Carbon-nitrogen interactions in European forests and semi-natural vegetation - Part 1: Fluxes and budgets of carbon, nitrogen and greenhouse gases from ecosystem monitoring and modelling
Artikel i vetenskaplig tidskrift, 2020
The impact of atmospheric reactive nitrogen (N-r) deposition on carbon (C) sequestration in soils and biomass of unfertilized, natural, semi-natural and forest ecosystems has been much debated. Many previous results of this dC/dN response were based on changes in carbon stocks from periodical soil and ecosystem inventories, associated with estimates of N-r deposition obtained from large-scale chemical transport models. This study and a companion paper (Flechard et al., 2020) strive to reduce uncertainties of N effects on C sequestration by linking multi-annual gross and net ecosystem productivity estimates from 40 eddy covariance flux towers across Europe to local measurement-based estimates of dry and wet N-r deposition from a dedicated collocated monitoring network. To identify possible ecological drivers and processes affecting the interplay between C and N-r inputs and losses, these data were also combined with in situ flux measurements of NO, N2O and CH4 fluxes; soil NO3- leaching sampling; and results of soil incubation experiments for N and greenhouse gas (GHG) emissions, as well as surveys of available data from online databases and from the literature, together with forest ecosystem (BAS-FOR) modelling. Multi-year averages of net ecosystem productivity (NEP) in forests ranged from -70 to 826 gCm(-2) yr(-1) at total wet + dry inorganic N-r deposition rates (N-dep) of 0.3 to 4.3 gNm(-2) yr(-1) and from -4 to 361 g Cm-2 yr(-1) at N-dep rates of 0.1 to 3.1 gNm(-2) yr(-1) in short semi-natural vegetation (moorlands, wetlands and unfertilized extensively managed grasslands). The GHG budgets of the forests were strongly dominated by CO2 exchange, while CH4 and N2O exchange comprised a larger proportion of the GHG balance in short semi-natural vegetation. Uncertainties in elemental budgets were much larger for nitrogen than carbon, especially at sites with elevated N-dep where N-r leaching losses were also very large, and compounded by the lack of reliable data on organic nitrogen and N-2 losses by denitrification. Nitrogen losses in the form of NO, N2O and especially NO3- were on average 27%(range 6 %-54 %) of N-dep at sites with N-dep < 1 gNm(-2) yr(-1) versus 65% (range 35 %-85 %) for N-dep > 3 gNm(-2) yr(-1). Such large levels of N-r loss likely indicate that different stages of N saturation occurred at a number of sites. The joint analysis of the C and N budgets provided further hints that N saturation could be detected in altered patterns of forest growth. Net ecosystem productivity increased with N-r deposition up to 2-2.5 gNm(-2) yr(-1), with large scatter associated with a wide range in carbon sequestration efficiency (CSE, defined as the NEP/GPP ratio). At elevated N-dep levels (> 2.5 gNm(-2) yr(-1)), where inorganic N-r losses were also increasingly large, NEP levelled off and then decreased. The apparent increase in NEP at low to intermediate N-dep levels was partly the result of geographical cross-correlations between N-dep and climate, indicating that the actual mean dC/dN response at individual sites was significantly lower than would be suggested by a simple, straightforward regression of NEP vs. N-dep.
