Dissolved Organic Matter: Difference between revisions
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Revision as of 14:25, 20 November 2025
Overview
At approximately 662 gigatons of carbon (GtC), Dissolved Organic Matter (DOM) far outnumbers Particulate Organic Matter, which includes organisms and marine snow, and constitutes more than 99% of organic carbon in the ocean's water column[1]. Yet, most DOM released by phytoplankton, the primary source of DOM, is quickly degraded by heterotrophs within hours to days[2]. As a result, the majority of DOM (~630 GtC) that is found in the ocean has a lifetime (determined via 14C-carbon dating) of over 16,000 years[3]. DOM is operationally classified into the following groups based on their lifetime[4]:
- labile DOM (removal within hours to days)
- semi-labile DOM (removal within weeks to months)
- semi-refractory DOM (removal over years to decades)
- refractory DOM (removal over centuries to millenia)
Definition by experimentalist
DOM is operationally defined as organic carbon that flows through a GF/F glass fiber filter, with the retentate on the filter being defined as Particulate Organic Matter. On a molecular level, DOM comprises thousands or even millions of unique structures[5]. Most studies investigating the molecular composition of DOM resort to PPL-SPE, a moderately hydrophobic solid phase extraction technique designed to extract the largest possible amount of DOM from seawater while removing salts that can interfere with downstream analytical processes[6]. This fraction of DOM is called SPE-DOM (3).
Definition by modeler
Models represent DOM as groups of organic carbon as listed above (labile, semi-labile, semi-refractory and refractory) with varying lifetime as only descriptor[7], sometimes adding an ultra-refractory group[8].
References
- ↑ Hansell, D.A., C.A. Carlson, D.J. Repeta, and R. Schlitzer. 2009. Dissolved organic matter in the ocean: A controversy stimulates new insights. Oceanography 22(4):202–211, https://doi.org/10.5670/oceanog.2009.109
- ↑ Dittmar, T., Lennartz, S.T., Buck-Wiese, H. et al. Enigmatic persistence of dissolved organic matter in the ocean. Nat Rev Earth Environ 2, 570–583 (2021). https://doi.org/10.1038/s43017-021-00183-7
- ↑ Dittmar, T., Lennartz, S.T., Buck-Wiese, H. et al. Enigmatic persistence of dissolved organic matter in the ocean. Nat Rev Earth Environ 2, 570–583 (2021). https://doi.org/10.1038/s43017-021-00183-7
- ↑ Dittmar, T., Lennartz, S.T., Buck-Wiese, H. et al. Enigmatic persistence of dissolved organic matter in the ocean. Nat Rev Earth Environ 2, 570–583 (2021). https://doi.org/10.1038/s43017-021-00183-7
- ↑ Dittmar, T., Lennartz, S.T., Buck-Wiese, H. et al. Enigmatic persistence of dissolved organic matter in the ocean. Nat Rev Earth Environ 2, 570–583 (2021). https://doi.org/10.1038/s43017-021-00183-7
- ↑ Dittmar, T., Koch, B., Hertkorn, N., Kattner, G., (2008), A simple and efficient method for the solid-phase extraction of dissolved organic matter (SPE-DOM) from seawater, Limnol. Oceanogr. Methods, 6, https://doi:10.4319/lom.2008.6.230
- ↑ Kim, H. H. (2025). BATS-1D-VAR v1.0: A One-Dimensional Variational Data Assimilative Biogeochemical Model of the Bermuda Atlantic Time-Series Study (BATS) Site. Zenodo. https://doi.org/10.5281/zenodo.17148897
- ↑ Emily J. Zakem et al., Functional biogeography of marine microbial heterotrophs. Science388, eado5323 (2025). https://doi.org/10.1126/science.ado5323