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Nitrous oxide and methane emissions from cryptogamic covers
Author(s) -
Lenhart Katharina,
Weber Bettina,
Elbert Wolfgang,
Steinkamp Jörg,
Clough Tim,
Crutzen Paul,
Pöschl Ulrich,
Keppler Frank
Publication year - 2015
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.12995
Subject(s) - nitrous oxide , environmental science , methane , greenhouse gas , environmental chemistry , lichen , nitrogen , carbon dioxide , deposition (geology) , atmospheric sciences , atmosphere (unit) , chemistry , ecology , biology , meteorology , geology , paleontology , physics , organic chemistry , sediment
Abstract Cryptogamic covers, which comprise some of the oldest forms of terrestrial life on Earth (Lenton & Huntingford, [Lenton TM, 2003]), have recently been found to fix large amounts of nitrogen and carbon dioxide from the atmosphere (Elbert et al ., [Elbert W, 2012]). Here we show that they are also greenhouse gas sources with large nitrous oxide (N 2 O) and small methane ( CH 4 ) emissions. Whilst N 2 O emission rates varied with temperature, humidity, and N deposition, an almost constant ratio with respect to respiratory CO 2 emissions was observed for numerous lichens and bryophytes. We employed this ratio together with respiration data to calculate global and regional N 2 O emissions. If our laboratory measurements are typical for lichens and bryophytes living on ground and plant surfaces and scaled on a global basis, we estimate a N 2 O source strength of 0.32–0.59 Tg year −1 for the global N 2 O emissions from cryptogamic covers. Thus, our emission estimate might account for 4–9% of the global N 2 O budget from natural terrestrial sources. In a wide range of arid and forested regions, cryptogamic covers appear to be the dominant source of N 2 O. We suggest that greenhouse gas emissions associated with this source might increase in the course of global change due to higher temperatures and enhanced nitrogen deposition.