A reactive nitrogen budget for forest land and wetlands in Latvia and Estonia

ABSTRACT

Human intervention in global nitrogen cycling has led to excess reactive nitrogen (Nr) flows to the environment, impacting terrestrial ecosystems as well as the quality of the atmosphere and waterbodies. This paper presents the results of a study that quantified and compared the main flows of Nr through forest land and wetlands in Latvia and Estonia using substance flow analysis approach based on data from statistics, research results, reports, monitoring programmes, data bases and expert estimations. Input and output flows to and from the forest land and wetlands both in Latvia and Estonia are well balanced, with a trend to be a Nr sink (+1.2 kT N yr⁻¹) for Latvia and a Nr source (−6.5 kT N yr⁻¹) for Estonia. Major input flow to the studied pools in Estonia is a soil nitrogen stock used for forest growth, while in Latvia, it is atmospheric deposition and biological fixation. Major output flow of Nr in both countries occurs via wood and peat for industrial uses. Emissions of Nr to the atmosphere and hydrosphere from forest land and wetlands are significantly lower compared to human-related emissions such as industries, energy production, agriculture, human settlements, and transport.

KEYWORDS:

• Reactive nitrogen
• reactive nitrogen budget
• forest land
• wetlands
• Latvia
• Estonia

Acknowledgments

This work was supported by the Interreg V-A Estonia-Latvia (Est-Lat 20) programme’s project “Integrated Nitrogen Management System for the Gulf of Riga (GURINIMAS)” (research) and the integrated project “Implementation of River Basin Management Plans of Latvia towards good surface water status” (LIFE GOODWATER IP, LIFE18 IPE/LV/000014) financed by the LIFE Programme of the European Union and Administration of Latvian Environmental Protection Fund (manuscript preparation and publication costs). The information reflects only the LIFE GOODWATER IP project beneficiaries’ view and the European Commission’s Executive Agency for Small and Medium-sized Enterprises is not responsible for any use that may be made of the information contained therein.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Interreg V-A Estonia-Latvia (Est-Lat 20) programme’s project “Integrated Nitrogen Management System for the Gulf of Riga (GURINIMAS)” (research) and the integrated project “Implementation of River Basin Management Plans of Latvia towards good surface water status” (LIFE GOODWATER IP, LIFE18 IPE/LV/000014) financed by the LIFE Programme of the European Union and Administration of Latvian Environmental Protection Fund (manuscript preparation and publication costs).