/* DATA DESCRIPTION: Citation: Gledhill, Martha; Liu, Fengjie (2026): Present day iron speciation in the surface ocean, Version 2 [dataset]. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.993556 (DOI registration in progress) Abstract: The main component of this data set comprises calculated inorganic iron concentrations (Fe' = sum of iron hydroxide species). Inorganic iron is the most bioavailable chemical form of Fe in the ocean. Concentrations of Fe' were calculated according to two models, which we refer to as the discrete ligand model and the continuous binding site model. The discrete ligand model, which is currently applied to calculate Fe speciation in global biogeochemical models, combines dissolved Fe concentrations, conditional stability constants and ligand concentrations to obtain inorganic iron, whilst the continuous distribution model uses the NICA-Donnan model to obtain Fe'. Other version: Gledhill, Martha; Liu, Fengjie; Zhang, Qiong; Browning, Thomas J; Twining, Ben S; Buck, Kristen N; Kwiatkowski, Lester; Bowler, Chris; Achterberg, Eric Pieter (2024): Present day and end of century (2100) iron speciation in the surface ocean [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.966487 Project(s): Development of a consistent thermodynamic model of trace element - organic matter interactions in the Ocean (GL807/2-1) Funding: European Commission (EC) (URI: https://commission.europa.eu/index_en), grant/award no. 891418: Marie Curie: Iron speciation in the microenvironment surrounding phytoplankton cells and the consequences for Fe bioavailability Natural Environment Research Council (NERC) (URI: http://www.nerc.ac.uk/), grant/award no. NE/V01451X/1: Controls on iron availability to marine phytoplankton (URI: https://gtr.ukri.org/projects?ref=NE/V01451X/1) Parameter(s): Description (Description) * PI: Gledhill, Martha (https://orcid.org/0000-0003-3859-2112, mgledhill@geomar.de) Binary Object (Binary) * PI: Gledhill, Martha (https://orcid.org/0000-0003-3859-2112, mgledhill@geomar.de) Binary Object (File Size) [Bytes] (Binary (Size)) * PI: Gledhill, Martha (https://orcid.org/0000-0003-3859-2112, mgledhill@geomar.de) License: Creative Commons Attribution 4.0 International (CC-BY-4.0) (URI: https://creativecommons.org/licenses/by/4.0/) Status: Curation Level: Basic curation (URI: https://wiki.pangaea.de/wiki/Curation_levels) Size: 8 data points Files: All files referred to in data matrix can be downloaded in one go as ZIP or TAR (PANGAEA user account required). To download single files, use the filename from data matrix appended to "https://download.pangaea.de/dataset/993556/files/". */ Description Binary Binary (Size) [Bytes] Iron speciation calculated for surface waters (<100 m) data from GEOTRACES cruises GA02 and GA10 (see geotraces.org for more information on the cruises) A-GA02_GP16.v3.xlsx 25 kBytes A compilation of dissolved iron and iron speciation values for the surface ocean (mean for upper 100 m) derived from observations of iron in the literature combined with salinity, pH and dissolved organic carbon values that were kriged to a 2 degree grid from observations provided in GLDAPv2.2021 (Lauvset, S. K. et al. GLODAPv2.2022: the latest version of the global interior ocean biogeochemical data product. Earth System Science Data 14, 5543-5572 (2022)) and a dataset of dissolved organic carbon (Hansell, D. A. et al. Compilation of dissolved organic matter (DOM) data obtained from global ocean observations from 1994 to 2020 (NCEI Accession 0227166). (2021)) B-Global Fe speciation in surface waters_v2.xlsx 626.9 kBytes Iron speciation values matched to observations of Fe quotas (in laboratory and field), growth parameters (laboratory) and the abundance of transcripts for the iron stress ISIP protein. C-Iron Quotas_half sat constant_FeII_data.xlsx 221.2 kBytes Global distribution of iron speciation obtained by kriging values in B to a 2 degree grid, together with limiting nutrient and nutrient limited growth rates predicted with simple Monod type growth kinetics. D-Global_kriged_surface_ocean_values.v3.xlsx 3.1 MBytes