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Title: Peatland organic matter quality varies with latitude as suggested by combination of FTIR and Ramped Pyrolysis Oxidation
We employed two compelling and distinct methods, Fourier Transform Infrared Spectroscopy (FTIR) and Ramped Pyrolysis Oxidation (Ramped PyrOx), to examine the quality of organic matter (OM) stored in four peatlands located along a latitudinal gradient (Tropical (4˚N), Subtropical (27˚N), Boreal (48˚N), and Polar (68˚N)). FTIR was used to quantify the relative abundance of carbohydrates, a relatively labile compound class, and aromatics, which are more recalcitrant, in a sample set of four peat cores. These samples were then prepared using Ramped PyrOx, a second, independent method of determining OM quality that mimics the natural diagenetic maturation of OM that would take place over long timescales. Previous large-scale studies using FTIR to evaluate OM quality have observed that it generally increases with increasing latitude (more carbohydrates, less aromatics). Here, we demonstrate that the Ramped PyrOx approach both validates and complements the FTIR approach. The data stemming from each Ramped PyrOx preparation was input to a model that generates an estimated probability density function of the activation energy (E) required to break the C bonds in the sample. We separated these functions into three fractions (“lowE,” “mediumE,” and “highE”) to create Ramped PyrOx variables that could be quantitatively compared to the compound class abundance data from FTIR. In assessing the agreement between the two methods, we found three significant relationships between Ramped PyrOx and FTIR variables. LowEfractions and carbohydrate content were positively correlated (R2= 0.51) while lowEfractions were negatively correlated with aromatic content (R2= 0.58). MediumEfractions were found to be positively correlated with aromatics (R2= 0.69).  more » « less
Award ID(s):
2048351
PAR ID:
10595341
Author(s) / Creator(s):
; ; ; ;
Editor(s):
Zhang, Mingming
Publisher / Repository:
Plos One
Date Published:
Journal Name:
PLOS ONE
Volume:
19
Issue:
11
ISSN:
1932-6203
Page Range / eLocation ID:
e0309654
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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