Journal Article

Biomineralization of amorphous Fe-, Mn- and Si-rich mineral phases by cyanobacteria under oxic and alkaline conditions

UNIVERSIDAD NACIONAL AUTONOMA DE MEXICO DEPARTAMENTO DE ECOLOGIA Y RECURSOS NATURALES MEX ; Partenaires IRSTEA ; Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Tavera, Rosaluz, Iniesto, Miguel, Ciobanu, Maria, Benzerara, Karim, “SAMBA” project, Interrvie program, European Project: 787904,PLAST-EVOL, Thomazo, Christophe, Skouri-Panet, Fériel, Biogéosciences [UMR 6282] (BGS) ; Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Moreira, David, ANR-18-CE02-0013,Microbialites,Déterminants biogéochimiques de la formation des microbialites, Synchrotron SOLEIL, L’Orme des Merisiers, BP 48, Saint-Aubin, 91192 Gif-sur-Yvette, France, European Project: 307110,Calcyan, Menguy, Nicolas, Bertolino, Paola, Elmaleh, Agnès, López-García, Purificación, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC) ; Muséum national

2023

Overview

Iron and manganese are poorly soluble elements in oxic and alkaline solutions, whereas they are much more soluble under anoxic conditions. As a result, the formation of authigenic mineral phases rich in Fe and/or Mn has traditionally been viewed as diagnostic of global or local anoxic conditions. Here we reveal that some specific cyanobacteria of very small size (< 2 µm, i.e., picocyanobacteria) can biomineralize abundant, authigenic Fe(III)-, Mn(IV)- and Si-rich amorphous phases under oxic conditions in an alkaline lake in Mexico. The resulting biominerals cluster as small globules arranged as rings around the division septum of cyanobacterial cells. These rings are enveloped within an organic, likely polysaccharidic envelope and are partially preserved, at least morphologically, upon sedimentation. Based on their 16S rDNA sequence, these cyanobacteria were affiliated with the Synechococcales order. The high Fe and Mn enrichment of the biominerals questions the systematic inference of anoxic conditions based on their detection. Moreover, this process scavenges iron from the water column, an overlooked biological contribution to the Fe cycle. Finally, it reveals a new case of controlled biomineralization of Si-rich phases by bacteria.

• Publisher: European Geosciences Union,HAL CCSD,Copernicus GmbH,Copernicus Publications
• Subject: Anoxia / Anoxic conditions / Bacteriology / Bioavailability / Biodiversity and Ecology / Chlorophyll / Continental interfaces, environment / Cyanobacteria / Earth Sciences / Environmental Sciences / Geochemistry / Globules / Iron / Lakes / Lasers / Life Sciences / Manganese / Microbiology and Parasitology / Mineralization / Mineralogy / Oxic conditions / Phases / Pore size / rRNA 16S / Sciences of the Universe / Sensors / Water circulation / Water column