Geology Commons^™

The Distribution Of Plants In Scoska Cave, North Yorkshire, And Their Relationship To Light Intensity, Allan Pentecost, Zhang Zhaohui

International Journal of Speleology

The flora of a small limestone cave was investigated. A total of 59 species was recorded (4 algae, 3 lichens, 47 bryophytes, 4 ferns, 1 angiosperm) making it bryologically the richest cave in Britain and one of the richest in Europe. All but nine of the species had been recorded from other European caves. Species-richness declined irregullarly from the entrance (relative irradiance with respect to open sky 12%) to 34m depth (rel. irradiance 0.004%). Bryophytes were found at 0-16m depth where relative irradiance declined to 0.2% and only algae were encountered at 34m depth. While irradiance, which declined exponentially, was …

Biogenic Speleothems: An Overview, Paolo Forti

International Journal of Speleology

The idea that speleothems may be somehow influenced by living organisms is rather old, but specific studies have only started in the last few decades and presently there are only a couple of systematic papers on this topic. The role of micro-organisms is perhaps the best investigated even if it is not fully understood, while studies over upper organisms and speleothems in a cavern environment are scarce and details are not always given on the involved genetic mechanisms. The aim of the present paper is to give an updated overview on these topics in order to enhance the interest of …

Flow Through Well Screens As A Function Of Pump Intake Location, Kristjan F. Bekker

Theses and Dissertations

Greater well efficiency and lower production costs may result from a knowledge of water flow through well screens. Current practice generally locates the intake of a pump in the cased section of the well above the screen. This work shows that placing the pump within the screen will increase well efficiency and therefore lower energy cost. This work also shows a correlation of increased well efficiency with respect to larger sand size, larger screen slot size, and lower flow rates.

A semicircular model based on the radial symmetry of a well and screen was used to simulate water flow from …