A substantial amount of the atmospheric carbon taken up on land through photosynthesis and chemical weathering is transported laterally along the aquatic continuum from upland terrestrial ecosystems to the ocean. So far, global carbon budget estimates have implicitly assumed that the transformation and lateral transport of carbon along this aquatic continuum has remained unchanged since pre-industrial times. A synthesis of published work reveals the magnitude of present-day lateral carbon fluxes from land to ocean, and the extent to which human activities have altered these fluxes. We show that anthropogenic perturbation may have increased the flux of carbon to inland waters by as much as 1.0 Pg C yr -1 since pre-industrial times, mainly owing to enhanced carbon export from soils. Most of this additional carbon input to upstream rivers is either emitted back to the atmosphere as carbon dioxide (∼0.4 Pg C yr -1) or sequestered in sediments (∼0.5 Pg C yr -1) along the continuum of freshwater bodies, estuaries and coastal waters, leaving only a perturbation carbon input of ∼0.1 Pg C yr -1 to the open ocean. According to our analysis, terrestrial ecosystems store ∼0.9 Pg C yr -1 at present, which is in agreement with results from forest inventories but significantly differs from the figure of 1.5 Pg C yr -1 previously estimated when ignoring changes in lateral carbon fluxes. We suggest that carbon fluxes along the land-ocean aquatic continuum need to be included in global carbon dioxide budgets.
Department of Earth and Environmental Sciences, CP160/02, Université Libre de Bruxelles, 1050 Bruxelles, Belgium; College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, United Kingdom; Laboratoire des Sciences du Climat et l'Environnement, 91190 Gif-sur-Yvette, France; Department of Oceanography, School of Ocean and Earth Science and Technology, University of Hawai'i at Mãnoa, Honolulu, HI 96822, United States; Department of Environmental Sciences, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, 8092 Zurich, Switzerland; Departement Biologie, Universiteit Antwerpen, 2160 Wilrijk, Belgium; Institute for Biogeochemistry and Marine Chemistry, KlimaCampus, D-20146 Hamburg, Germany; Scripps Institution of Oceanography, University of California San Diego, San Diego, CA 92093-0202, United States; School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, United Kingdom; Department of Marine Sciences, University of North Carolina, Chapel Hill, NC 27599, United States; University of Liège, Chemical Oceanography Unit, Institut de Physique (B5), B-4000 Liège, Belgium; GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Wischhofstraße 1-3, 24148 Kiel, Germany; Department of Geography, University of Exeter, Exeter EX4 4RJ, United Kingdom; Géosciences Environnement Toulouse, Centre National de la Recherche Scientifique, Université Toulouse III, 31400 Toulouse, France; Geophysical Institute, University of Bergen, N-5007 Bergen, Norway; Bjerknes Centre for Climate Research, N-5007 Bergen, Norway; Uni Bjerknes Centre, Uni Research, N-5007 Bergen, Norway; Max Planck Institute for Meteorology, 20146 Hamburg, Germany; Climate and Environmental Physics, Physics Institute, University of Bern, Bern CH-3012, Switzerland; Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089, United States; Agroscope Research Station ART, Reckenholzstrasse 191, 8046 Zurich, Switzerland; Royal Netherlands Institute of Sea Research, 4401 NT Yerseke, Netherlands; Department of Analytical and Environmental Chemistry, Vrije Universiteit Brussel, 1050 Brussel, Belgium; Laboratoire de Physique Atmosphérique et Planétaire, Université de Liège, B-4000 Liège, Belgium; Yale School of Forestry and Environmental Studies, New Haven, CT 06511, United States; School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, United Kingdom; Department of Environmental Microbiology, Helmholtz Centre for Environmental Research, Leipzig 04318, Germany
Recommended Citation:
Regnier P.,Friedlingstein P.,Ciais P.,et al. Anthropogenic perturbation of the carbon fluxes from land to ocean[J]. Nature Geoscience,2013-01-01,6(8)