Greenhouse gas dynamics in lakes receiving atmospheric nitrogen deposition

Abstract

[1] 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 −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.Citation: McCrackin, M. L., and J. J. Elser (2011), Greenhouse gas dynamics in lakes receiving atmospheric nitrogen deposition, Global Biogeochem. Cycles, 25, GB4005,

The interactive effects of excess reactive nitrogen and climate change on aquatic ecosystems and water resources of the United States

“…This value is similar to the 0.037 Tg N year -1 (6 % of US freshwater N 2 O production, Fig. 2b) calculated by us using the approach of McCrackin and Elser (2011) for estimating N 2 O production and the N loading rates provided by Harrison et al (2009). Liu et al (2011) found that deep waters of reservoirs used for hydroelectric generation were supersaturated with N 2 O year-round, as was water directly downstream, suggesting that deep waters released for hydropower are additional sources of N 2 O produced by reservoirs.…”

“…Figure produced with methods from Harrison et al (2009) ozone depletion, a better quantification of sources and processes is needed (Verhoeven et al 2006;Beaulieu et al 2011;McCrackin and Elser 2011;Pinder et al 2012). Although N 2 O emissions are estimated to be B1 % of the N denitrified in aquatic systems, this amount is important with respect to global N 2 O budgets (Beaulieu et al 2011).…”

Greenhouse gas metabolism in Nordic boreal lakes

“…In boreal, pristine lakes, terrestrially derived DOM is the key source of TOC, as well as of P and N. TOC will decrease primary production owing to increased light attenuation (Thrane et al 2014), but increase the likelihood of epilimnetic anoxia and thus support methanogenic activity (Bastviken et al 2004a), hence the net effect of browning on CH 4 is likely positive. For N 2 O, it is first and foremost high (or elevated) levels of N inputs that will promote increased emissions, and given the widespread impacts of increased N deposition on lake ecosystems (Elser et al 2009;McCrackin and Elser 2011), the coupling of climate, TOC and N deposition for GHG-emissions is a topic that warrants further attention. Advancing our understanding of lake browning in terms of global warming (GWP, i.e.…”

Weak response of greenhouse gas emissions to whole lake N enrichment

“…In unproductive boreal lakes, atmospheric N deposition has enhanced phytoplankton growth due to the fact that phytoplankton is often N limited in these systems (Bergström and Jansson ; Elser et al ; Lepori and Keck ). Additional N supply can also be expected to affect cycling and emissions of greenhouse gases such as carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O) (McCrackin and Elser ; Kortelainen et al ; Yang et al ). Such effects are poorly understood but urgently need to be revealed especially for boreal regions, given the ongoing and predicted regional future increases in N loads under climate warming (Hole and Engardt ), more intense local forestry activities (Laudon et al ), and atmospheric deposition (Galloway et al ).…”

“…In‐lake greenhouse gas dynamics have been shown to respond to N or N + P enrichment by different types of studies with a wide range of spatiotemporal scales. Studies comprise of sediment incubations (Liikanen et al ; McCrackin and Elser ), mesocosm‐ (Peixoto et al ; Davidson et al ) and whole‐lake experiments (Kling et al ; Findlay et al ; Carpenter et al ), and observations over time and space across gradients in nutrient inputs (Marotta et al ; Gu et al ; McCrackin and Elser ; Yang et al ). These studies showed that N addition often increased N 2 O accumulation in lakes but induced variable effects on CO 2 and CH 4 dynamics.…”