After significant reductions in external phosphorus (P) loads, and subsequent water quality improvements in the early 1980s, the water quality of Lake Erie has declined considerably over the past decade. The frequency and magnitude of harmful algal blooms (primarily in the western basin) and the extent of hypoxic bottom waters in the central basin have increased. The decline in ecosystem health...

Agricultural applications of chemical fertilizers are a world wide practice. The specific activity of uranium-238 and heavy metals in phosphate fertilizers depends on the phosphate ore from which the fertilizer produced and on the chemical processing of the ore. Composite phosphate fertilizers samples where collected and the uranium-238 specific activity, in Bq/kg, and As, Cd, Cu, Pb, Se concen...

Adsorption of dissolved phosphate onto iron-hydroxides has been shown to be one of the primary regulators of phosphorus cycling in sediments. Bioturbation and bioirrigation by benthic infauna modify this cycling by accelerating the transport of dissolved and particulate phosphorus and by changing rates of reactions that occur in the sediment, such as the adsorption of phosphate by amorphous iro...

Abstract The traditional approach for the beneficiation of South African siliceous sedimentary phosphate ores has been reverse cationic flotation. robustness this approach, however, a concern due to its sensitivity parameters such as slimes content, headgrade (P 2 O 5 and SiO content), reagent dosages conditioning times. mineralisation ore body under investigation is predominantly carbonate flu...

During an expedition in 2014 in the Gulf of Gabes that aimed to evaluate the impact of the pollution of the phosphate industry on the marine environment, numerous dead coral fragments were retrieved from several stations along a 18 km long transect in front of the industry complex of Gabes. Detailed taxonomy of these coral fragments shows clearly that all fragments belong to the species Cladoco...

Detrital zircon studies are providing new insights on the evolution of sedimentary basins but the role of sedimentary recycling remains largely undefined. In a broad region of northwestern North America, this contribution traces the pathway of detrital zircon sand grains from Proterozoic sandstones through Phanerozoic strata and argues for multi-stage sedimentary recycling over more than a bill...

Formation of hydroxylapatite through the precipitation and evolution of calcium phosphate precursor phases under varying conditions of temperature (25–90 °C), pH (6.5–9.0), and calcium to phosphorus ratio (1.0, 1.33, 1.5, and 1.67) comparable to those found in many sediments and soils were studied. The products of low-temperature precipitation were analyzed by ex situ X-ray diffraction and SEM,...

A model for the emplacement, bioturbation, and preservation of fine scaled sedimentary strata has been used to evaluate the impact of interacting physical and biological sedimentary processes on preserved sedimentary fabric in three contrasting shelf and estuarine depositional settings: Eckernförde Bay, German Baltic Sea; the Eel Shelf, northern California, USA; and the northern Gulf of Alaska ...