BioDeep Meeting V: Marseilles, th April 2002 (1 st report) Workpackage 5 : Microbial metabolic activities Armand Bianchi, Jean Garcin, Christian Tamburini Proof for the existence of bacterial life in extreme and selective environments (high pressure, anoxia, hypersalinity…) 1 - BioDeep – WP5 – Marseilles, 13-15th April 2002

Sampling? Interface brine-sediments and sediments with multicorrer Brines with Niskin and HP5L fitted on the Scipack Seawater-Brine interface with Niskin fitted on the Scipack Normal seawater with HPSS 2 - BioDeep – WP5 – Marseilles, 13-15th April 2002

Bacterial production Respiration (CO 2 ) prokariotic Organic polymers Uptake of compounds < 600 Da organic monomers Topics and measurements realized ectoenzymatic activities 3 - BioDeep – WP5 – Marseilles, 13-15th April 2002

pmol L EAA PA Glutamate uptake (pmol L -1 ) Depth (m) 0510 Bacterial production (ng C L -1 ) GR BP GA References for ectoenzymatic activity, bacterial production and glutamic acid uptake in the whole “normal” water column GA: glutamic acid assimilation GR: glutamic acid respiration BP: bacterial biomass EAA: aminopeptidase activity PA: phosphatase activity 4 - BioDeep – WP5 – Marseilles, 13-15th April 2002

L’Atalante basin: an exemple of vertical profile of aminopeptidase rates nmol L -1 h -1 "Normal" sea-water 3000m-depth Seawater – brine interface Body brine Brine – sediment interface µmol L -1 h -1 Sediment 0-2 cm Sediment 2-4 cm 5

Seawater – brine interface: differences between rates for the four basins D: Discovery A: L’Atalante U: Urania B: Bannock DW: Deep-water Aminopeptidase pM h DAUBDW Phosphatase DAUBDW Glutamate Assimilation pM h Glutamate respirationBacterial Production ng C L -1 h -1 DAUBDWDAUB DAUB n.d. n.d.: not determined 6

Body brine: differences between rates for the four basins Aminopeptidase pM h Phosphatase Glutamate Assimilation pM h Glutamate respirationBacterial Production ng C L -1 h -1 D: Discovery A: L’Atalante U: Urania B: Bannock DW: Deep-water DAUBDW DAUB DAUB DAUB DAUBDW n.d. n.d.: not determined 7

Body brine: differences between rates for the four basins Aminopeptidase pM h Phosphatase D: Discovery A: L’Atalante U: Urania B: Bannock DW: Deep-water DAUBDW DAUB n.d.: not determined Glutamate Assimilation pM h Glutamate respirationBacterial Production ng C L -1 h -1 DAUBDW DAUB DAUBDW n.d. 7

Brine – sediment interface : differences between rates for the four basins AminopeptidasePhosphatase Glutamate respiration n.d. Glutamate Assimilation n.d pM h n.d pM h D: Discovery A: L’Atalante U: Urania B: Bannock SW: Sediments outside basin DAUBSWDAUB DAUB DAUB n.d.: not determined 8

Sediments: differences between rates for the four basins AminopeptidasePhosphatase Glutamate respiration µM h nM h D: Discovery A: L’Atalante U: Urania B: Bannock SW: Sediments outside brine DAUBSWDAUB DAUB l.d. l.d.: lower than detectable l.d. DISCOVERY sediments collected with box correr (Biodeep cruise – August 2000) 10 - BioDeep – WP5 – Marseilles, 13-15th April 2002

Sediments: differences between rates for the four basins AminopeptidasePhosphatase Glutamate respiration µM h nM h D: Discovery A: L’Atalante U: Urania B: Bannock SW: Sediments outside brine DAUBSWDAUB DAUB l.d. l.d.: lower than detectable l.d. 9 - BioDeep – WP5 – Marseilles, 13-15th April 2002

Are DHABs’ bacteria adapted to these extreme environmental conditions? - HP: samples maintained in ambient condition (anoxia, high pressure, ionic equilibrium…) + guarantee for aseptic condition -DEC: samples decompressed (change in pressure, ionic equilibrium,anoxia?…) 10 - BioDeep – WP5 – Marseilles, 13-15th April 2002 High Pressure Bottle

Are DHABs’ bacteria adapted to these extreme environmental conditions? Average = 10.3 n = 13 Pe NSW Average = 11,5 n = 7 Pe brine Pe = HP DEC rates measured on samples decompressed rates measured in ambient condition = 11

Conclusion  Bacterial activities were detected within all niches sampled: seawater – brine interface, brine, brine – sediment interface and sediment of all DHABs  Distribution of studies activities within the different niches differ for each basin  Aminopeptidase activity was higher in brines comparatively to "normal" deep-sea water  Glutamic acid uptake in DHABs sediment was lower than in "normal" deep sediments  Brine-living bacteria appear to be adapted to these special ambient conditions (high pressure, high salinity, anoxia,…) It’s the first demonstration of bacterial activities using an experimental strategy which avoided pressure, oxic, …, stresses during retrieval, incubation and sub-sampling BioDeep – WP5 – Marseilles, 13-15th April 2002

Discussion… Interface or brine sampling? 12 - BioDeep – WP5 – Marseilles, 13-15th April 2002  Bacteria adapted?  But also bacteria originated of the seawater column We pointed out life and activities with bacteria adapted We need result. Is it possible to have safe samples in interface like within the body brine? We have seen the difficulties to compare results obtained at the interface. Maybe, it is more reasonnable to intensify sampling within the bodin brine…

Thanks for your attention…