Carbon Stable Isotope Analyses of Mosses—Comparisons of Bulk Organic Matter and Extracted Nitrocellulose

The commonly used technique for determination of plant stable carbon isotope composition is analysis of CO2 liberated during combustion of chemically extracted nitrocellulose or α-cellulose. The δ13C of cellulose is usually accepted as a more reliable record of growth environment conditions compared with bulk plant material analysis. Unfortunately, cellulose extraction techniques are time-consuming, and usually require toxic chemicals such as toluene, chloroform, benzene, methanol, concentrated acids, etc. We tested the possibility of replacing nitrocellulose analysis with bulk organic analysis. Sphagnum and Polytrichum mosses collected along a vertical transect (altitudes 500 to 1400 m), provided material for analysis in the wide range of δ13C: −32.66‰ and −26.20‰ for bulk organic matter and −24.11‰ and −31.86‰ for nitrocellulose. The correlation for δ13C value of extracted cellulose and δ13C values of bulk organic matter were very good (>0.95). Our results suggested that δ13C analyses can be performed on bulk plant material instead of cellulose, without significant loss of information, at least for Polytrichum and Sphagnum mosses. Moreover, we confirmed that the extraction process of nitrocellulose did not cause any significant isotopic fractionation.