Incubation columns applied for simulating of microbially catalyzed mineral neoformation and early diagenesis of AMD-affected sediments

Abstract

Mining pit lakes, affected by acid mine drainage, are excellent model systems for the study of biogeochemical dynamics at acid pH. In this research natural water and sediment from monimolimnion from Filón Centro pit lake (Tharsis, Huelva) and Brunita pit lake (La Unión, Murcia) were used to build Winogradsky-type incubation columns, which allowed in-lab accelerated simulations of natural system response to biogeochemical conditions variations. In both cases, the addi- tion of organic carbon (glycerol) had strongly enhanced the growth of acidophilic microorganisms and provoked substantial neutralization process. This proves the key importance of carbon cycle in such environments. Not to mention, the presence of carbonates in the original Brunita sediment and low water-sediment relation were other abiotic factors which catalyzed the neutralization. Furthermore, abundant ferric hydroxysulfates (fundamentally, schwertmannite and jarosite) and metal (Zn, Fe, Cu) sulfides neoformation were described.