Contribution of structural recalcitrance to the formation of the deep oceanic dissolved organic carbon reservoir

Wang, N, Luo, Y-W, Polimene, L, Zhang, R, Zheng, Q, Cai, R and Jiao, N 2018 Contribution of structural recalcitrance to the formation of the deep oceanic dissolved organic carbon reservoir. Environmental Microbiology Reports.

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The origin of the recalcitrant dissolved organic carbon (RDOC) reservoir in the deep ocean remains enigmatic. The structural recalcitrance hypothesis suggests that RDOC is formed by molecules that are chemically resistant to bacterial degradation. The dilution hypothesis claims that RDOC is formed from a large diversity of labile molecules that escape bacterial utilization due to their low concentrations, termed as RDOCc. To evaluate the relative contributions of these two mechanisms in determining the long‐term persistence of RDOC, we model the dynamics of both structurally recalcitrant DOC and RDOCc based on previously published data that describes deep oceanic DOC degradation experiments. Our results demonstrate that the majority DOC (84.5±2.2%) in the deep ocean is structurally recalcitrant. The intrinsically labile DOC (i.e., labile DOC that rapidly consumed and RDOCc) accounts for a relatively small proportion and is consumed rapidly in the incubation experiments, in which 47.8±3.2% of labile DOC and 21.9±4.6% of RDOCc is consumed in 40 days. Our results suggest that the recalcitrance of RDOC is largely related to its chemical properties, whereas dilution plays a minor role in determining the persistence of deep‐ocean DOC.

Item Type: Publication - Article
Additional Information. Not used in RCUK Gateway to Research.: This is the pre-peer reviewed version which has been published in final form at This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.
Divisions: Plymouth Marine Laboratory > Science Areas > Marine System Modelling
Depositing User: Kim Hockley
Date made live: 10 Oct 2018 10:08
Last Modified: 13 Dec 2023 12:21

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