Nucleation of Fe-rich phosphates and carbonates on microbial cells and exopolymeric substances

Abstract

Although phosphate and carbonate are important constituents in ancient and modern environments, it is not yet clear their biogeochemical relationships and their mechanisms of formation. Microbially mediated carbonate formation has been widely studied whereas little is known about the formation of phosphate minerals. Here we report that a new bacterial strain, Tessarococcus lapidicaptus, isolated from the subsurface of Rio Tinto basin (Huelva, SW Spain), is capable of precipitating Fe-rich phosphate and carbonate minerals. We observed morphological differences between phosphate and carbonate, which may help us to recognize these minerals in terrestrial and extraterrestrial environments. Finally, considering the scarcity and the unequal distribution and preservation patterns of phosphate and carbonates, respectively, in the geological record and the biomineralization process that produces those minerals, we propose a hypothesis for the lack of Fe-phosphates in natural environments and ancient rocks.

Formation of Carbonate Nanoglobules by a Mixed Natural Culture under Hypersaline Conditions

“…Consistent with our results, formations of nanoglobules and nanoparticles have been reported for Ca and/or Mg carbonates [14,21,22] and for Fe carbonates and phosphates in culture experiments with different pure strains [33,34]. Demonstrating of formation of nanoglobules by a mix natural heterotrophic population together with the previous studies indicate that formation of nanoglobules and nanoparticles may not be specific to a microbial strain or activity of a particular microbial group as suggested earlier by Sanchez et al [34].…”

“…Demonstrating of formation of nanoglobules by a mix natural heterotrophic population together with the previous studies indicate that formation of nanoglobules and nanoparticles may not be specific to a microbial strain or activity of a particular microbial group as suggested earlier by Sanchez et al [34]. Particularly, lack of precipitation in the control experiments (abiotic and with dead bacterial cells) confirm that active metabolism of halophilic bacteria is essential to induce formation of various carbonate minerals.…”

“…In addition, they create appropriate microenvironments around the cell surface and provide nucleation site for adsorption of ions and initial formation of nanoglobules as it has been observed for the other microorganisms [14,[20][21][22]33,37]. Several biologic macromolecules such as phospholipids and proteins as well as EPS have been reported as a potential nucleation site for adsorption of Ca +2 [33,34,37,46,47]. Observation of nanoglobules particularly rich in P or in close spatial association to cell surface and EPS indicate the role of an organic matrix rich in phosphate group for the initial nucleation of carbonate and phosphate rich nanoglobules.…”

Vivianite formation in ferruginous sediments from Lake Towuti, Indonesia

“…Its supply to primary producers in the euphotic zone depends on external fluxes (Manning et al, 1999;Zegeye et al, 2012) and internal recycling as a result of organic matter (OM) mineralization in both the water column and underlying sediments (Katsev et al, 2006;Hupfer and Lewandowski, 2008). Removal of P through burial in sediments depends partly on sorption to iron oxides (Wilson et al, 2010), and because iron oxides tend to dissolve under reducing conditions and long-term anoxia, phosphate burial is sensitive to the oxygenation state of the water column and water-sediment interface (Sapota et al, 2006;Rothe et al, 2015). In environments with high sulfate (SO 2− 4 ) concentrations and sufficient labile OM, microbial SO 2− 4 reduction usually leads to the formation of sulfides and eventually iron sulfides, which decrease Fe recycling and the formation of Fe (oxyhydr)oxides in the upper oxygenated sediments, and this in turn decreases the extent to which P is retained in the sediment (Roden and Edmonds, 1997).…”

The microbially driven formation of siderite in salt marsh sediments

“…While there are studies looking at crystal morphology and isotopic composition of modern and ancient siderites (Abdul Hadi & Astin, ; Allison & Pye, ; Baumann et al, ; Moore, Ferrell, & Aharon, ; Raiswell & Fisher, ; Wittkop et al, ), and separate studies trying to nucleate siderite biotically or abiotically in the laboratory (Köhler, Konhauser, Papineau, Bekker, & Kappler, ; Mortimer, Galsworthy, Bittrell, Wilmot, & Newton, ; Mortimer & Coleman, ; Sanchez‐Roman et al, ), there are few studies that couple the analysis of modern siderite to laboratory experiments trying to grow it. In the East Anglian salt marshes (particularly along the north Norfolk coast, in the salt marshes named Warham, Stiffkey, and Blakeney), there are large siderite concretions (up to 20 cm in diameter) found actively growing in the sediment (Figure ).…”