Författare
Chris R. Flechard
Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (INRAE)
Andreas Ibrom
Danmarks Tekniske Universitet (DTU)
Ute M. Skiba
UK Centre For Ecology & Hydrology (UKCEH)
Wim de Vries
Wageningen University and Research
Marcel van Oijen
UK Centre For Ecology & Hydrology (UKCEH)
David R. Cameron
UK Centre For Ecology & Hydrology (UKCEH)
Nancy B. Dise
UK Centre For Ecology & Hydrology (UKCEH)
Janne F. J. Korhonen
Helsingin Yliopisto
Nina Buchmann
Eidgenössische Technische Hochschule Zürich (ETH)
Arnaud Legout
Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (INRAE)
David Simpson
Chalmers, Rymd-, geo- och miljövetenskap, Mikrovågs- och optisk fjärranalys
Maria J. Sanz
Universidad del Pais Vasco / Euskal Herriko Unibertsitatea
Marc Aubinet
Universite de Liège
Denis Loustau
Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (INRAE)
Leonardo Montagnani
Forest Service of Autonomous Province of Bolzano
Free University of Bozen-Bolzano
Johan Neirynck
Research Institute for Nature and Forest, Brussels
Ivan A. Janssens
Universiteit Antwerpen
Mari Pihlatie
Helsingin Yliopisto
Ralf Kiese
Karlsruher Institut für Technologie (KIT)
Jan Siemens
Justus-Liebig-Universität Gießen
Andre-Jean Francez
Université de Rennes 1
Juergen Augustin
Leibniz-Zentrum für Agrarlandschaftsforschung (ZALF)
Andrej Varlagin
Russian Academy of Sciences
Janusz Olejnik
Global Change Research Centre
Poznan University of Life Sciences
Radoslaw Juszczak
Poznan University of Life Sciences
Mika Aurela
Finnish Meteorological Institute
Daniel Berveiller
Université Paris-Sud
Bogdan H. Chojnicki
Poznan University of Life Sciences
Ulrich Dammgen
Johann Heinrich von Thünen-Institut Bundesforschungsinstitut für Ländliche Räume, Wald und Fischerei
Nicolas Delpierre
Université Paris-Sud
Vesna Djuricic
Meteorological and Hydrological Service
Julia Drewer
UK Centre For Ecology & Hydrology (UKCEH)
Eric Dufrene
Université Paris-Sud
Werner Eugster
Eidgenössische Technische Hochschule Zürich (ETH)
Yannick Fauvel
Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (INRAE)
David Fowler
UK Centre For Ecology & Hydrology (UKCEH)
Arnoud Frumau
Nederlandse Organisatie voor toegepast-natuurwetenschappelijk onderzoek (TNO)
Andre Granier
Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (INRAE)
Patrick Gross
Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (INRAE)
Yannick Hamon
Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (INRAE)
Carole Helfter
UK Centre For Ecology & Hydrology (UKCEH)
Arjan Hensen
Nederlandse Organisatie voor toegepast-natuurwetenschappelijk onderzoek (TNO)
Laszlo Horvath
Greengrass - Atmospheric Environment Expert Ltd. Fellowship
Barbara Kitzler
Federal Research and Training Centre for Forests, Natural Hazards and Landscape
Bart Kruijt
Wageningen University and Research
Werner L. Kutsch
Integrated Carbon Observation System (ICOS ERIC)
Raquel Lobo-do-Vale
Universidade de Lisboa
Annalea Lohila
Finnish Meteorological Institute
Helsingin Yliopisto
Bernard Longdoz
Gembloux Agro-Bio Tech
Marek
Czech Academy of Sciences
Giorgio Matteucci
Consiglio Nazionale delle Ricerche (CNR)
Marta Mitosinkova
Slovak Hydrometeorological Institute
Virginie Moreaux
Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (INRAE)
Université Grenoble Alpes
Albrecht Neftel
NRE
Jean-Marc Ourcival
Université de Montpellier
Kim Pilegaard
Danmarks Tekniske Universitet (DTU)
Gabriel Pita
Instituto Superior Tecnico
Francisco Sanz
Fundación CEAM
Jan K. Schjoerring
Köpenhamns universitet
Maria-Teresa Sebastia
Forest Science and Technology Centre of Catalonia (CTFC)
Universidad De Lleida
Y. Sim Tang
UK Centre For Ecology & Hydrology (UKCEH)
Hilde Uggerud
Norsk institutt for luftforskning (NILU)
Marek Urbaniak
Poznan University of Life Sciences
Netty van Dijk
UK Centre For Ecology & Hydrology (UKCEH)
Timo Vesala
Helsingin Yliopisto
Sonja Vidic
Meteorological and Hydrological Service
Caroline Vincke
Universite catholique de Louvain
Tamas Weidinger
Eötvös Loránd University (ELTE)
Sophie Zechmeister-Boltenstern
Universität für Bodenkultur
Klaus Butterbach-Bah
Karlsruher Institut für Technologie (KIT)
Eiko Nemitz
UK Centre For Ecology & Hydrology (UKCEH)
Mark A. Sutton
UK Centre For Ecology & Hydrology (UKCEH)
Biogeosciences
1726-4170 (ISSN) 1726-4189 (eISSN)
Vol. 17 6 1583-1620Ämneskategorier
Miljö- och naturvårdsvetenskap
Naturgeografi
Miljövetenskap
DOI
10.5194/bg-17-1583-2020