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Hyperbaric methods, procedures and techniques for the study of deep-sea microorganisms under in situ conditions

Abstract : The ocean is mostly deep, with most of its volume (>80%) at depths greater than 1000 m, and is poorly sampled (<0.01%). It is characterized by high hydrostatic pressure, low temperature, high inorganic nutrients and low organic carbon concentrations. The input of matter and energy is mainly driven from primary production at the surface in the form of particulate and dissolved organic matter and then exported to the seafloor through various export and transfer routes. The bioavailable particulate and dissolved fractions are mainly consumed in surface waters by prokaryotes, leaving only a fraction called refractory, more complex to degrade as the only source of carbon for prokaryotes in the deep ocean (bathypelagic zone). Most metabolic activity and diversity measurements of bathypelagic prokaryotes are generally underestimated due to technological limitations in recovering samples and maintaining them under in situ environmental conditions (high hydrostatic pressure, temperature, etc.). To study prokaryotes under in situ conditions, we have a hyperbaric technology to collect, transfer, and incubate samples under in situ conditions (high hydrostatic pressure and temperature) that is now commercialized and available to the scientific community. Using the versatility of our equipment, we can also simulate the increase of hydrostatic pressure along the water column. The results highlight that by maintaining pressure conditions, it is possible to sample piezophilic microorganisms (with an affinity to live under high hydrostatic pressure) representative of the deep environment. These results were confirmed in an experiment on the degradation of high molecular weight dissolved organic matter by a community adapted to the deep-sea environment. Finally, we have also shown the importance of environmental conditions to study the fate of organic matter in the water column.
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Contributor : Marc Garel Connect in order to contact the contributor
Submitted on : Thursday, January 6, 2022 - 8:35:46 AM
Last modification on : Saturday, January 8, 2022 - 3:02:59 AM
Long-term archiving on: : Thursday, April 7, 2022 - 6:27:27 PM


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  • HAL Id : tel-03513824, version 1


Marc Garel. Hyperbaric methods, procedures and techniques for the study of deep-sea microorganisms under in situ conditions. Ocean, Atmosphere. Aix-Marseille Université, 2021. English. ⟨NNT : ⟩. ⟨tel-03513824⟩



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