Global Biogeochemical Cycles 28, 1343–1357
This paper uses a budget approach to compile information on excess reactive nitrogen (Nr) flows for Canada. Canada is a net receptor of Nr air pollution from the United States, receiving approximately 20% of the Nr leaving the U.S. airshed. Overall, terrestrial natural ecosystems as well as the atmosphere were found to be in balance between Nr inputs and outputs when all N reactive and nonreactive fluxes are included. However, when only reactive forms are considered, almost 50% of N entering the Canadian atmosphere is assumed to be lost to the oceans or to unmeasured dry deposition. Data suggest that denitrification in soils and aquatic systems is larger than what models predict.
This volume compiles individual papers on nitrogen deposition globally. The contributions focus on better quantification of atmospheric deposition, development and application of critical loads methodologies, look at the assessment of impacts on biodiversity, the consequences for ecosystem services, and include approaches to developing environmental policies to manage the threats of nitrogen deposition. Progress made clearly points out an obvious lack of information on impacts outside Europe and North America, and also regarding above- and below-ground fauna. The wealth of information on nitrogen effects on floral biodiversity clearly is helpful to the work under the Convention on Biological Diversity, specifically the Aichi biodiversity target 8 that aims to abate nutrient deposition detrimental to biodiversity.
Current Opinion in Environmental Sustainability, Vol. 9-10, October 2014, pp. 90-104The carbon to nitrogen response of forest ecosystems depends on the possible occurrence of nitrogen limitation versus possible co-limitations by other drivers, such as low temperature or availability of phosphorus. A combination of nitrogen retention estimates and stoichiometric scaling is used to illustrate the most likely carbon–nitrogen responses for needle-leaved and broadleaved forests to atmospheric nitrogen deposition.
Plant and Soil, July 2014, Volume 380, Issue 1-2, pp 1-45
Results from monitoring studies, both at a European wide scale and related national studies, are presented in terms of measured trends and geographic variation in N and S deposition and O3 concentrations/exposure, followed by results on effects of elevated N and S inputs and/or O3 exposure and/or climate on (i) Nutrient status, (ii) Forest health, (iii) Forest growth and (iv) Species diversity of the ground vegetation.
Nature Climate Change 4, 425-426 (2014).
Global carbon budgets indicate that approximately 27% of anthropogenic CO2 emissions are stored in terrestrial ecosystems with a similar percentage stored in the oceans. Of the terrestrial ecosystems, forests are by far the most important carbon sink, due to the long storage time of carbon in stem wood. Analysis of data from 92 forested sites across the globe indicates that nutrient availability is the dominant driver of carbon retention in forests.