@article {2725,
	title = {Tropical peatland carbon storage linked to global latitudinal trends in peat recalcitrance},
	journal = {Nature Communications},
	volume = {9},
	year = {2018},
	month = {Jan-12-2018},
	abstract = {Peatlands represent large terrestrial carbon banks. Given that most peat accumulates in boreal regions, where low temperatures and water saturation preserve organic matter, the existence of peat in (sub)tropical regions remains enigmatic. Here we examined peat and plant chemistry across a latitudinal transect from the Arctic to the tropics. Near-surface low-latitude peat has lower carbohydrate and greater aromatic content than near-surface high-latitude peat, creating a reduced oxidation state and resulting recalcitrance. This recalcitrance allows peat to persist in the (sub)tropics despite warm temperatures. Because we observed similar declines in carbohydrate content with depth in high-latitude peat, our data explain recent field-scale deep peat warming experiments in which catotelm (deeper) peat remained stable despite temperature increases up to 9 {\textdegree}C. We suggest that high-latitude deep peat reservoirs may be stabilized in the face of climate change by their ultimately lower carbohydrate and higher aromatic composition, similar to tropical peats.},
	doi = {10.1038/s41467-018-06050-2},
	url = {http://www.nature.com/articles/s41467-018-06050-2},
	author = {Hodgkins, Suzanne B. and Richardson, Curtis J. and Dommain, Ren{\'e} and Wang, Hongjun and Glaser, Paul H. and Verbeke, Brittany and Winkler, B. Rose and Cobb, Alexander R. and Rich, Virginia I. and Missilmani, Malak and Flanagan, Neal and Ho, Mengchi and Hoyt, Alison M. and Harvey, Charles F. and Vining, S. Rose and Hough, Moira A. and Moore, Tim R. and Richard, Pierre J. H. and De La Cruz, Florentino B. and Toufaily, Joumana and Hamdan, Rasha and Cooper, William T. and Chanton, Jeffrey P.}
}
@article { ISI:000337285500012,
	title = {Organic matter transformation in the peat column at Marcell Experimental Forest: Humification and vertical stratification},
	journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
	volume = {119},
	number = {{4}},
	year = {2014},
	month = {APR 28},
	pages = {661-675},
	type = {Article},
	abstract = {We characterized peat decomposition at the Marcell Experimental Forest (MEF), Minnesota, USA, to a depth of 2m to ascertain the underlying chemical changes using Fourier transform infrared (FT IR) and C-13 nuclear magnetic resonance (NMR) spectroscopy) and related these changes to decomposition proxies C:N ratio, C-13 and N-15, bulk density, and water content. FT IR determined that peat humification increased rapidly between 30 and 75cm, indicating a highly reactive intermediate-depth zone consistent with changes in C:N ratio, C-13 and N-15, bulk density, and water content. Peat decomposition at the MEF, especially in the intermediate-depth zone, is mainly characterized by preferential utilization of O-alkyl-C, carboxyl-C, and other oxygenated functionalities with a concomitant increase in the abundance of alkyl- and nitrogen-containing compounds. Below 75cm, less change was observed but aromatic functionalities and lignin accumulated with depth. Significant correlations with humification indices, identified by FT IR spectroscopy, were found for C:N ratios. Incubation studies at 22 degrees C revealed the highest methane production rates, greatest CH4:CO2 production ratios, and significant O-alkyl-C utilization within this 30 and 75cm zone. Oxygen-containing functionalities, especially O-alkyl-C, appear to serve as excellent proxies for soil decomposition rate and should be a sensitive indicator of the response of the solid phase peat to increased temperatures caused by climate change and the field study manipulations that are planned to occur at this site. Radiocarbon signatures of microbial respiration products in deeper pore waters at the MEF resembled the signatures of more modern dissolved organic carbon rather than solid phase peat, indicating that recently photosynthesized organic matter fueled the bulk of subsurface microbial respiration. These results indicate that carbon cycling at depth at the MEF is not isolated from surface processes.},
	keywords = {FT-IR spectroscopy, humification, NMR spectroscopy, organic matter, peatlands, vertical stratification},
	issn = {2169-8953},
	doi = {10.1002/2013JG002492},
	author = {Tfaily, Malak M. and Cooper, William T. and Kostka, Joel E. and Chanton, Patrick R. and Schadt, Christopher W. and Hanson, Paul J. and Iversen, Colleen M. and Chanton, Jeffrey P.}
}
@article {2482,
	title = {Surface production fuels deep heterotrophic respiration in northern peatlands},
	journal = {Global Biogeochemical Cycles},
	volume = {27},
	year = {2013},
	month = {Jan-12-2013},
	pages = {1163 - 1174},
	abstract = {[1] Multiple analyses of dissolved organic carbon (DOC) from pore waters were conducted to define the processes that govern carbon balance in peatlands: (1) source, reactivity, and transport of DOC with respect to vegetation, peat, and age of carbon substrate, (2) reactivity of DOC with respect to molecular size, and (3) lability to photoxidation of surficial DOC. We found that surface organic production fuels heterotrophic respiration at depth in advection-dominated peatlands, especially in fens. Fen DOC was Δ14C enriched relative to the surrounding fen peat, and fen respiration products were similar to this enriched DOC indicating that DOC was the main microbial substrate. Bog DOC was more variable showing either enrichment in ∆14C at depth or ∆14C values that follow peat values. This variability in bogs is probably controlled by the relative importance of vertical transport of labile carbon substrates within the peat profile versus DOC production from bog peat. These results extended our set of observations to 10 years at one bog-fen pair and add two additional bog-fen pairs to our series of observations. Anaerobic incubations of peat, rinsed free of residual DOC, produced DOC and respiration products that were strikingly similar to the peat values in a bog and two fens. This result demonstrated conclusively that downward advection is the process responsible for the presence of modern DOC found at depth in the peat column. Fen DOC has lower C/N values and up to twice as much LMW (<1 kDa) DOC as bogs due to differences in organic inputs and greater microbial processing. Fluorescence irradiation experiments showed that fen DOC is more photolabile than bog DOC.},
	doi = {10.1002/2013GB004677},
	url = {http://doi.wiley.com/10.1002/2013GB004677https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002\%2F2013GB004677},
	author = {Elizabeth Corbett, J. and Burdige, David J. and Tfaily, Malak M. and Dial, Angela R. and Cooper, William T. and Glaser, Paul H. and Chanton, Jeffrey P.}
}
