Organic carbon export and loss rates in the Red Sea

Kheireddine, M, Dall'Olmo, G, Ouhssain, M, Krokos, G, Claustre, H, Schmechtig, C, Poteau, A, Zhan, P, Hoteit, I and Jones, BH 2020 Organic carbon export and loss rates in the Red Sea. Global Biogeochemical Cycles.

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The export and fate of organic carbon in the mesopelagic zone are still poorly understood and quantified due to lack of observations. We exploited data from a BGC‐Argo float that was deployed in the Red Sea to study how a warm and hypoxic environment can affect the fate of the organic carbon in the ocean’s interior. We observed that only 10% of the particulate organic carbon (POC) exported survived at depth due to remineralization processes in the upper mesopelagic zone. We also found that POC exported was rapidly degraded in a first stage and slowly in a second one, which may be dependent on the palatability of the organic matter. We observed that AOU‐based loss rates (a proxy of the remineralization of total organic matter) were significantly higher than the POC‐based loss rates, likely because changes in AOU are mainly attributed to changes in dissolved organic carbon. Finally, we showed that POC‐ and AOU‐based loss rates could be expressed as a function of temperature and oxygen concentration. These findings advance our understanding of the biological carbon pump and mesopelagic ecosystem.

Item Type: Publication - Article
Additional Keywords: Carbon export Carbon loss rates Mesopelagic zone Temperature Oxygen Tropical ecosystem
Divisions: Plymouth Marine Laboratory > National Capability categories > National Centre for Earth Observation
Plymouth Marine Laboratory > Science Areas > Earth Observation Science and Applications
Depositing User: S Hawkins
Date made live: 21 Oct 2020 09:44
Last Modified: 22 Oct 2020 12:59

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