Proton binding characteristics of dissolved organic matter extracted from the north atlantic
Marine dissolved organic matter (DOM) presents key thermodynamic properties that are not yet fully constrained. Here, we report the distribution of binding sites occupied by protons (i.e., proton affinity spectra) and parametrize the median intrinsic proton binding affinities (log K-H) and heterogen...
| Autores: | ; ; ; ; |
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| Tipo de documento: | Artigo |
| Estado: | Published version |
| Data de publicação: | 2024 |
| País: | España |
| Recursos: | Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya) |
| Repositório: | Recercat. Dipósit de la Recerca de Catalunya |
| OAI Identifier: | oai:recercat.cat:10459.1/465073 |
| Acesso em linha: | https://doi.org/10.1021/acs.est.3c01810 https://hdl.handle.net/10459.1/465073 |
| Nível de acesso: | Acesso aberto |
| Palavra-chave: | DOM Nonideal competitive adsorption (NICA) Donnan |
| Resumo: | Marine dissolved organic matter (DOM) presents key thermodynamic properties that are not yet fully constrained. Here, we report the distribution of binding sites occupied by protons (i.e., proton affinity spectra) and parametrize the median intrinsic proton binding affinities (log K-H) and heterogeneities (m), for DOM samples extracted from the North Atlantic. We estimate that 11.4 +/- 0.6% of C atoms in the extracted marine DOM have a functional group with a binding site for ionic species. The log K-H of the most acidic groups was larger (4.01-4.02 +/- 0.02) than that observed in DOM from coastal waters (3.82 +/- 0.02), while the chemical binding heterogeneity parameter increased with depth to values (m(1)= 0.666 +/- 0.009) ca. 10% higher than those observed in surface open ocean or coastal samples. On the contrary, the log K-H for the less acidic groups shows a difference between the surface (10.01 +/- 0.08) and deep (9.22 +/- 0.35) samples. The latter chemical groups were more heterogeneous for marine than for terrestrial DOM, and m(2) decreased with depth to values of 0.28 +/- 0.03. Binding heterogeneity reflects aromatic carbon compounds' persistence and accumulation in diverse, low-abundance chemical forms, while easily degradable low-affinity groups accumulate more uniformly in the deep ocean. |
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