Tropical peatland carbon storage linked to global latitudinal trends in peat recalcitrance

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 degrees 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.US Department of Energy Office of Biological and Environmental Research under the Terrestrial Ecosystem Sciences program [DE-SC0012272]; NASA Interdisciplinary Studies in Earth Science program [NNX17AK10G]; US Department of Energy Office of Biological and Environmental Research under the Genomic Science program [DE-SC0016440, DE-SC0004632, DE-SC0010580]; Geo. X, the Research Network for Geosciences in Berlin and Potsdam; US Department of Energy, Office of Science, Office of Biological and Environmental Research [DE-SC0012088]; NSF [0628647]; Natural Sciences and Engineering Research Council of Canada; National Research Foundation Singapore through the Singapore-MIT Alliance for Research and Technology's Center for Environmental Sensing and Modeling interdisciplinary research program; USA National Science Foundation [1114155, 1114161]; NASA LaRC POWER ProjectOpen access journal.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu