The presence of many metals at trace or ultra-trace levels in the human environment has received increased global attention (WHO 1977; Hutton 1982; IRPTC 1984). Surveillance of concentrations of heavy metals in the environment is of global interest since elements like cadmium, lead and mercury are listed as environmenta]ly dangerous chemical substances. Sediments as a sink for pollutants are wi...

A radioisotope method was devised to study bacterial respiratory reduction of arsenate in sediments. The following two arsenic-rich soda lakes in California were chosen for comparison on the basis of their different salinities: Mono Lake (approximately 90 g/liter) and Searles Lake (approximately 340 g/liter). Profiles of arsenate reduction and sulfate reduction were constructed for both lakes. ...

introduction urmia lake in the northwestern corner of iran is one of the largest permanent hyper saline lakes in the world and the largest lake in the middle east. it is extended as much as 140 km from north to south and is as wide as 85 km east to west during high water periods. qualitative and quantitative degradation of water resources is one of the major challenges in the way of sustainable...

Chmiel, H. E. 2015. The role of sediments in the carbon cycle of boreal lakes. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 1279. 42 pp. Uppsala: Acta Universitatis Upsaliensis. ISBN 978-91-554-9318-9. Inland waters are active sites of carbon (C) processing and emitters of carbon dioxide (CO2) and methane (CH4) to the atmosphere. In the bor...

Quantitative analysis of siliceous microfossils in 210Pb-dated Lake Michigan sediments shows five time zones in microfossil abundance and composition. Sediments deposited before 1885 contain low abundances comprising species associated with very oligotrophic lakes. Between 1885 and 1925 abundance increases slowly as does the ratio of planktonic diatoms to benthic diatoms and chrysophyte remains...

To understand the nitrogen (N) cycle in sediments with deep oxygen penetration, we measured pore-water profiles to calculate N fluxes and rates at 13 locations in Lake Superior in water depths ranging from 26 to 318 m. Sediments with high oxygen demand, such as in nearshore or high-sedimentation areas, contribute disproportionally to benthic N removal, despite covering only a small portion of t...

Sedimentary records of plant-wax hydrogen (dDwax) and carbon (d Cwax) stable isotopes are increasingly applied to infer past climate change. Compound-specific radiocarbon analyses, however, indicate that long time lags can occur between the synthesis of plant waxes and their subsequent deposition in marginal marine sediments. The influence of these time lags on interpretations of plant-wax stab...