The biogeochemistry of pristine, headwater Precambrian shield watersheds: an analysis of material transport within a heterogeneous landscape

1993 ◽  
Vol 22 (1) ◽  
pp. 37-79 ◽  
Author(s):  
C. J. Allan ◽  
N. T. Roulet ◽  
A. R. Hill
Keyword(s):  
Material Transport ◽  
Precambrian Shield ◽  
Heterogeneous Landscape

Chemical and Biological Changes in Nelson Lake, Ontario Following Experimental Elevation of Lake pH

1977 ◽  
Vol 12 (1) ◽  
pp. 213-232 ◽  
Author(s):  
N.D. Yan ◽  
W.A. Scheider ◽  
P.J. Dillon
Keyword(s):  
Heavy Metal ◽  
Lake Ontario ◽  
Background Concentrations ◽  
Precambrian Shield ◽  
Metal Levels ◽  
Zooplankton Communities ◽  
Shield Lakes

Abstract Intensive studies of Nelson Lake, a Sudbury area lake of intermediate pH ~5.7), were begun in 1975. The chemistry of the lake was typical of that of most PreCambrian Shield lakes except that low alkalinities and high sulphate concentrations were observed along with elevated heavy metal levels. After raising the pH of Nelson Lake to 6.4 by addition of Ca(OH)2 and CaCO3, the metals were reduced to background concentrations. Phytoplankton and Zooplankton communities, which at pH of 5.7 were typical of PreCambrian lakes, were not affected by the experimental elevation of lake pH.

THE NEORCHEAN RECORD OF THE CANADIAN PRECAMBRIAN SHIELD: NEW PERSPECTIVES FROM THE CRUST AND LITHOSPHERE

2020 ◽  
Author(s):  
Sally Pehrsson ◽  
◽  
John Percival ◽  
Bruce Eglington ◽  
Robert Berman ◽  
...  
Keyword(s):  
Precambrian Shield

Supplemental material: Transport and biogeochemical reaction of metals in a physically and chemically heterogeneous aquifer

2020 ◽  
Author(s):  
Timothy D. Scheibe ◽  
Yilin Fang ◽  
Christopher J. Murray ◽  
Eric E. Roden ◽  
Jinsong Chen ◽  
...  
Keyword(s):  
File Size ◽  
Material Transport ◽  
Heterogeneous Aquifer ◽  
Simulation Results

Geosphere, June 2006, v. 2, p. 220-235, doi: 10.1130/GES00029.1. Animation 1 - Animation of simulation results for U(VI) contamination period (22 yr) for the Geophys2 case. Upper panel—sorbed U(VI); lower panel—aqueous U(VI). All concentrations are in molar units (M). The file size is 1.4 MB.

Supplemental material: Transport and biogeochemical reaction of metals in a physically and chemically heterogeneous aquifer

2020 ◽  
Author(s):  
Timothy D. Scheibe ◽  
Yilin Fang ◽  
Christopher J. Murray ◽  
Eric E. Roden ◽  
Jinsong Chen ◽  
...  
Keyword(s):  
File Size ◽  
Material Transport ◽  
Heterogeneous Aquifer ◽  
Simulation Results

Geosphere, June 2006, v. 2, p. 220-235, doi: 10.1130/GES00029.1. Animation 1 - Animation of simulation results for U(VI) contamination period (22 yr) for the Geophys2 case. Upper panel—sorbed U(VI); lower panel—aqueous U(VI). All concentrations are in molar units (M). The file size is 1.4 MB.

scholarly journals An Experimental Study on the Influence of Drastically Varying Discharge Ratios on Bed Topography and Flow Structure at Urban Channel Confluences

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1147
Author(s):  
Zhiyuan Zhang ◽  
Yuqing Lin
Keyword(s):  
Transition Period ◽  
Maximum Velocity ◽  
Maximum Flow ◽  
River Network ◽  
Morphological Alteration ◽  
Minor Role ◽  
Material Transport ◽  
Lateral Velocity ◽  
Basic Work ◽  
Discharge Ratio

The confluences of rivers are important nodes for energy conversion and material transport in the river network. A slight morphological alteration of the confluences may trigger the “butterfly effect”, which will bring about changes in the ecology and environment of the entire river network. During the transition period of the wet and dry seasons, the variation of discharge ratio will make the originally balanced river bed change again, which will bring a series of follow-up effects. This research mainly studied the features of water flow itself and results showed that the variation of discharge ratio caused secondary erosion of the balanced bed surface and transported the sediment downstream. Thus, the zone of maximum velocity was enlarged and the maximum flow velocity at the equal discharge was reduced, and more intense vortex and turbulence were generated. The lateral velocity, vertical velocity, and turbulent structure were mainly controlled by the quantity and ratio of the discharge, and the varying topography only played a minor role in local areas. Nowadays, some scholars have been studying the combination of flow field features and various environmental substances and biological habitats, and the basic work done in this article has laid the foundation for these studies.

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