As we know, both cellulose oxygen isotope and leaf wax hydrogen isotope could record the isotope information of precipitation. However, for cellulose, most case studies focus on peat study. For lake sediment, there seldom papers concerned. Could you share your ideas about this? Thanks.
Your question is not any simple, Mingda.
Cellulose is more suitable moiety for your precipitation studies due to its molecular /polysacharide built from 1,4 beta-anhydro-glucopyranose units with average polymerization degree n aprox. 102 to 104 / and supramolecular structure /it contains as amorphous so cristalline portions/.
Crystalline areas of cellulose represent a high ordered structures that are an obstacle for chemical, biochemical and enzymatic agents- with exception of white rot fungi and molds.
Amorphous areas of cellulose fibrilles are less resistant, due to orderless structure of this portion easy to interact with water /swelling/ and chemicals.
As for the leaf waxes , generally hydrophobic, these are despite their low polarity less stabile, especially in alkaline environment, and sometimes more apt to chemical and biochemical degradation /some strains of ascomytes, bacterias....... /.
A big advantage of cellulose to leaf waxes is its much larger abundance in the nature. Most of degradation reactions in lake sediment proceed under almost un-aerobic conditions. From this reason, degradadion of cellulose and leaf waxes via aerobic agents /most of biotic agents /fungi, molds.../ is almost excluded.
R.S.
During synthesis of cellulose, sucrose cound exchange oxygen atoms with water, so oxygen isotope in cellulose can not reflect oxygen isotope in leaf water completely, but for D in wax, no exchagne between substrate and water during wax synthesis.
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