View source for Dissolved Organic Matter

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* [[Page authors|Page authors]]: [[User:Hagi BucknWise|Hagen Buck-Wiese]]
* [[Responsible curator|Responsible curator]]:  [[User:Hagi BucknWise|Hagen Buck-Wiese]]

== Conceptual definition ==
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<ref>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</ref>. Yet, most DOM released by [[phytoplankton]], the primary source of DOM, is quickly degraded by [[heterotrophy | heterotrophs]] within hours to days<ref name="Dittmar et al. 2021">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</ref>. 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<ref name="Dittmar et al. 2021"/>. <br>

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]], and classified into the following groups based on their lifetime<ref name="Dittmar et al. 2021"/>:
*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)

== Subfield notes ==
=== Experimental ===
On a molecular level, DOM comprises thousands or even millions of unique structures<ref name="Dittmar et al. 2021"/>. 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<ref>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</ref>. This fraction of DOM is called SPE-DOM (3).

=== Models ===
Models represent DOM as groups of organic carbon as listed above (labile, semi-labile, semi-refractory and refractory) with varying lifetime as only descriptor<ref>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</ref>, sometimes adding an ultra-refractory group<ref>Emily J. Zakem et al., Functional biogeography of marine microbial heterotrophs. Science388, eado5323 (2025). https://doi.org/10.1126/science.ado5323</ref>.

== References ==
<references />

== Contributors ==
[[User:Hagi BucknWise|Hagi BucknWise]]

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