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Greenhouse gas dynamics in lakes receiving atmospheric nitrogen deposition
Author(s) -
McCrackin Michelle L.,
Elser James J.
Publication year - 2011
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2010gb003897
Subject(s) - nitrous oxide , deposition (geology) , greenhouse gas , environmental science , nitrogen , environmental chemistry , ecosystem , carbon dioxide , ozone , methane , surface water , atmosphere (unit) , terrestrial ecosystem , aquatic ecosystem , hydrology (agriculture) , atmospheric sciences , ecology , chemistry , environmental engineering , sediment , geology , biology , geotechnical engineering , organic chemistry , paleontology , physics , thermodynamics
Anthropogenic nitrogen (N) inputs have been found to influence emissions of greenhouse gases from a variety of ecosystems; however, the effects of N loading on greenhouse gas dynamics in lakes are not well documented. We measured concentrations of carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O) in 26 lakes in the Colorado Rocky Mountains (USA) receiving elevated (5 – 8 kg N ha −1 yr −1 ) or low (<2 kg N ha −1 y −1 ) levels of atmospheric N deposition. The mean CO 2 concentration in surface waters was 27 μ mol L −1 and did not differ between deposition regions. The CH 4 concentration was greater in low‐deposition lakes (167 nmol L −1 ) compared to high‐deposition lakes (48 nmol L −1 ), while the opposite was true for N 2 O. The concentration of N 2 O in surface water averaged 29 nmol L −1 in high‐deposition lakes compared to 22 nmol L −1 in low‐deposition lakes. Nitrous oxide is of particular interest because it is more potent than CO 2 as a greenhouse gas and because of its role in the destruction of stratospheric ozone. To understand the potential magnitude of lake N 2 O production related to atmospheric N deposition, we applied two published methodologies for determining emissions from aquatic ecosystems to available data sets. We estimated contemporary global N 2 O emissions from lakes to be 0.04 – 2 Tg N y −1 , increasing to 0.1 – 3.4 Tg N y −1 in 2050. The contemporary estimates represent 13–95% of emissions from rivers and estuaries, suggesting that further research is required to better quantify emission rates from lentic ecosystems.