A global database of dissolved organic matter (DOM) measurements in coastal waters (CoastDOM v1)
Authors: Lønborg Christian , Carreira Cátia , Abril Gwenaël , Agustí Susana , Amaral Valentina , Andersson Agneta , Arístegui Javier , Bhadury Punyasloke , Bernardi Bif Mariana , Borges Alberto V. , Bouillon Steven , Ll. Calleja Maria , Cotovicz Jr. Luiz C. , Cozzi Stefano , Doval Maryló , Duarte Carlos M. , Eyre Bradley , Fichot Cédric G. , García-Martín E. Elena , Garzon-Garcia Alexandra , Giani Michele , Gonçalves-Araujo Rafael , Gruber Renee , A. Hansell Dennis , Hashihama Fuminori , He Ding , Holding Johnna M. , Hunter William R. , Ibánhez J. Severino P. , Ibello Valeria , Jiang Shan , Kim Guebuem , Klun Katja , Kowalczuk Piotr , Kubo Atsushi , Weng Lee Choon , Lopes Cláudia B. , Maggioni Federica , Magni Paolo , Marrase Celia , Martin Patrick , McCallister S. Leigh , McCallum Roisin , Medeiros Patricia M. , Morán Xosé Anxelu G. , Muller-Karger Frank , Myers-Pigg Allison , Norli Marit , Oakes Joanne M. , Osterholz Helena , Park Hyekyung , Lund Paulsen Maria , Rosentreter Judith A. , Rueda-Roa Digna , Santinelli Chiara , Shen Yuan , Teira Eva , Tinta Tinkara , Uher Guenther , Wakita Masahide , Ward Nicholas , Watanabe Kenta , Xin Yu , Yamashita Youhei , Yang Liyang , Yeo Jacob , Yuan Huamao , Zheng Qiang , Álvarez-Salgado Xosé Antón 
Published: September 2023

Abstract. The measurements of dissolved organic carbon (DOC), nitrogen (DON), and phosphorus (DOP) are used to characterize the dissolved organic matter (DOM) pool and are important components of biogeochemical cycling in the coastal ocean. Here, we present the first edition of a global database (CoastDOM v1; available at https://figshare.com/s/512289eb43c4f8e8eaef) compiling previously published and unpublished measurements of DOC, DON, and DOP collected in coastal waters. These data are complemented by hydrographic data such as temperature and salinity and, to the extent possible, other biogeochemical variables (e.g., Chlorophyll-a, inorganic nutrients) and the inorganic carbon system (e.g., dissolved inorganic carbon and total alkalinity). Overall, CoastDOM v1 includes observations from all continents however, most data were collected in the Northern Hemisphere, with a clear gap in coastal water DOM measurements from the Southern Hemisphere. The data included were collected from 1978 to 2022 and consist of 62339 data points for DOC, 20360 for DON and 13440 for DOP. The number of measurements decreases progressively in the sequence DOC > DON > DOP, reflecting both differences in the maturity of the analytical methods and the greater focus on carbon cycling by the aquatic science community. The global database shows that the average DOC concentration in coastal waters (average (standard deviation; SD): 182 (314) µmol C L−1; median: 103 µmol C L−1), is 13-fold greater than the average coastal DON concentrations (average (SD): 13.6 (30.4) µmol N L−1; median: 8.0 µmol N L−1), which was itself 39-fold greater than the average coastal DOP concentrations (average (SD): 0.34 ± 1.11 µmol P L−1; median: 0.18 µmol P L−1). This dataset will be useful to identify global spatial and temporal patterns in DOM and to facilitate reuse of DOC, DON and DOP data in studies aimed at better characterising local biogeochemical processes, closing nutrient budgets, estimating carbon, nitrogen and phosphorous pools, as well as identifying a baseline for modelling future changes in coastal waters.