Biogeochemistry, silica

M. A. Soukup, The Eimnology of a Eutrophic HardwaterNew England Take with Mcp or Emphasis on the Biogeochemistry of Dissolved Silica, No. 75-27-527, University Microfilms, Ann Arbor, Mich., 1975. 

Wollast, R and F. T. Mackenzie (1983), "Global Cycle of Silica", in S. R. Aston, Ed., Silicon Geochemistry and Biogeochemistry, Academic Press, New York, 39-76. 

Because diatoms play such a large role in the biogeochemistry of silicon, changes in their productivity are thought to have the potential to affect other aspects of the crustal-ocean-atmosphere factory. To consider this future, we first look at the marine silica budget. 

Conley, D. (1988) Biogenic silica as an estimate of siliceous microfossil abundance in Great Lake sediments. Biogeochemistry 6, 161-179. 

Humborg, C., Conley, D.J., Rahm, L., Wulff, F., Cociasu, A., and Ittekkot, V. (2000) Silica retention in river basins far-reaching effects on biogeochemistry and aquatic food webs in coastal marine environments. Ambio 29, 45-50. 

Kroger N. and Sumper M. (2000) The biogeochemistry of silica formation in diatoms. In Biomineralization (ed. E. Baeuerlein). Wiley, Weinheim, Germany, pp. 151-170. 

Although the exact biogeochemistry is not well understood, it is assumed that silica is preferentially leached from the feldspars, pyroxenes, amphiboles, etc. through partial (or complete) dissolution, and replacement of Si04 groups by PO4 groups takes place. Some of the silica thus dissolved may be... 

There are no published studies of silica on coral reefs. Silica minerals are not abundant on coral reefs, so the biogeochemistry of silica has been ignored. It is evident, however, from the results of our uptake experiments (we measure silica in all our experiments) that silica concentrations in the water sometimes decreases and sometimes increases. This result is probably related to whether benthic diatoms are occupying the reef surfaces. At Biosphere 2 coral reef mesocosm, silica goes through a distinct seasonal cycle related to blooms of benthic diatoms (Atkinson etal., 2001). Concentrations of silica in pore-water can also change seasonally (Falter, 1998). 

Abstract. The distribution of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in the environment has not been systematically studied in Bulgaria in spite of their negative effect on the human health. The aim of this study is to develop a cost-effective method for determination of low concentrations of PCBs and OCPs in soils. After extraction with hexane/acetone and column cleaning with silica, the analyses was performed by gas chromatography with electron-capture detector. The limit of detection is between 0.1 and 1 ng g 1, the reproducibility at low environmental levels is about 15% RSD. The analytical recoveries for the individual compounds are between 65% and 100%. The method can be applied to study the sources of pollution, the migration and biogeochemistry of PCBs in the environment. 

Soukup, M.A., "The Limnology of a Eutrophic Hardwater New England Lake, with Major Emphasis on the Biogeochemistry of Dissolved Silica, Xerox Univ. Microfilms, Ann Arbor, Michigan, Order No. 75-270527. 

A summary of the literature of silica biogeochemistry was presented by Leo and Barghoorn (4b), who discussed the cyclical movements of silica, including passage through the biosphere. ... 

Struyf, E., Conley, D.J., 2009. Silica an essential nutrient in wetland biogeochemistry. Front Ecol. Environ. View 7, 88-94. 

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