Organomineralization processes in freshwater stromatolites: a living example from eastern Patagonia

Autor: Vincent Martinuzzi, Gabriel Hunger, Gabriela Catalina Cusminsky, Crisogono Vasconcelos, Daniel Ariztegui, Béatrice Burdin, Kurt Barmettler, Muriel Pacton
Jazyk: angličtina
Rok vydání: 2015
Předmět:
0301 basic medicine
Stratigraphy
Geochemistry
BACTERIAL FOSSILS
Subtropics
Environmental Science (miscellaneous)
Structural basin
010502 geochemistry & geophysics
Oceanography
01 natural sciences
Ciencias de la Tierra y relacionadas con el Medio Ambiente
purl.org/becyt/ford/1 [https]
purl.org/becyt/ford/1.5 [https]
03 medical and health sciences
chemistry.chemical_compound
Altitude
NANOGLOBULES
Stromatolites
ddc:550
Patagonia
14. Life underwater
0105 earth and related environmental sciences
Calcite
biology
FRESHWATER MICROBIALITE
Paleontology
Geology
15. Life on land
biology.organism_classification
BIOMINERALIZATION
Anoxic waters
Geomicrobiology
6. Clean water
030104 developmental biology
Stromatolite
chemistry
13. Climate action
Bacterial fossils
Biomineralization
Extracellular polymeric substances
Freshwater microbialite
nanoglobules
stromatolites
Sedimentary rock
EXTRACELLULAR POLIMERIC SUSBTANCE
Meteorología y Ciencias Atmosféricas
CIENCIAS NATURALES Y EXACTAS
Zdroj: The Depositional Record, 1 (2)
Depositional Record (2016) P. 130–146
The Depositional Record
CONICET Digital (CONICET)
Consejo Nacional de Investigaciones Científicas y Técnicas
instacron:CONICET
ISSN: 2055-4877
Popis: Living stromatolites have been mostly described within shallow marine and (hyper)saline lacustrine environments. Southernmost South America lacks detailed investigations of these (organo)sedimentary buildups, particularly in regions experiencing extreme and variable environmental conditions. Here, we report and describe living freshwater stromatolites in the Maquinchao region, north‐western Patagonia, Argentina. Fossil stromatolites characterized by globular and cauliflower shapes are also present in a continuous palaeoshoreline of a former lake at an altitude of 830 m, whereas their living counterparts only occur in the calm waters of sheltered or meandering sections of the Maquinchao River. The living stromatolites and their host waters have been sampled and studied using various chemical and microscopic techniques to better constrain the environmental versus biological factors controlling their development. Our results indicate that today stromatolites only proliferate in freshwater when Ca2+ levels are high. A microscopic inspection of the living stromatolite mat indicates stronger photosynthetic activity in the upper green layer associated with crypto/microcrystalline calcite (nanoglobules) compared to the lower beige‐white biofilm. This biofilm contains more low‐Mg calcite (rhombohedra) precipitates, which can form millimetre‐sized aggregates in the underlying anoxic layer. Although sulphate‐reducing bacteria are living in the entire mat, they appear more abundant and widely distributed in the lower beige‐white layer and are always associated with Mg calcite. Low salinity and low‐turbidity water along with microbial (photosynthetic and heterotrophic) activity are the most important factors promoting low‐Mg calcite precipitation in the Maquinchao Basin. These conditions are very different from those proposed for recently described lacustrine stromatolites at high altitude in the subtropical and tropical Andes as well as in Chilean Patagonia. Hence, all these observations in modern freshwater stromatolites show the importance of geomicrobiological studies in identifying proxies of the hydrological conditions prevailing during their formation. Fil: Pacton, Muriel. Geological Institute; Suiza Fil: Hunger, Gabriel. Universidad de Ginebra; Suiza Fil: Martinuzzi, Vincent. Universidad de Ginebra; Suiza Fil: Cusminsky, Gabriela Catalina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Burdin, Beatrice. Centre technologique des microstructures; Francia Fil: Barmettler, Kurt. Institute of Biogeochemistry and Pollutant Dynamics; Suiza Fil: Vasconcelos, Crisogono. Geological Institute; Suiza Fil: Ariztegui, Daniel. Universidad de Ginebra; Suiza
Databáze: OpenAIRE
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