Publications by authors named "Lena Lecourt"

Stromatolites are organo-sedimentary structures that represent some of the oldest records of the early biosphere on Earth. Cyanobacteria are considered as a main component of the microbial mats that are supposed to produce stromatolite-like structures. Understanding the role of cyanobacteria and associated microorganisms on the mineralization processes is critical to better understand what can be preserved in the laminated structure of stromatolites.

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Article Synopsis
  • Lake Dziani Dzaha is a unique tropical crater lake on Petite Terre Island in Mayotte, known for its diverse and actively growing stromatolites composed mainly of aragonite, magnesium-silicate, and other minerals.
  • High-throughput sequencing of microbial communities shows that the stromatolites' microbial mats are different from the lake water, with distinct Cyanobacteria types contributing to their structure and composition.
  • The study suggests that two groups of bacteria, Pleurocapsales and Alphaproteobacteria, play important roles in forming different mineral phases in the stromatolites, highlighting their significance in biogeochemical processes in the lake.
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Basalts are recognized as one of the major habitats on Earth, harboring diverse and active microbial populations. Inconsistently, this living component is rarely considered in engineering operations carried out in these environments. This includes carbon capture and storage (CCS) technologies that seek to offset anthropogenic CO emissions into the atmosphere by burying this greenhouse gas in the subsurface.

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Despite their potential importance as analogs of primitive microbial metabolisms, the knowledge of the structure and functioning of the deep ecosystems associated with serpentinizing environments is hampered by the lack of accessibility to relevant systems. These hyperalkaline environments are depleted in dissolved inorganic carbon (DIC), making the carbon sources and assimilation pathways in the associated ecosystems highly enigmatic. The Prony Bay Hydrothermal Field (PHF) is an active serpentinization site where, similar to Lost City (Mid-Atlantic Ridge), high-pH fluids rich in H and CH are discharged from carbonate chimneys at the seafloor, but in a shallower lagoonal environment.

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