Effects of atmospheric nitrogen deposition and climate on nitrogen export from unmanaged watersheds: a data synthesis

Templer Pamela H. 1, Harrison Jamie L. 1,2, Pilotto Francesca 3, Flores-Díaz Andri 4, Haase Peter 5,6, McDowell William H. 7, Sharif Rahat 8, Shibata Hideaki 9, Blankman David 10, Avila Anna 11, Baatar Undrakh-Od 12, Bogena Heye Reemt 13, Bourgeois Ilann 14, Campbell John 15, Dirnböck Thomas 16, Dodds Walter K. 17, Hauken Marit 18, Kokorite Ilga 19, Lajtha Kate 20, Lai Iling L. 21, Laudon Hjalmar 22, Lin Teng-Chiu 23, Lins Silvia Rafaela M. 24, Meesenburg Henning 25, Pinho Pedro 26, Robison Andrew 7, Rogora Michela 27, Scheler Birte 25, Schleppi Patrick 28, Sommaruga Ruben 29, Staszewski Tomasz 30, Taka Maija 31

1 Department of Biology, 5 Cummington Mall., Boston University, Boston, MA 02215, USA
2 Lamont-Doherty Earth Observatory of Columbia University, 306C Oceanography, 61 Route 9W, 17 Palisades, NY 10964, USA 18
3 Environmental Archaeology Lab, Department of Historical, Philosophical and Religious studies, 19 Umeå University, Umeå, Sweden 20
4 Transdisciplinary Center for Sustainability, Universidad Iberoamericana, Ciudad de México- 21 Tijuana. Prol. Paseo de la Reforma 880, Lomas de Santa Fe, Mexico City 01219, Mex. 22
5 Department of River Ecology and Conservation, Senckenberg Research Institute and Natural 23 History Museum Frankfurt, Gelnhausen, Germany 24
6 Faculty of Biology, University of Duisburg-Essen, Essen, Germany 25
7 Department of Natural Resources and the Environment, University of New Hampshire, Durham, 26 NH, 03824 27
8 Department of Environmental Science and Technology, University of Maryland - College Park, 28 Maryland, USA 29
9 Field Science Center for Northern Biosphere, Hokkaido University, Sapporo, Japan 30
10 ILTER Information Management Committee, Jerusalem, Israel 31
11 CREAF, Campus Universitat Autònoma de Barcelona, E08193, Bellaterra, Spain 32
12 Department of Botany and Biodiversity Research, Division of Conservation Biology, Vegetation 33 Ecology and Landscape Ecology, University of Vienna, Rennweg 14, 1030 Vienna Austria 34
13 Agrosphere Institute (IBG-3), Forschungszentrum Jülich, 52425 Jülich, Germany 35
14 Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, 36 Boulder, CO, USA and NOAA Chemical Science Laboratory, Boulder, CO, USA 37
15 US Forest Service, Northern Research Station, Durham, New Hampshire, USA 38
16 Environment Agency Austria, A-1090 Vienna, Austria 39
17 Division of Biology, Kansas State University, Manhattan, Kansas, USA 40
18 NIBIO, Norwegian Institute of Bioeconomy Research, Ås, Norway 41
19 Institute of Biology, University of Latvia, Jelgavas iela 1, Riga, LV-1004, Latvia and Latvian 42 Environment, Geology and Meteorology Center, Maskavas iela 165, LV-1019, Riga, Latvia 43
20 Department of Crop and Soil Sciences, Oregon State University, Corvallis OR, USA 44
21 Graduate Institute of Bioresources, National Pingtung University of Science and Technology, 1 45 Shuefu Rd, Neipu, Pingtung 912, Taiwan 46
22 Dept. Forest Ecology and Management, Swedish University of Agricultural Sciences, 901 83 47 Umeå, Sweden 48
23 Department of Life Science, National Taiwan Normal University, Taipei, Taiwan 49
24 Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, Brazil. 50
25 Northwest German Forest Research Institute, Grätzelstr. 2, 37079 Göttingen, Germany 51
26 Centre for Ecology, Evolution and Environmental Changes, Universidade de Lisboa, Lisbon, 52 Portugal 53
27 CNR Water Research Institute, L.go Tonolli 50, I 28922 Verbania Pallanza, Italy 54
28 Swiss Federal Institute for Forest, Snow and Landscape Research, Zürcherstr. 111, CH-8903 55 Birmensdorf, Switzerland 56
29 Department of Ecology, University of Innsbruck, 6020 Innsbruck, Austria 57
30 Integrated Monitoring Department, Institute for Ecology of Industrial Area, Katowice, Poland 58
31 Water and Environmental Engineering Research Group, Aalto University, P.O. Box 15200, FI- 59 00076 Aalto, Espoo, Finland

Biogeochem. (2022) (in press)

DOI: 10.1007/s10533-022-00951-7


Many studies have evaluated how changes in atmospheric nitrogen (N) inputs and climate affect stream N concentrations and fluxes, but we are unaware of any study synthesizing data from sites around the globe. To fill this gap and to identify variables controlling stream N concentrations and fluxes, and to determine how these patterns change over time, we synthesized 20 time series ranging from 5 to 51 years of data collected from ecosystems across Europe, North America, and East Asia and across four climate types (tropical, temperate, Mediterranean, and boreal) using the International Long-Term Ecological Research Network. We hypothesized that sites with greater rates of atmospheric deposition and higher annual temperatures have greater stream N concentrations and fluxes. However, with rates of atmospheric deposition declining in many regions of the globe, we expected climate, more than atmospheric deposition, to drive stream N concentrations and fluxes. There were significant positive relationships between (1) rates of annual precipitation and stream ammonium flux, (2) throughfall ammonium deposition flux and both stream nitrate concentrations and total inorganic N concentrations, and (3) bulk nitrate deposition flux and both stream nitrate and total inorganic N concentrations. Stream nitrate fluxes were significantly positively related to annual rates of precipitation, as well as throughfall, wet, and bulk rates of nitrogen deposition fluxes, but were not related to mean annual temperature. Our results show that while rates of atmospheric N deposition are declining, deposition is still a strong driver of biogeochemical cycling of N export from unmanaged watersheds around the globe.

Keywords: bulk deposition, data synthesis, LTER, pollution, throughfall, watershed, water quality