Funder: The Nature Conservancy through the Bezos Earth Fund and other donor supportFunder: Nelson Mandela UniversityFunder: State Research Agency of Spain (AEI; CGL2007-64915), the Mancomunidad de los Canales del Taibilla (MCT), and the Science and Technology Agency of the Murcia Region (Seneca Foundation; 00593/PI/04 & 08739/PI/08).Funder: Scottish Government and UK Natural Environment Research Council C-SIDE project (grant NE/R010846/1)Funder: COOLSTYLE/CARBOSTORE projectFunder: New Zealand Ministry for Business, Innovation and Employment Contract #C01X2109Funder: Portuguese national funds from FCT - Foundation for Science and Technology through projects UIDB/04326/2020, UIDP/04326/2020, LA/P/0101/2020, and 2020.03825.CEECINDFunder: German Research Foundation (DFG project number: GI 171/25-1)Funder: State Research Agency of Spain (AEI; CGL2007-64915), the Mancomunidad de los Canales del Taibilla (MCT), the Science and Technology Agency of the Murcia Region (Seneca Foundation; 00593/PI/04 & 08739/PI/08), and a Ramón y Cajal contract from the Spanish Ministry of Science and Innovation (RYC2020-029322-I)Funder: Velux foundation (#28421, Blå Skove – Havets Skove som kulstofdræn)Funder: LIFE ADAPTA BLUES project Ref. LIFE18 CCA/ES/001160Funder: LIFE ADAPTA BLUES project Ref. LIFE18 CCA/ES/001160, support of national funds through Fundação para a Ciência e Tecnologia, I.P. (FCT), under the projects UIDB/04292/2020, UIDP/04292/2020, granted to MARE, and LA/P/0069/2020, granted to the Associate Laboratory ARNETFunder: Financial support provided by the Welsh Government and Higher Education Funding Council for Wales through the Sêr Cymru National Research Network for Low Carbon, Energy and Environment; as well as the Spanish Ministry of Science and Innovation (project PID2020-113745RB-I00) and FEDERFunder: South African Department of Science and Innovation (DSI)—National Research Foundation (NRF) Research Chair in Shallow Water Ecosystems (UID: 84375), and the Nelson Mandela UniversityFunder: I+D+i projects RYC2019-027073-I and PIE HOLOCENO 20213AT014 funded by MCIN/AEI/10.13039/501100011033 and FEDERFunder: Funding support from the Scottish Government and UK Natural Environment Research Council C-SIDE project (grant NE/R010846/1)Funder: Xunta de Galicia (GRC project IN607A 2021-06)Funder: U.S. Army Engineering, Research and Development Center (ACTIONS project, W912HZ2020070)Tidal marshes store large amounts of organic carbon in their soils. Field data quantifying soil organic carbon (SOC) stocks provide an important resource for researchers, natural resource managers, and policy-makers working towards the protection, restoration, and valuation of these ecosystems. We collated a global dataset of tidal marsh soil organic carbon (MarSOC) from 99 studies that includes location, soil depth, site name, dry bulk density, SOC, and/or soil organic matter (SOM). The MarSOC dataset includes 17,454 data points from 2,329 unique locations, and 29 countries. We generated a general transfer function for the conversion of SOM to SOC. Using this data we estimated a median (± median absolute deviation) value of 79.2 ± 38.1 Mg SOC ha-1 in the top 30 cm and 231 ± 134 Mg SOC ha-1 in the top 1 m of tidal marsh soils globally. This data can serve as a basis for future work, and may contribute to incorporation of tidal marsh ecosystems into climate change mitigation and adaptation strategies and policies
