Microbial community composition and dolomite formation in the hypersaline microbial mats of the Khor Al-Adaid sabkhas, Qatar

Diloreto, Zach; Bontognali, Tomaso R. R.; Disi, Zulfa Al; Al-Kuwari, Hamad Al-Saad; Williford, Kenneth H.; Strohmenger, Christian J.; Sadooni, Fadhil N.; Palermo, Christine N.; Rivers, John M.; McKenzie, Judith A.; Tuite, Michael; Dittrich, Maria

doi:10.1007/s00792-018-01074-4

Cited by 41 publications

(39 citation statements)

References 82 publications

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“…However, such a comparison was made in a recent study on dolomite formation within natural microbial mats colonizing some hypersaline ponds in the sabkhas of Qatar (Fig. 1) (DiLoreto et al, 2019). Consistent with what is observed in the experiments of Daye et al, that study has revealed the presence of ordered dolomite in mats whose uppermost layer was dominated by anoxygenic phototrophs (Fig.…”

supporting

confidence: 81%

“…Dolomite [CaMg(CO 3 ) 2 ] is abundant in ancient rocks and rare in younger ones; why is unclear. Evidence is now emerging (Daye et al, 2019, p. 509 in this issue of Geology) that primitive microbes can mediate the formation of dolo mite, and they apparently do it better than their younger and more-evolved descendants (DiLoreto et al, 2019). If this is only a coincidence, it is an intriguing one!…”

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confidence: 99%

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Anoxygenic phototrophs and the forgotten art of making dolomite

Bontognali

2019

Geology

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supporting

confidence: 81%

mentioning

confidence: 99%

Anoxygenic phototrophs and the forgotten art of making dolomite

Bontognali

2019

Geology

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“…With the exception of one Holocene and one Miocene sediment samples (IT1, 25-2-23), archeol is not a major component of any of the sediment we analyzed (Figure 4C). Studies suggest that while salinity may be higher than the average seawater in Sabkha environments, it varies from 40 to 150 psu (Słowakiewicz et al, 2016;DiLoreto et al, 2019). Hypersaline conditions only start at 60 psu (Por, 1980) and previous work has shown that below 50 psu archeol levels are variable (Turich and Freeman, 2011).…”

Section: Isoprenoid Gdgts In Sabkha Samplesmentioning

confidence: 95%

“…In lakes, values above 67% in the GDGT-0% index (i.e., GDGT-0/Crenarchaeol ratios > 2) are typically considered as being dominated by archaeal methanogenesis (Blaga et al, 2009;Sinninghe Damsté et al, 2012). This suggests that in Sabkha sediments GDGT-0 is produced by methanogenic archaea, which are known to be abundant in this environments (DiLoreto et al, 2019). The upper most (modern) Sabkha samples have MI values of 0.29 and 0.40, respectively, which are similar to modern day open ocean sediments ( Figure 5A).…”

Section: Isoprenoid Gdgts In Sabkha Samplesmentioning

confidence: 99%

Distribution of Glycerol Dialkyl Glycerol Tetraethers (GDGTs) in Microbial Mats From Holocene and Miocene Sabkha Sediments

2019

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Sabkhas are important settings for understanding early earth biological environments, and the algal mats associated with them are thought to be potential source rocks for hydrocarbon production. In this study we compare the sedimentological facies and distribution of branched, and isoprenoid glycerol dialkyl glycerol tetraethers (GDGTs) in modern and mid-Holocene sabkha sediments from Abu Dhabi with well-preserved Miocene (12-13 Ma) sabkha sediments recently recovered at IODP site U1464 off the north coast of Australia. We show that the facies of the Miocene sediments is very similar to Holocene and modern sabkhas. Furthermore, we show that there are distinct patterns of isoprenoid GDGT distributions in the modern sabkha and that these patterns are well preserved in both the buried Holocene and the Miocene algal mats. The sabkha sediments analyzed are characterized by high %GDGT-0 and methane index, dominance of branched GDGTs over crenarchaeol (high BIT index), an unusual distribution of isoprenoid GDGTs 1-3, and also low abundance of archeol. The distribution of branched GDGT differs between modern and Miocene sabkhas and is similar in Miocene sabkha and non-sabkha sediments suggesting that they may be of limited use to distinguish paleo-sabkha sediments. Overall, isoprenoid GDGT distributions appear to be different from those found in modern soils, lakes and marine sediments, as well as from those found in Miocene shallow water sediments right below the sabkha, therefore they could be used in combination with facies analysis to identify paleo-sabkha environments in sedimentary sequences.

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“…In contrast to the vast literature related to the precipitation of Ca-carbonates and Ca-Mg-carbonates by living organisms [4,[19][20][21][22][23][24][25][26][27], the biomineralization of Mg-carbonates has been studied to a far lesser extent [12]. However, this process can provide important insights into dolomite formation and can be key to understanding the fundamental mechanisms of the evolution of the biosphere in the early stages of its development [1].…”

Section: Introductionmentioning

confidence: 99%

Mg-Rich Authigenic Carbonates in Coastal Facies of the Vtoroe Zasechnoe Lake (Southwest Siberia): First Assessment and Possible Mechanisms of Formation

et al. 2019

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The formation of Mg-rich carbonates in continental lakes throughout the world is highly relevant to irreversible CO2 sequestration and the reconstruction of paleo-sedimentary environments. Here, preliminary results on Mg-rich carbonate formation at the coastal zone of Lake Vtoroe Zasechnoe, representing the Setovskiye group of water bodies located in the forest-steppe zone of Southwest Western Siberia, are reported. The Setovskiye lakes are Cl−–Na+–(SO42−) type, alkaline, and medium or highly saline. The results of microscopic and mineralogical studies of microbialites from shallow coastal waters of Lake Vtoroe Zasechnoe demonstrated that Mg in the studied lake was precipitated in the form of hydrous Mg carbonates, which occur as radially divergent crystals that form clusters in a dumbbell or star shape. It is possible that hydrous Mg carbonate forms due to the mineralization of exopolymeric substances (EPS) around bacterial cells within the algal mats. Therefore, the Vtoroe Zasechnoe Lake represents a rare case of Mg-carbonates formation under contemporary lacustrine conditions. Further research on this, as well as other lakes of Setovskiye group, is needed for a better understanding of the possible role of biomineralization and abiotic mechanisms, such as winter freezing and solute concentration, in the formation of authigenic Mg carbonate in modern aquatic environments.

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Microbial community composition and dolomite formation in the hypersaline microbial mats of the Khor Al-Adaid sabkhas, Qatar

Cited by 41 publications

References 82 publications

Anoxygenic phototrophs and the forgotten art of making dolomite

Anoxygenic phototrophs and the forgotten art of making dolomite

Distribution of Glycerol Dialkyl Glycerol Tetraethers (GDGTs) in Microbial Mats From Holocene and Miocene Sabkha Sediments

Mg-Rich Authigenic Carbonates in Coastal Facies of the Vtoroe Zasechnoe Lake (Southwest Siberia): First Assessment and Possible Mechanisms of Formation

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