Microbial Dolomite Precipitation under Aerobic Conditions: Results from Brejo do Espinho Lagoon (Brazil) and Culture Experiments

“With an average δ18OSMOW of 2.31 ‰ for the pore water and δ18OPDB of 3.14 ‰ for the dolomite, the calculated temperature for the early diagenesis is 21˚C, which corresponds well to an average value observed with field measurements at this depth below the sediment/water interface.”

“With an average δ18OSMOW of 2.31 ‰ for the pore water and δ18OPDB of 3.14 ‰ for the dolomite, the calculated temperature for the early diagenesis is 21˚C, which corresponds well to an average value observed with field measurements at this depth below the sediment/water interface.”

“Nielsen et al. (1997) proposed that spheroidal dolomite in the karstified top of a Dinantian dolomite sequence, in Eastern Belgium, was bacterially induced or mediated precipitates.”

“Biofilms comprise bacteria immersed in a matrix of extracellular polymeric substances (EPS) (Riding, 2000; Decho, 2000).”

“Conversions between δOPDB and δOSMOW were calculated by using the equation in Coplen et al. (1983). The sediment and pore water isotope data are listed in Table 1.”

“Biofilms comprise bacteria immersed in a matrix of extracellular polymeric substances (EPS) (Riding, 2000; Decho, 2000).”

“0093 (Rosenbaum and Sheppard, 1986).”

“This combined information can be useful for the identification of microbial fossils and/or precipitates, such as biomarkers in carbonate sedimentary rocks (Buczynski and Chafetz, 1991; Allen et al., 2000; Reid et al., 2000; Riding, 2000).”

“Thus, a new metabolic process, aerobic respiration at the water-sediment interface, can now be included in the list of microbial factors that contribute to the precipitation of dolomite, in addition to bacterial sulfate reduction (Vasconcelos et al., 1995; Warthmann et al., 2000) and methanogenesis (Roberts et al.”

“The extracellular organic matter appears to play an important role in determining the morphology as indicated by a number of in vitro studies, which used different marine and freshwater bacterium (Castanier et al., 1999; Fujita et al., 2000; Warren et al., 2001).”

“…precipitation under Earth’s surface conditions (Vasconcelos et al., 1995; Warthmann et al., 2000) and has inspired the development of the microbial dolomite model based on a study of a modern dolomite-forming hypersaline coastal lagoon, Lagoa Vermehla, Brazil (Vasconcelos and McKenzie, 1997).”

“…environments presented the possibility to study the geochemical parameters promoting dolomite precipitation, attempts at laboratory experiments based on these actualistic studies proved to be of limited or no success in precipitating dolomite under Earth’s surface conditions (Land, 1985, 1998).”

“…of bacterial type (autotrophic or heterotrophic; marine or non-marine), carbonate morphologies mediated by microorganisms are distinguishable from inorganic precipitation (Krumbein, 1979; Buczynski and Chafetz, 1991; Chafetz and Buczynski, 1992; Knorre and Krumbein, 2000; Braissant et al., 2003).”

“Similar morphologic features, such as spheres and dumbbells, have been found in the geological record (Chafetz, 1986; Pedley, 1992; Folk, 1993; Kazmierczak and Altermann, 2002).”

“Similar morphologic features, such as spheres and dumbbells, have been found in the geological record (Chafetz, 1986; Pedley, 1992; Folk, 1993; Kazmierczak and Altermann, 2002).”

“…of bacterial type (autotrophic or heterotrophic; marine or non-marine), carbonate morphologies mediated by microorganisms are distinguishable from inorganic precipitation (Krumbein, 1979; Buczynski and Chafetz, 1991; Chafetz and Buczynski, 1992; Knorre and Krumbein, 2000; Braissant et al., 2003).”

“…environments presented the possibility to study the geochemical parameters promoting dolomite precipitation, attempts at laboratory experiments based on these actualistic studies proved to be of limited or no success in precipitating dolomite under Earth’s surface conditions (Land, 1985, 1998).”

“Using the δ18O paleotemperature equation calibrated for dolomite (Vasconcelos et al., 2005), we can calculate the diagenetic formation temperature of the dolomite from 20-23 cm depth.”

“…of bacterial type (autotrophic or heterotrophic; marine or non-marine), carbonate morphologies mediated by microorganisms are distinguishable from inorganic precipitation (Krumbein, 1979; Buczynski and Chafetz, 1991; Chafetz and Buczynski, 1992; Knorre and Krumbein, 2000; Braissant et al., 2003).”

