in the dark, under water-saturated conditions. The examination of mineralized biofilms in ca. 150 µm-thick-sections using light microscopy, X-ray fluorescence microscopy (XFM) and backscatter electron—scanning electron microscopy-energy dispersive x-ray spectrometry demonstrated that microbiological weathering aided in producing secondary calcium/magnesium carbonates on silicate grain boundaries. Calcium/magnesium sulphate(s) precipitated under vadose conditions demonstrating that evaporites formed upon drying. In this system, mineral carbonation was only observed in regions possessing bacteria, preserved within carbonate as cemented microcolonies. 16S rDNA molecular diversity of bacteria in kimberlite and in natural biofilms growing on kimberlite were dominated by Proteobacteria that are active in nitrogen, phosphorus and sulphur cycling. Cyanobacteria based enrichment cultures provided with nitrogen & phosphorus (nutrients) to enhance growth, possessed increased diversity of bacteria, with Proteobacteria re-establishing themselves as the dominant bacterial lineage when incubated under dark, vadose conditions consistent with natural kimberlite. Overall, 16S rDNA analyses revealed that weathered kimberlite hosts a diverse microbiome consistent with soils, metal cycling and hydrocarbon degradation. Enhanced weathering and carbonate-cemented microcolonies demonstrate that microorganisms are key to mineral carbonation of kimberlite.

【 授权许可】

CC BY   
© The Author(s) 2023

【 图 表 】

Fig. 3

Fig. 5

Fig. 2

Fig. 6

13690_2023_1130_Article_IEq47.gif

13690_2023_1130_Article_IEq34.gif

13690_2023_1130_Article_IEq27.gif

40517_2023_252_Article_IEq151.gif

13690_2023_1130_Article_IEq10.gif

Fig. 2