EGU24-19036, updated on 11 Mar 2024
https://doi.org/10.5194/egusphere-egu24-19036
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Role of extracellular polymeric substances (EPS) in mineral precipitation in the ocean water column

Francisca Martinez-Ruiz1, Adina Paytan2, Crisogono Vasconcelos3, Fadwa Jroundi4, Maria del Mar Abad4, Victor Villasante, and Maria Teresa Gonzalez-Muñoz
Francisca Martinez-Ruiz et al.
  • 1Instituto Andaluz de Ciencias de la Tierra (CSIC-Univ. Granada) Granada, Spain (fmruiz@ugr.es)
  • 2Earth and Planetary Science, University of California Santa Cruz, USA (apaytan@ucsc.edu)
  • 3Center of Applied Geosciences of the Geological Survey of Brazil (CGA-SGB), Rio de Janeiro, Brazil (crisogono.vasconcelos@sgb.gov.br)
  • 4Department of Microbiology, University of Granada, Spain (fadwa@ugr.es, mgonzale@ugr.es)

The investigation of mechanisms involved in barite formation in the mesopelagic zone has served to demonstrate the importance of extracellular polymeric substances (EPS) in promoting microenvironments in which Ba can precipitate. Barite formation in the ocean was not fully understood until experimental work and observations from microenvironments of intense organic matter mineralization in the ocean water column demonstrated the role of bacteria and EPS in concentrating Ba. The organomineralization processes leading to barite formation are expected to be similar to those involved in the formation of other biominerals in which bacterial cells and EPS provide charged surfaces that bind metals inducing mineralization. Thus, EPS production plays a major role in promoting locally high concentrations of Ba leading to barite precipitation. Regarding the crystallization pathway, scanning and high-resolution transmission electron microscopy analyses have shown the occurrence of P-rich amorphous precursor phases, which supports that phosphate groups in EPS and bacterial cells are the main sites for binding Ba. These P-rich amorphous particles evolve into poorly crystallized barite and eventually into micrometer-sized barite crystals. The ubiquitous presence of bacteria and EPS in aquatic systems, and in the mesopelagic zone at depths of intense organic matter mineralization, and their inherent ability to biomineralize, make them extremely important agents in driving the Ba biogeochemical cycle. Thus, further investigating microbial processes in the open ocean is essential to better understand metal cycling. The strong link between organo-mineralization and microbial processes further supports the microbial role in biogeochemical cycles. Other than Ba, EPS may also play an important role in concentrating other metals in seawater, which still needs further investigation.

How to cite: Martinez-Ruiz, F., Paytan, A., Vasconcelos, C., Jroundi, F., Abad, M. M., Villasante, V., and Gonzalez-Muñoz, M. T.: Role of extracellular polymeric substances (EPS) in mineral precipitation in the ocean water column, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19036, https://doi.org/10.5194/egusphere-egu24-19036, 2024.