“The extracellular organic matter appears to play an important role in determining the morphology as indicated by a number of in vitro studies, which used different marine and freshwater bacterium (Castanier et al., 1999; Fujita et al., 2000; Warren et al., 2001).”

“In specific modern hypersaline environments, sulfate-reducing bacteria apparently induce dolomite precipitation (Vasconcelos and McKenzie, 1997; van Lith et al., 2002, 2003; Wright and Wacey, 2005).”

“In specific modern hypersaline environments, sulfate-reducing bacteria apparently induce dolomite precipitation (Vasconcelos and McKenzie, 1997; van Lith et al., 2002, 2003; Wright and Wacey, 2005).”

“The extracellular organic matter appears to play an important role in determining the morphology as indicated by a number of in vitro studies, which used different marine and freshwater bacterium (Castanier et al., 1999; Fujita et al., 2000; Warren et al., 2001).”

“…aerobic respiration at the water-sediment interface, can now be included in the list of microbial factors that contribute to the precipitation of dolomite, in addition to bacterial sulfate reduction (Vasconcelos et al., 1995; Warthmann et al., 2000) and methanogenesis (Roberts et al., 2004).”

“From the d104 of the diffraction spectra, the Mg/Ca ratio of the carbonate minerals was calculated after Lumsden (1979).”

“For example, the Recent dolomitic crusts, studied by Robert N. Ginsburg and his colleagues, are reported to occur at or near the surface in an area covering hundreds of square kilometers on Andros Island, Bahamas (Shinn et al., 1965; 1969).”

“…of bacterial type (autotrophic or heterotrophic; marine or non-marine), carbonate morphologies mediated by microorganisms are distinguishable from inorganic precipitation (Krumbein, 1979; Buczynski and Chafetz, 1991; Chafetz and Buczynski, 1992; Knorre and Krumbein, 2000; Braissant et al., 2003).”

“Vasconcelos, C. and McKenzie, J.A. (1997) Microbial mediation of modern dolomite precipitation and diagenesis under anoxic conditions (Lagoa Vermelha, Rio de Janeiro, Brazil).”

“However, previous inorganic experiments result in the precipitation of spherical morphology (Malone et al. 1996; Golden et al., 2001), which implies that the morphology alone is not necessarily indicative of a biological process.”

“A mechanism for carbonate precipitation has been previously proposed for both natural environments (Ehrlich, 2002) and aerobic culture experiments (Rivadeneyra et al., 1998; 2004).”

“Ginsburg and his colleagues, are reported to occur at or near the surface in an area covering hundreds of square kilometers on Andros Island, Bahamas (Shinn et al., 1965; 1969).”

“A mechanism for carbonate precipitation has been previously proposed for both natural environments (Ehrlich, 2002) and aerobic culture experiments (Rivadeneyra et al., 1998; 2004).”

“A mechanism for carbonate precipitation has been previously proposed for both natural environments (Ehrlich, 2002) and aerobic culture experiments (Rivadeneyra et al., 1998; 2004).”

“These results link bacterial precipitation of dolomite and hydromagnesite, both of which are found in natural habitats (Renaut, 1990; Warren, 1990; Russell et al., 1999; Last and Ginn, 2005).”

“Similar morphologic features, such as spheres and dumbbells, have been found in the geological record (Chafetz, 1986; Pedley, 1992; Folk, 1993; Kazmierczak and Altermann, 2002).”

“V. marismortui (Heyrman et al., 2003) was first isolated in 1999 from the Dead Sea (Arahal et al., 1999), and was originally described as Bacillus marismortui.”

“However, previous inorganic experiments result in the precipitation of spherical morphology (Malone et al. 1996; Golden et al., 2001), which implies that the morphology alone is not necessarily indicative of a biological process.”

“V. marismortui (Heyrman et al., 2003) was first isolated in 1999 from the Dead Sea (Arahal et al., 1999), and was originally described as Bacillus marismortui.”

“Brejo do Espinho lagoon water has a typical seawater Mg/Ca molar ratio of ~ 5, indicating a seawater origin modified by evaporation and dilution processes (van Lith et al., 2002; Moreira et al., 2004).”

“These results link bacterial precipitation of dolomite and hydromagnesite, both of which are found in natural habitats (Renaut, 1990; Warren, 1990; Russell et al., 1999; Last and Ginn, 2005).”

“These results link bacterial precipitation of dolomite and hydromagnesite, both of which are found in natural habitats (Renaut, 1990; Warren, 1990; Russell et al., 1999; Last and Ginn, 2005).”

