“…Nevertheless, an indirect marine influence could be possible by aerosols, which can be significant in arid environments. This mechanism has been described in present-day Australian lakes (Bird et al 1989;Alpers et al 1992;Bowen and Benison 2009). The environment of these modern lakes is consistent with the arid and warm conditions described for the Early Triassic, and many of them have acidic water compositions from which alunite-jarosite minerals are currently being precipitated (Alpers et al 1992).…”
Aluminum-phosphate-sulfate (APS) minerals, formed during early diagenesis in relation to acid meteoric waters, are the main host of Sr and S in the Early-Middle Triassic continental sandstones of the Iberian Ranges (east of the Iberian Peninsula). The sources of these elements and the effects of paleoenvironmetal changes on these sources and on the formation of APS minerals during Early-Middle Triassic times, were established on the basis of Sr and S isotopic analyses.The S and Sr data (d 34 S V-CDT = +11 to +14% and 87 Sr/ 86 Sr = 0.7099-0.7247, respectively) can be interpreted as resulting from mixing of different sources. Strontium was sourced from the dissolution of pre-existing minerals like K-feldspar and clay minerals inherited from the source areas, causing high radiogenic values. However, the isotopic signal must also be influenced by other sources, such as marine or volcanic aerosol that decreased the total 87 Sr/ 86 Sr ratios. Marine and volcanic aerosols were also sources of sulfur, but the d 34 S was lowered by dissolution of pre-existing sulfides, mainly pyrite. Pyrite dissolution and volcanic aerosols would also trigger the acid conditions required for the precipitation of APS minerals.APS minerals in the study area are found mainly in the Cañizar Formation (Olenekian?-Aegian), which has the lowest 87 Sr/ 86 Sr ratios. The lower abundance of APS minerals in the Eslida Formation (Aegian-Pelsonian) may indicate change in the acidity of pore water towards more alkaline conditions, while the increased 87 Sr/ 86 Sr ratios imply decreased Sr input from volcanic activity and/or marine aerosol inputs during Anisian times. Therefore, the decrease in abundance of APS minerals from the Early to Middle Triassic and the variations in the sources of Sr and S are indicative of changes in paleoenvironmental conditions during the beginning of the Triassic Period.These changes from acid to more alkaline conditions are also coincident with the first appearance of carbonate paleosols, trace fossils, and plant fossils in the upper part of the Cañizar Formation (and more in the overlying Eslida Formation) and mark the beginning of biotic recovery in this area. The presence of APS minerals in other European basins of the Western Tethys (such as the German Basin, the Paris Basin and the southeastern France and Sardinia basins) could thus also indicate that unfavorable environmental conditions caused delay in biotic recovery in those areas. In general, the presence of APS minerals may be used as an indicator of arid, acidic conditions unfavorable to biotic colonization.
“…Nevertheless, an indirect marine influence could be possible by aerosols, which can be significant in arid environments. This mechanism has been described in present-day Australian lakes (Bird et al 1989;Alpers et al 1992;Bowen and Benison 2009). The environment of these modern lakes is consistent with the arid and warm conditions described for the Early Triassic, and many of them have acidic water compositions from which alunite-jarosite minerals are currently being precipitated (Alpers et al 1992).…”
Aluminum-phosphate-sulfate (APS) minerals, formed during early diagenesis in relation to acid meteoric waters, are the main host of Sr and S in the Early-Middle Triassic continental sandstones of the Iberian Ranges (east of the Iberian Peninsula). The sources of these elements and the effects of paleoenvironmetal changes on these sources and on the formation of APS minerals during Early-Middle Triassic times, were established on the basis of Sr and S isotopic analyses.The S and Sr data (d 34 S V-CDT = +11 to +14% and 87 Sr/ 86 Sr = 0.7099-0.7247, respectively) can be interpreted as resulting from mixing of different sources. Strontium was sourced from the dissolution of pre-existing minerals like K-feldspar and clay minerals inherited from the source areas, causing high radiogenic values. However, the isotopic signal must also be influenced by other sources, such as marine or volcanic aerosol that decreased the total 87 Sr/ 86 Sr ratios. Marine and volcanic aerosols were also sources of sulfur, but the d 34 S was lowered by dissolution of pre-existing sulfides, mainly pyrite. Pyrite dissolution and volcanic aerosols would also trigger the acid conditions required for the precipitation of APS minerals.APS minerals in the study area are found mainly in the Cañizar Formation (Olenekian?