Saccone, L.; Conley, D.J.; Sauer, D. 2005. Methodologies for amorphous silica analysis. Journal of Geochemical Exploration 88.
Problem statement. There are many different silicates in the soil Si pool, including BSi. The authors refer to Si which dissolves in a study – including BSi – as amorphous Si (ASi). In the soil sciences, there is no standard technique to measure ASi. Also, density separation + dissolution (Herbauts et al. 1994) is time consuming.
Goals. To develop a universal extraction technique which can be used in terrestrial and aquatic studies, and to test different methods.
Study area. Forest soils from SW Germany, Grassland soils from W USA, and horsetail plants.
Methods. Use of the DeMaster (1981) alkali dissolution technique. Samples are dissolved in 1% Na2CO3 at 85˚C. 30 mg of sample in 40 ml of Na2CO3. Subsamples were taken hourly. There was no mention of excluding certain soil size fractions – check DeMaster (1981). Two analyses were performed: raw vs. pre-cleaned. Pre-cleaning of the samples involved sonicating and digesting with (30%?) H2O2 and 10% HCl (suggested by Mortlock & Froelich 1989). Molybdate blue method. Also test other dissolution methods.
Results. A rapid digestion of phytoliths were observed within the first 3 hours (Fig. 2) – similar to that of diatoms (DeMaster 1981). Pre-cleaned samples show a much larger Si concentration (Fig. 3). Other methods yielded significantly less SiO2.
Benefits and limitations. This study is the first to show that pre-cleaning is important. Does not report if pre-cleaning effects the ASi chemically. Does pre-cleaning make other silicates in the sample more prone to dissolution as well?
Conclusions. Pre-cleaning removes authigenic (a constituent of rock) aluminosilicate phases, allowing ASi to be more readily dissolved.
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Problem Statement: You're unemployed
Goal: Get a job
Study Area: Who cares
Method: Just do it
Result: You stop posting things on the web that no one ever reads
Benefits and Limitations: Obvious
Conclusion: Not yet determined
Problem statement: you don't understand my postings, therefore you think no one ever reads them.
Goal: Read the article.
Study area. Your desk.
Method. Using your eyes, scan the article in a sequential manner, from left to right, making note of each character. Synthesize the information your eyes have gathered.
Benefits and limitations. People will think you are smart when they see you reading such a dense article.
Conclusions. Understanding that many of the posts on this blog require prior reading is paramount. This is not explicitly stated in the blog. Rather, the author just thought it was a no-brainer. It is also implicit that certain individuals will not be able to comprehend these postings; namely people who went to the University of Dayton.
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