“And, (4) as hypothesized by Moreira et al. (2004), the bacterial sulfate reduction is complemented by in situ sulfide oxidation which results in pore waters being undersaturated with respect to (magnesium) calcite while remaining supersaturated with respect to dolomite.”

“Mastandrea et al. (2006) found nano-scale spheroids associated with microbial primary dolomite within a microbiolitic facies in Late Triassic carbonate platforms of southern Italy.”

“Similar morphologic features, such as spheres and dumbbells, have been found in the geological record (Chafetz, 1986; Pedley, 1992; Folk, 1993; Kazmierczak and Altermann, 2002).”

“This combined information can be useful for the identification of microbial fossils and/or precipitates, such as biomarkers in carbonate sedimentary rocks (Buczynski and Chafetz, 1991; Allen et al., 2000; Reid et al., 2000; Riding, 2000).”

“A diverse microbial population is generally involved in carbonate precipitation in natural environments, including photoautotrophic cyanobacteria and bacteria producing ammonia from the degradation of nitrogen-rich organic matter (Thompson and Ferris, 1990; Rivadeneyra et al. 2000).”

“…driven by bacterial sulfate-reducing activity occur under anoxic conditions leading to an ageing process where high Mg calcite and Ca dolomite (20 -40% Mg), which are metastable with respect to stoichiometric dolomite, would be expected to become stoichiometric dolomite (Malone et al., 1994).”

“Indeed, the same co-precipitation with similar morphology has been found in other modern environments, such as Lake Walyungup in South Australia (Rosen and Mcnamara, 1998; Coshell et al., 1998).”

“These results link bacterial precipitation of dolomite and hydromagnesite, both of which are found in natural habitats (Renaut, 1990; Warren, 1990; Russell et al., 1999; Last and Ginn, 2005).”

“Riding (2000) has suggested that morphology (microfabric) studies can provide insight on biomineralization processes, as well as on the environmental conditions where dolomite precipitates.”

“Furthermore, Mansfield (1980) reported urolitic biogenic dolomite with spheroidal structures.”

“However, it has been demonstrated recently that aerobic bacteria, whose metabolic reactions do not involve sulphate, can mediate dolomite precipitation as well, even in the presence of a sulphate concentration two times that of sea water (Sanchez-Roman et al., 2009a,b).”

“Proposedmechanisms for themicrobial precipitation of carbonates in both natural environments (Ehrlich, 2002; Vasconcelos and McKenzie, 1997; Sánchez-Román et al., 2009a) and in laboratory culture experiments (e.g., Warthmann et al., 2000; Sánchez-Román et al., 2007, 2008, 2009b) suggest…”

“…such as sulphur-oxidizing bacteria (Moreira et al., 2004), methanogens (Roberts et al., 2004), halophilic bacteria (Rivadeneyra et al., 2000, 2004; Sánchez-Román et al., 2008, 2009a), anaerobic methane oxidizing communities (Moore et al., 2004, Meister et al., 2007) and even cyanobacteria…”

“…formation is related to microbial activity (Baker and Burns, 1985; Vasconcelos and McKenzie, 1997; Wright, 1999; Garcia del Cura et al., 2001; van Lith et al., 2003a; Roberts et al., 2004; Moreira et al., 2004; Wright and Wacey, 2005; Mastandrea et al., 2006; Sánchez-Román et al., 2008, 2009a).”

“marismortui surfaces, and that later accrete to form many Ca–Mg carbonate and phosphate biominerals (Aloisi et al., 2006; Benzerara et al., 2006; Rivadeneyra et al., 2006; Bontognali et al., 2008; Sánchez-Navas et al., 2009; Sánchez-Román et al., 2009a).”

“3d), and microbialites are known to host dolomitization processes and produce finegrained dolomite (Sánchez-Román et al., 2009; Krause et al., 2012).”

“…relatively extreme conditions (Vasconcelos 1994; Vasconcelos & McKenzie 1997; van Lith et al. 2003; Moreira et al. 2004; Vasconcelos et al. 2006; Sánchez-Román et al. 2009; Bontognali et al. 2012; Delfino et al. From: Bosence, D. W. J., Gibbons, K. A., Le Heron, D. P., Morgan, W. A.,…”

“…to those observed in modern microbialites of marine (Dupraz et al., 2004), hypersaline lake (Bontognali et al., 2010; Glunk et al., 2011), freshwater (Défarge et al., 1996; Power et al., 2011; Perri et al., 2012), and evaporative tidal flat environments (Sánchez-Román et al., 2009, 2011).”

