Abstract. Marine particulate organic matter (POM) supports the vertical transport of organics in the oceans, and the ecology of microbes and filter feeders. POM is collected on GFF filters and quantified as particulate organic carbon (POC) and nitrogen (PON). The filtrate contains dissolved organic matter (DOM) that partly is abiotically converted into POM and can be collected on GFF filters. We filtered seawater from cultures and the pelagic ocean, after the initial sample filtration yielding the conventional POC/PON sample (POM1), we refiltered the filtrate yielding POM2, refiltering its filtrate we obtained POM3 and so on till POMi. Refiltered POM tended to the same concentration independent of the sample depth and even after a few refiltrations, independent of the original particulate organic load. POM2/POMi for surface water (< 100 m) was about 0.1 and for deep water (> 1000 m) was > 1.0. We considered adsorption of DOM and bacteria that had passed through the first filter but concluded that these could not explain the high POM concentration in the filtrates. We suggest that POM in filtrates represent gels formed due to hydraulic stress during filtration. The ratio of POM2/POMi will partly depend on environmental conditions like turbulent energy. We suggest that the increase of POM2/POMi with depth is related to the lower in situ turbulent energy at greater depth. We discuss aspects of POM methodology, including problems with acidification of samples, and the wider ecological implications of our results.
This preprint has been withdrawn.
How to cite. Valdes Villaverde, P., Almeda Jauregui, C., and Maske, H.: Rapid abiotic transformation of marine dissolved organic material to particulate organic material in surface and deep waters, Biogeosciences Discuss. [preprint], https://doi.org/10.5194/bg-2020-291, 2020.
Received: 26 Jul 2020 – Discussion started: 31 Aug 2020
The oceans sequester more than 1/4 of the anthropogenic CO2, mainly through the sinking of organic particles (POM) to the seafloor. POM samples are collected on filter; the filtrate is expected to contain only dissolved organic material, but we found unexpectedly high POM when the filtrate was refiltered. We interpret this POM as gels that were formed in the filtrate by hydraulic stress during the filtration. In deep water samples the POM collected can be less than the POM in the filtrate.
The oceans sequester more than 1/4 of the anthropogenic CO2, mainly through the sinking of...