A recent paper in PNAS (1) analyzed the evolution of metalloproteins and confirmed our earlier observation on the abundance of Zn-binding proteins among the most widespread – and evolutionarily oldest – protein folds (2). As that observation appeared to contradict the extremely low (<10 M) estimates of Zn levels in the primeval anoxic ocean (3), we had suggested that the first cells developed i...

Hydrothermal chimneys and compartments comprising transition metal sulphides and associated minerals have been proposed as likely locations for the beginnings of life. In laboratory simulations of off-axis alkaline springs, it is shown that the interaction of a simulated alkaline sulphide-bearing submarine vent solution with a primeval anoxic iron-bearing ocean leads to the formation of chimney...

Glacial episodes have been linked to Ordovician-Silurian extinction events, but cooling itself may not be solely responsible for these extinctions. Teratological (malformed) assemblages of fossil plankton that correlate precisely with the extinction events can help identify alternate drivers of extinction. Here we show that metal poisoning may have caused these aberrant morphologies during a la...

The organic carbon isotope (δ13Corg) curve for ~1.7-km-thick mid-Cretaceous strata of the Chaqiela section in Gamba area, southern Tibet is presented in this study. C-isotopic chemostratigraphic correlation combined with biostratigraphic constraints show that the Chaqiela section spans early Aptian through early Campanian period, and that almost all of the carbon cycle perturbations and Oceanic...

a State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China b Department of Earth Sciences, Nanjing University, Nanjing 210093, China c Department of Geodynamics and Sedimentology, University of Vienna, A-1090 Vienna, Austria d University of Tulsa, 149 West Ridge Road, Cleveland, OK 74020, USA e Department of Geological Sciences, ...

The external phosphorus (P) loading has been halved, but the P content in the water column and the area of anoxic bottoms in Baltic proper has increased during the last 30 years. This can be explained by a temporary internal source of dissolved inorganic phosphorus (DIP) that is turned on when the water above the bottom sediment becomes anoxic. A load-response model, explaining the evolution fr...

BACKGROUND AND PURPOSE The impairment of mitochondrial respiratory function is an important problem in anoxia-reoxygenation injury in animal cells. This study investigated the role of mitochondrial calcium ions (Ca2+) in a model of anoxic incubation in isolated rat liver mitochondria. METHODS Mitochondria isolated from Wistar rat liver were subjected to anoxic incubation for 5 to 60 minutes. ...

Aerated-anoxic processes operate under the principle that small additions of oxygen to an anoxic reactor induce simultaneous nitrification and denitrification. In these systems, ammonia oxidation in the anoxic zone can easily account for 30-50% of the total nitrification in the reactor, even though the dissolve oxygen concentration is usually below detection limit. To investigate whether the ni...

continuous and lengthy droughts in previous years not only in the southern provinces of iran but also in the whole country necessitate optimized water management. indian ocean and adjacent seas in south of iran are suppliers of part of the humidity in the region and the variation on indian ocean sea surface temperature has an important role in evaporation from oceans and input humidity into atm...

The paleoenvironmental impact of the early Aptian Ocean Anoxic Event 1a (OAE 1a, ca. 121 Ma) has been investigated in detail Cismon Core (Lombardy Basin, western Tethys) by using different geochemical and micropaleontological proxies. We provide first high-resolution data benthic foraminiferal assemblages through upper Barremian - lower stratigraphic interval. Benthic foraminifera are integrate...