“…other types of carbonates such as aragonite, calcite and high-Mg calcite (Vasconcelos et al., 1995; Vasconcelos & McKenzie, 1997; Wacey et al., 2007; S anchez-Rom an et al., 2009a; Bontognali et al., 2010, Bontognali et al., 2012; Baldermann et al., 2015; Brauchli et al., 2016; Pace et al., 2016).”

“Other analogs with the Lagoa Vermelha sediments include early lithification phenomena and a paucity of evaporitic minerals (Sánchez-Román et al., 2009; Spadafora et al., 2010).”

“…environments, which share similarities with Early Earth environments, provide important insights into the physical and chemical processes that may have operated on Early Mars (e.g., Vasconcelos and McKenzie 1997; van Lith et al. 2002, 2003; Vasconcelos et al. 2006; Sánchez-Román et al. 2008a).”

“6H2O) have been reported from sediments rich in organic remains (Sánchez-Román et al. 2007, 2009).”

“It is likely this process leads to the observed increase of pH (S anchez-Roman et al. 2007a, 2007b), which affects precipitation of carbonate minerals as reported in other studies (Barton and Northup, 2007; Portillo et al. 2009; Portillo and Gonzalez, 2010).”

“Recently, the microbial dolomite model has been proposed to explain dolomite formation due to bacteriallymediated precipitation (Vasconcelos et al., 1995; Vasconcelos and McKenzie, 1997; Sánchez-Román et al., 2009).”

“WD-1, mainly consisting of Proteus mirabilis, was enriched from the rhodoliths composed of Mg-rich calcite on the coast in Wudo, Jeju Island [15].”

“To induce calcium carbonate precipitation following microbial urea decomposition, 20 g/L urea and 0.03 mol/L calcium chloride (CaCl 2 ·2H 2 O) were added to the medium using a 0.2 μm filter 11,42,43 .”

“The simulated experimental results are very similar to those of dolomite crystal precipitation in sediments in modern high-salinity environments [9-12].”

“Reactions involving sulphate-reducing bacteria have also been shown to stimulate dolomite precipitation in altered sea water (Vasconcelos et al., 1995; Sánchez-Román et al., 2009).”

“Many studies have shown that the peloidal microfabric and the formation of carbonate minerals with spheroidal morphology point to microbial involvement (e.g. Bontognali et al. 2010; Dupraz et al. 2004; Sánchez-Román et al. 2007, 2009).”

“Modern environments where dolomite precipitates, such as hypersaline lagoons and evaporative lakes, serve as valuable analogues for understanding the mechanisms driving dolomite formation (Sánchez-Román et al., 2009; Vasconcelos & McKenzie, 1997; Areias et al., 2022; Naim et al., 2025).”

“Among these, organic acids play a particularly critical role in converting insoluble metal compounds into soluble forms, thereby facilitating metal mobilization and uptake [32, 33].”

“…temperature and under surficial conditions is most likely mediated by microbial activity (Vas-concelos & McKenzie, 1997; S (cid:1) anchez-Rom (cid:1) an et al ., 2009a; Bontognali et al ., 2010, 2014; Pet-rash et al ., 2017; DiLoreto et al ., 2021), but clay minerals may also facilitate its…”

“…rate of bacterial growth and EPS production (Nina et al ., 2012; S (cid:2) anchez-Rom (cid:2) an et al ., 2012; Bontognali et al ., 2014; Al Disi et al ., 2017, 2019) or changes in the temperature and alkalinity of the lake water (Morrow, 1982; Van-Lith et al ., 2003; Al Disi et al ., 2017, 2019).”

“Previous laboratory research revealed that aerobic bacteria may have a role in the creation of highmagnesium calcite or dolomite, in the microenvironment around the cell (Sánchez-Román et al. 2009; Sánchez-Román et al. 2011; Al Disi et al. 2017).”

“Prior workers suggested that microbes have the potential to facilitate dolomitization in unlithified sediments (Vasconcelos et al., 1995; Vasconcelos & McKenzie, 1997; Warthmann et al., 2000; Wright & Wacey, 2005; Kenward et al., 2009; S anchez-Rom an et al., 2009; Petrash et al., 2017).”

“Certain microbes, such as sulfate-reducing bacteria (SRB), halophilic bacteria, green sulfur bacteria, cyanobacteria, and archaea, play a role in the formation of dolomite through a process known as microbial mediation [8,9,16,54–67].”