Cyanobacterial mineralisation of posnjakite (Cu4(SO4)(OH)6·H2O) in Cu-rich acid mine drainage at Yanqul, northern Oman

Bernhard Pracejus*, Aliya Al-Ansari, Huda Al-Battashi

*المؤلف المقابل لهذا العمل

نتاج البحث: المساهمة في مجلةArticleمراجعة النظراء

7 اقتباسات (Scopus)

ملخص

This is the first detailed account of the copper sulfate posnjakite (Cu4(SO4)(OH)6·H2O) coating cm-long filaments of a microbial consortium of four cyanobacteria and Herminiimonas arsenicoxydans. It was first observed on immersed plant leaves and stalks in a quarry sump of the abandoned Yanqul gold mine in the northern region of Oman; rock surfaces in the immediate vicinity show no immediate evidence of posnjakite. However, a thin unstructured layer without filaments but also containing the brightly coloured turquoise posnjakite covers ferruginous muds in the sump. Although copper is a potent bactericide, the microbes seem to survive even at the extreme heavy metal concentrations that commonly develop in the sump during the dry season (Cu2+ ≈ 2300 ppm; Zn2+ = 750 ppm; Fe2+ ≈ 120 ppm; Ni2+ = 37 ppm; Crtotal = 2.5 ppm; Cl = 8250 ppm; and SO42− = 12,250 ppm; pH ∼2.6), thus leading to the precipitation of posnjakite over a large range of physicochemical conditions. Upon exposure to the prevailing arid climate, dehydration and carbonation quickly replace posnjakite with brochantite (Cu4(SO4)(OH)6) and malachite (Cu2(CO3)(OH)2). To characterise and understand the geochemical conditions in which posnjakite precipitates from undersaturated fluids (according to our thermodynamic modelling of the dominant elements), waters from rainy and dry periods were analysed together with various precipitates and compared with the observed field occurrences. The findings imply that posnjakite should not form in the examined environment through purely inorganic mechanisms and its origin must, therefore, be linked to the encountered microbial activities.

اللغة الأصليةEnglish
الصفحات (من إلى)535-544
عدد الصفحات10
دوريةChemie der Erde
مستوى الصوت77
رقم الإصدار3
المعرِّفات الرقمية للأشياء
حالة النشرPublished - سبتمبر 2017

ASJC Scopus subject areas

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