title: High potential for weathering and climate effects of non-vascular vegetation in the Late Ordovician.
abstract: It has been hypothesized that predecessors of today's bryophytes significantly increased global chemical weathering in the Late Ordovician, thus reducing atmospheric CO2 concentration and contributing to climate cooling and an interval of glaciations. Studies that try to quantify the enhancement of weathering by non-vascular vegetation, however, are usually limited to small areas and low numbers of species, which hampers extrapolating to the global scale and to past climatic conditions. Here we present a spatially explicit modelling approach to simulate global weathering by non-vascular vegetation in the Late Ordovician. We estimate a potential global weathering flux of 2.8 (km(3) rock) yr(-1), defined here as volume of primary minerals affected by chemical transformation. This is around three times larger than today's global chemical weathering flux. Moreover, we find that simulated weathering is highly sensitive to atmospheric CO2 concentration. This implies a strong negative feedback between weathering by non-vascular vegetation and Ordovician climate.
authors.affiliation: Department of Environmental Science and Analytical Chemistry (ACES), Stockholm University, 10691 Stockholm, Sweden.|Bolin Centre for Climate Research, Stockholm University, 10691 Stockholm, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Porada
authors.affiliation: Earth System Science Group, College of Life and Environmental Sciences, University of Exeter, Laver Building (Level 7), North Park Road, Exeter EX4 4QE, UK.
authors.forename: T M
authors.initials: TM
authors.lastname: Lenton
authors.affiliation: Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France.
authors.forename: A
authors.identifier: http://orcid.org/0000-0003-2328-351X
authors.initials: A
authors.lastname: Pohl
authors.affiliation: Max Planck Institute for Chemistry, PO Box 3060, 55020 Mainz, Germany.
authors.forename: B
authors.identifier: http://orcid.org/0000-0002-5453-3967
authors.initials: B
authors.lastname: Weber
authors.affiliation: Department of Environment, Earth and Ecosystems, The Open University, Milton Keynes, Buckinghamshire MK7 6AA, UK.
authors.forename: L
authors.initials: L
authors.lastname: Mander
authors.affiliation: Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France.|Aix-Marseille Université, CNRS, IRD, CEREGE UM34, 13545 Aix en Provence, France.
authors.forename: Y
authors.initials: Y
authors.lastname: Donnadieu
authors.affiliation: Department of Environmental Science and Analytical Chemistry (ACES), Stockholm University, 10691 Stockholm, Sweden.|Bolin Centre for Climate Research, Stockholm University, 10691 Stockholm, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Beer
authors.affiliation: Max Planck Institute for Chemistry, PO Box 3060, 55020 Mainz, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Pöschl
authors.affiliation: Max Planck Institute for Biogeochemistry, PO Box 10 01 64, 07701 Jena, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Kleidon