[A-OS12] Marine ecosystems and biogeochemical cycles: theory, observation and modeling

[AOS12-P09] Performance of a neutral network model of marine dissolved organic carbon compounds and microbes

*Masahito Shigemitsu¹ (1.Japan Agency for Marine-Earth Science and Technology)

Keywords:microbes, global box model

Mechanisms behind longevity of marine dissolved organic carbon (DOC) still remain unknown. Marine biogeochemical models treating DOC, until now, have been built on an intrinsic recalcitrance concept that intrinsically recalcitrant compounds of DOC are formed via various biotic and abiotic processes (e.g., Yamanaka and Tajika, 1997). Recently, an emergent recalcitrance concept has been newly put forward. The concept considers that recalcitrance of DOC emerges as a result of complex network of microbes-DOC interactions. A mathematical model representing the concept has also been published (Mentges et al., 2019). In this study, I investigate whether the new model can reproduce the global DOC distributions or not. I incorporated the model into a global box model that separates the Atlantic from the Indian and Pacific Oceans. In the framework, I also include the calculation of radiocarbon of DOC. The model could reproduce the global DOC distributions by tuning the physiological parameters for microbes, but could not reproduce the radiocarbon ages of DOC. In order to reproduce the radiocarbon ages, several sources of external origins with old DOC should be considered. If the problem is solved, the new model will be promising tool to investigate the longevity of marine DOC.