scholarly journals Biogenicity inferred from microbialite geochemistry

2004 ◽  
Vol 25 (1) ◽  
pp. 34 ◽  
Author(s):  
Gregory E Webb ◽  
Balz S Kamber
Keyword(s):  
Rare Earth ◽  
Trace Metals ◽  
Rare Earth Elements ◽  
Great Barrier Reef ◽  
Carbonate Rocks ◽  
Metal Cations ◽  
Microbial Processes ◽  
Barrier Reef ◽  
Carbonate Minerals ◽  
High Concentrations

Microbes utilise and/or concentrate diverse metal cations, whose detection may become a potent tool for reconstructing microbial processes and, in particular, for establishing the genesis of ancient carbonate rocks that were produced by microbes. Such rocks, termed microbialites, consist of trapped and bound sediment and, importantly, carbonate minerals precipitated as accidental byproducts of metabolic or decay processes within biofilms. Where trace metals are predictably incorporated into microbialites, they may reflect biofilm processes and allow interpretation of preserved carbonates. Holocene (about 5-6,000 years old) microbialites that formed in reef cavities in the Great Barrier Reef (GBR) faithfully incorporated high concentrations of rare earth elements and yttrium proportional to their abundance in shallow seawater. Ancient microbialites display similar behaviour.

Rare earth elements in the terminal Ediacaran Bambuí Group carbonate rocks (Brazil): evidence for high seawater alkalinity during rise of early animals

2020 ◽  
Vol 336 ◽  
pp. 105506 ◽  
Author(s):  
Gustavo Macedo Paula-Santos ◽  
Sergio Caetano-Filho ◽  
Jacinta Enzweiler ◽  
Margareth S. Navarro ◽  
Marly Babinski ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Carbonate Rocks

Low concentrations of methaemoglobin in marine fishes of the Great Barrier Reef, Australia

1997 ◽  
Vol 48 (4) ◽  
pp. 303 ◽  
Author(s):  
Rufus M. G. Wells ◽  
John Baldwin ◽  
Roger S. Seymour
Keyword(s):  
Great Barrier Reef ◽  
Marine Fish ◽  
High Water ◽  
Barrier Reef ◽  
Multiple Wavelength ◽  
Low Concentrations ◽  
Derivative Method ◽  
In Captivity ◽  
Total Haemoglobin ◽  
High Concentrations

Concentrations of methaemoglobin (the oxidized non-functional ferric form of haemoglobin) in the blood of marine fish are poorly documented. Although high concentrations have been reported for fish maintained in captivity, baseline values for wild populations are unknown. Two techniques, the cyanide derivative method and the multiple wavelength method, were used to determine methaemoglobin concentrations in blood samples from 25 species of marine teleosts and elasmobranchs captured on the Australian Great Barrier Reef. Although methaemoglobin generally accounted for less than 2% of total haemoglobin, systematic errors occurred when these two standard methods, developed for mammalian blood, were applied to the blood of some fish species. Most problems arose from reactions of various blood components with the reagents used in the cyanide derivative method. Consequently, the multiple wavelength method generally was more reliable for estimating methaemoglobin in the blood of marine fish. The low methaemoglobin concentrations in fish studied on the Great Barrier Reef indicate high water quality and healthy physiological condition.

scholarly journals Atmospheric Trace Metal Deposition near the Great Barrier Reef, Australia

Atmosphere ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 390 ◽  
Author(s):  
Michal Strzelec ◽  
Bernadette C. Proemse ◽  
Melanie Gault-Ringold ◽  
Philip W. Boyd ◽  
Morgane M. G. Perron ◽  
...  
Keyword(s):  
Trace Metals ◽  
Great Barrier Reef ◽  
Marine Ecosystem ◽  
Precipitation Event ◽  
Deposition Flux ◽  
Barrier Reef ◽  
Combustion Emissions ◽  
Leaching Experiments ◽  
Aerosol Sources ◽  
Delivery Mechanism

Aerosols deposited into the Great Barrier Reef (GBR) contain iron (Fe) and other trace metals, which may act as micronutrients or as toxins to this sensitive marine ecosystem. In this paper, we quantified the atmospheric deposition of Fe and investigated aerosol sources in Mission Beach (Queensland) next to the GBR. Leaching experiments were applied to distinguish pools of Fe with regard to its solubility. The labile Fe concentration in aerosols was 2.3–10.6 ng m−3, which is equivalent to 4.9%–11.4% of total Fe and was linked to combustion and biomass burning processes, while total Fe was dominated by crustal sources. A one-day precipitation event provided more soluble iron than the average dry deposition flux, 0.165 and 0.143 μmol m−2 day−1, respectively. Scanning Electron Microscopy indicated that alumina-silicates were the main carriers of total Fe and samples affected by combustion emissions were accompanied by regular round-shaped carbonaceous particulates. Collected aerosols contained significant amounts of Cd, Co, Cu, Mo, Mn, Pb, V, and Zn, which were mostly (47.5%–96.7%) in the labile form. In this study, we provide the first field data on the atmospheric delivery of Fe and other trace metals to the GBR and propose that this is an important delivery mechanism to this region.

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