-Aegian), which has the lowest 87 Sr/ 86 Sr ratios. The lower abundance of APS minerals in the Eslida Formation (Aegian-Pelsonian) may indicate change in the acidity of pore water towards more alkaline conditions, while the increased 87 Sr/ 86 Sr ratios imply decreased Sr input from volcanic activity and/or marine aerosol inputs during Anisian times. Therefore, the decrease in abundance of APS minerals from the Early to Middle Triassic and the variations in the sources of Sr and S are indicative of changes in paleoenvironmental conditions during the beginning of the Triassic Period.These changes from acid to more alkaline conditions are also coincident with the first appearance of carbonate paleosols, trace fossils, and plant fossils in the upper part of the Cañizar Formation (and more in the overlying Eslida Formation) and mark the beginning of biotic recovery in this area. The presence of APS minerals in other European basins of the Western Tethys (such as the German Basin, the Paris Basin and the southeastern France and Sardinia basins) could thus also indicate that unfavorable environmental conditions caused delay in biotic recovery in those areas. In general, the presence of APS minerals may be used as an indicator of arid, acidic conditions unfavorable to biotic colonization.
“…The Australian landscape is old, weathered and has included soils with high levels of salinity and alkalinity for at least the last 2-4 Ma [14,15,23]. Acacia has evolved in this landscape for 25 Ma and has repeatedly adapted to saline and/ or alkaline soils, in many lineages and at different times.…”
Section: Discussionmentioning
confidence: 99%
“…Acacia species richness and endemicity have been linked to soil chemistry in Western Australia [14] where large localized spatial and seasonal variability in EC and pH [15] create a mosaic of island-like niches. We investigate the evolution of salt-and alkaline-tolerance using a comprehensive Acacia phylogeny.…”
Saline or alkaline soils present a strong stress on plants that together may be even more deleterious than alone. Australia's soils are old and contain large, sometimes overlapping, areas of high salt and alkalinity. Acacia and other Australian plant lineages have evolved in this stressful soil environment and present an opportunity to understand the evolution of salt and alkalinity tolerance. We investigate this evolution by predicting the average soil salinity and pH for 503 Acacia species and mapping the response onto a maximum-likelihood phylogeny. We find that salinity and alkalinity tolerance have evolved repeatedly and often together over 25 Ma of the Acacia radiation in Australia. Geographically restricted species are often tolerant of extreme conditions. Distantly related species are sympatric in the most extreme soil environments, suggesting lack of niche saturation. There is strong evidence that many Acacia have distributions affected by salinity and alkalinity and that preference is lineage specific.
“…Hypersaline lakes are considered as extreme environments for microbial life (Bowen et al 2009). Halophiles can be found in a wide range of environments from low-saline marine environments to hypersaline lakes.…”
Culture dependent phenotypic characterization and 16S rDNA based phylogenetic analyses were applied to study the aerobic halophilic bacterial population present in the Pulicat brackish-water Lake of India. Five different media were employed for isolation of bacteria. A total of 198 morphotypes were recovered, purified and screened for salt tolerance in nutrient agar medium amended with 5-25% NaCl. Based on 16S rDNA restriction fragment length polymorphism analysis with three restriction endonucleases, 51 isolates tolerant to 5% or more NaCl were grouped into 29 clusters. Phylogenetic analysis using 16S rRNA gene sequences revealed that 29 strains could further be allocated into two clades: 19 to Firmicutes and 10 to γ-Proteobacteria. Firmicutes included low G+C Gram-positive bacteria related to family Bacillaceae, which included five genera Bacillus, Virgibacillus, Rummelibacillus, Alkalibacillus and Halobacillus. Another genera included in Firmicutes was Salimicrobium halophilum. In the γ-Proteobacteria group, all the isolates belonged to one genus Halomonas, represented by six different species Halomonas salina, H. shengliensis, H. salifodinae, H. pacifica, H. aquamarina and H. halophila. Most of the isolates exhibited cellulase, xylanase, amylase and protease activities.
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