Soil carbon in the world's tidal marshes

Tania L Maxwell; Mark D Spalding; Daniel A Friess; Nicholas J Murray; Kerrylee Rogers; Andre S Rovai; Lindsey S Smart; Lukas Weilguny; Maria Fernanda Adame; Janine B Adams; William E N Austin; Margareth S Copertino; Grace M Cott; Micheli Duarte de Paula Costa; James R Holmquist; Cai J T Ladd; Catherine E Lovelock; Marvin Ludwig; Monica M Moritsch; Alejandro Navarro; Jacqueline L Raw; Ana-Carolina Ruiz-Fernández; Oscar Serrano; Craig Smeaton; Marijn Van de Broek; Lisamarie Windham-Myers; Emily Landis; Thomas A Worthington

doi:10.1038/s41467-024-54572-9

Soil carbon in the world's tidal marshes

Nat Commun. 2024 Nov 26;15(1):10265. doi: 10.1038/s41467-024-54572-9.

Authors

Tania L Maxwell^{1

2}, Mark D Spalding^{3

4}, Daniel A Friess⁵, Nicholas J Murray⁶, Kerrylee Rogers⁷, Andre S Rovai^{8

9}, Lindsey S Smart^{10

11}, Lukas Weilguny¹², Maria Fernanda Adame¹³, Janine B Adams^{14

15}, William E N Austin^{16

17}, Margareth S Copertino^{18

19}, Grace M Cott²⁰, Micheli Duarte de Paula Costa²¹, James R Holmquist²², Cai J T Ladd^{23

24}, Catherine E Lovelock²⁵, Marvin Ludwig²⁶, Monica M Moritsch²⁷, Alejandro Navarro⁶, Jacqueline L Raw^{15

28}, Ana-Carolina Ruiz-Fernández²⁹, Oscar Serrano³⁰, Craig Smeaton¹⁶, Marijn Van de Broek³¹, Lisamarie Windham-Myers³², Emily Landis¹⁰, Thomas A Worthington³³

Affiliations

¹ Conservation Science Group, Department of Zoology, University of Cambridge, Cambridge, UK. taniamaxwell7@gmail.com.
² Biodiversity, Ecology and Conservation Research Group, International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria. taniamaxwell7@gmail.com.
³ Conservation Science Group, Department of Zoology, University of Cambridge, Cambridge, UK.
⁴ The Nature Conservancy, Siena, Italy.
⁵ Department of Earth and Environmental Sciences, Tulane University, New Orleans, LA, USA.
⁶ College of Science and Engineering, James Cook University, Townsville, QLD, Australia.
⁷ Environmental Futures, School of Science, University of Wollongong, Wollongong, NSW, Australia.
⁸ U.S. Army Engineer Research and Development Center, Vicksburg, MS, USA.
⁹ Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA, USA.
¹⁰ The Nature Conservancy, Arlington, VA, USA.
¹¹ Department of Forestry and Environmental Resources, NC State University, Raleigh, NC, USA.
¹² European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, UK.
¹³ Australian Rivers Institute, Coastal and Marine Research Centre, Griffith University, Nathan, QLD, Australia.
¹⁴ Department of Botany, Nelson Mandela University, Gqeberha, South Africa.
¹⁵ Institute for Coastal and Marine Research, Nelson Mandela University, Gqeberha, South Africa.
¹⁶ School of Geography and Sustainable Development, University of St Andrews, St Andrews, UK.
¹⁷ Scottish Association of Marine Science, Oban, UK.
¹⁸ Federal University of Rio Grande (FURG), Rio Grande, Brazil.
¹⁹ Brazilian Network of Climate Change Studies-Rede CLIMA, Rio Grande, Brazil.
²⁰ School of Biology and Environmental Science, University College Dublin, Belfield, Ireland.
²¹ Deakin Marine Research and Innovation Centre, School of Life and Environmental Sciences, Deakin University, Warrnambool, VIC, Australia.
²² Smithsonian Environmental Research Center, Edgewater, MD, USA.
²³ Department of Geography, Swansea University, Swansea, UK.
²⁴ School of Ocean Sciences, Bangor University, Menai Bridge, UK.
²⁵ School of Environment, The University of Queensland, St Lucia, QLD, Australia.
²⁶ Institute of Landscape Ecology, University of Münster, Münster, Germany.
²⁷ University of California, Santa Cruz, Santa Cruz, CA, USA.
²⁸ Anthesis South Africa, Cape Town, South Africa.
²⁹ Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Unidad Académica Mazatlán, Mazatlán, Mexico.
³⁰ Centro de Estudios Avanzados de Blanes (CEAB), Blanes, Spain.
³¹ Swiss Federal Institute of Technology (ETH Zürich), Zürich, Switzerland.
³² California Delta Stewardship Council, Sacramento, CA, USA.
³³ Conservation Science Group, Department of Zoology, University of Cambridge, Cambridge, UK. taw52@cam.ac.uk.

Abstract

Tidal marshes are threatened coastal ecosystems known for their capacity to store large amounts of carbon in their water-logged soils. Accurate quantification and mapping of global tidal marshes soil organic carbon (SOC) stocks is of considerable value to conservation efforts. Here, we used training data from 3710 unique locations, landscape-level environmental drivers and a global tidal marsh extent map to produce a global, spatially explicit map of SOC storage in tidal marshes at 30 m resolution. Here we show the total global SOC stock to 1 m to be 1.44 Pg C, with a third of this value stored in the United States of America. On average, SOC in tidal marshes' 0-30 and 30-100 cm soil layers are estimated at 83.1 Mg C ha^-1 (average predicted error 44.8 Mg C ha^-1) and 185.3 Mg C ha^-1 (average predicted error 105.7 Mg C ha^-1), respectively.