Tufas and Speleothems: Unravelling the Microbial and Physical Controls
Our understanding of calcium carbonate precipitation within freshwater carbonate systems is being revolutionized by new quantitative approaches at both field and laboratory scale. These systems cover a diverse range of topical research areas including tufas, speleothems, stromatolites and microbial processes. Progress by various international research groups has been impressive, with major contributions to such areas as climate change, absolute dating, carbon sequestration, and biofilm construction and precipitation. A diverse sample of interrelated research is presented that provides a tantalizing glimpse of the interplay between microbial, geochemical and physical processes that control the development of tufas and speleothems.
This volume will provide a cross-disciplinary platform that will stimulate further exchanges about new concepts, methodologies and interpretations associated with freshwater carbonates. In particular, it will help reinforce the importance of cross-discipline research: the driving force behind the new field of Geobiology.
The fractionation of phosphorus in some modern and late-Holocene calcareous tufas in North Yorkshire, UK
-
Published:January 01, 2010
Abstract
Phosphorus fractionation studies were undertaken on seven UK tufas: three modern, and four old. The phosphorus in the carbonate fraction of the tufa averaged 19% of the total phosphorus in the modern material, and from 48–64% in the 4000 year-old deposits and the increase attributed to the mineralization of the contained organic matter. Two further phosphorus fractions contained significant amounts of P. The dithionite fraction ranged from 10–27% of the total, and most of this fraction was probably associated with detrital iron minerals. The alkali-soluble fraction which removed most of the organically-bound P was highest in the modern bryophyte tufas.
Total P levels in the tufas ranged from 33–119 ppm. These are low values for stream sediments. Phosphorus uptake rates into tufa were estimated for these sites. They were less than 5% of the incoming P and deemed to have a negligible effect on the aquatic biota.