TY - JOUR
T1 - Dissolved organic carbon contribution to oxygen respiration in the central Red Sea
AU - Calleja Cortes, Maria de Lluch
AU - Al-otaibi, Najwa Aziz
AU - Moran, Xose Anxelu G.
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: We gratefully acknowledge the crew of the workboat R.V. KAUST Explorer and all the personnel from the coastal and marine resources core lab (CMORE) for their diligent fieldwork assistance. M. Viegas, L. Silva and S. Ivetic (KAUST) aided with fieldwork and sample collection. This research was supported by King Abdullah University for Science and Technology through the baseline funding provided to X.A.G. Morán.
PY - 2019/3/18
Y1 - 2019/3/18
N2 - In oligotrophic waters, dissolved organic carbon (DOC) is mostly produced in the surface layers by phytoplankton and remineralized by heterotrophic prokaryotes throughout the water column. DOC surface excess is subducted and exported to deeper layers where a semi-labile fraction is further processed contributing to oxygen consumption. How this cycling of DOC occurs in the Red Sea, one of the warmest oligotrophic marine basins, is virtually unknown. We examined DOC vertical and seasonal variability in a mesopelagic station (ca. 700 m depth) of the central Red Sea performing monthly profile samplings over a two-year period. Together with DOC vertical and seasonal distribution we evaluated the interaction with heterotrophic prokaryotes and contribution to oxygen respiration. DOC values ranged from 41.4 to 95.4 µmol C L-1, with concentrations in the epipelagic (70.0 ± 7.5 µmol C L-1) 40% higher on average than in the mesopelagic (50.7 ± 4.1 µmol C L-1). Subduction of seasonally accumulated semi-labile DOC was estimated to be responsible for ∼20% of the oxygen consumption mostly occurring at the low epipelagic-upper mesopelagic boundary layer. Variability in mesopelagic waters was higher than expected (ca. 20 µmol C L-1) evidencing a more active realm than previously thought, with consequences for carbon sequestration.
AB - In oligotrophic waters, dissolved organic carbon (DOC) is mostly produced in the surface layers by phytoplankton and remineralized by heterotrophic prokaryotes throughout the water column. DOC surface excess is subducted and exported to deeper layers where a semi-labile fraction is further processed contributing to oxygen consumption. How this cycling of DOC occurs in the Red Sea, one of the warmest oligotrophic marine basins, is virtually unknown. We examined DOC vertical and seasonal variability in a mesopelagic station (ca. 700 m depth) of the central Red Sea performing monthly profile samplings over a two-year period. Together with DOC vertical and seasonal distribution we evaluated the interaction with heterotrophic prokaryotes and contribution to oxygen respiration. DOC values ranged from 41.4 to 95.4 µmol C L-1, with concentrations in the epipelagic (70.0 ± 7.5 µmol C L-1) 40% higher on average than in the mesopelagic (50.7 ± 4.1 µmol C L-1). Subduction of seasonally accumulated semi-labile DOC was estimated to be responsible for ∼20% of the oxygen consumption mostly occurring at the low epipelagic-upper mesopelagic boundary layer. Variability in mesopelagic waters was higher than expected (ca. 20 µmol C L-1) evidencing a more active realm than previously thought, with consequences for carbon sequestration.
UR - http://hdl.handle.net/10754/631746
UR - https://www.nature.com/articles/s41598-019-40753-w
UR - http://www.scopus.com/inward/record.url?scp=85063036418&partnerID=8YFLogxK
U2 - 10.1038/s41598-019-40753-w
DO - 10.1038/s41598-019-40753-w
M3 - Article
C2 - 30886181
SN - 2045-2322
VL - 9
JO - Scientific Reports
JF - Scientific Reports
IS - 1
ER -
