|Title:||The effects of organic matter characteristics on Fe(II) oxidation kinetics in coastal seawater||Authors:||Santana Casiano, Magdalena
González Santana, David
González Dávila, Melchor
|UNESCO Clasification:||251002 Oceanografía química||Keywords:||Iron(II)
|Issue Date:||2023||Publisher:||Servicio de Publicaciones y Difusión Científica de la Universidad de Las Palmas de Gran Canaria (ULPGC)||Conference:||XXI International Iberian Marine Chemistry (SIQUIMAR 2022)||Abstract:||The iron (II) oxidation kinetic process was studied at 25 stations in coastal seawater of the Macaronesia region (9 around Cape Verde, 11 around the Canary Islands, 5 around Madeira). In a physicochemical context, experiments were carried out to study the pseudo-first order oxidation rate constant (k', min-1) over a range of pH (7.8, 7.9, 8.0, 8.1) and temperature (10, 15, 20, 25ºC). Deviations from the calculated k'cal at the same T, pH and S were observed for most of the stations. Measured t1/2 (ln2/k´, min) values at the 25 stations ranged from 1.82-3.47 min (mean 1.93±0.76 min) and for all but two stations were lower than the calculated t1/2 of 3.21±0.2 min. In a biogeochemical context, nutrients and variables associated with the organic matter spectral properties (CDOM and FDOM) were analyzed to explain the observed deviations. The application of a multilinear regression model indicated that k´ can be described (R=0.921, SEE=0.064 for pH=8 and T=25ºC) from a linear combination of three organic variables. k´OM = k´cal -0.11* TDN + 29.9 * bDOM + 33.4 * C1humic where TDN is the total dissolved nitrogen, bDOM is the spectral peak obtained from colored DOM analysis when protein-like or tyrosine-like components are present and C1humic is the component associated to humic-like compounds obtained from the parallel factor analysis (PARAFAC) of the fluorescent DOM. Results show that compounds with N in their structures principally explain the observed k´ increase for most of the samples. Although other components could also present a relevant role. Experimentally, k´ provides the net result between the compounds that accelerate the process and those that slow it down.||URI:||http://hdl.handle.net/10553/122215||ISBN:||978-84-9042-478-0||Source:||Abstracts XXI International Iberian Marine Chemistry (SIQUIMAR 2022) / coordinación, María Esther Torres Padrón, p. 12|
|Appears in Collections:||Ponencias|
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