University of EssexUniversity of Essex

BIODEEP-WP3

Analysis of species diversity, community structures and phylogeny of microorganisms and meiofauna in the Mediterranean deep-sea hypersaline anoxic basins (DHAB)

Andrea Sass , Terry McGenity

Amplification with fluorescent eubacterial primers successful Water, brine and interface samples were all investigated

Not successful: amplification with Archaeal primers DNA extraction from most sediment samples amplification from Discovery brine and interface

Summary of achievements up to date:

Community structure fingerprinting via t-RFLP of 16S rDNA

Summary of previously presented results:

brines of each basin unique patterns l’Atalante and Bannock brines more similar patterns stable over time same patterns from Urania brines 1 and 2 number of fragments relatively small

Brine samples:

new achievements:

amplification from l‘Atalante and Bannock basin sediments successful

Bannock sediment sample and brine

Sediment top

Brine

Fragment length

RF

U

Amplification with eubacterial primers, digestion with AluI

Brine samples taken at same location and depth?

Brine

Sediment

L’Atalante sediment and brine

Sediment top covered with black ooze

Cruise 2002

Cruise 2002

Cruise 2001

amplification with -casein

Sediment top

Sediment top

Sediment top

Sediment bottom

amplification with -

caseine

extraction with phenol-chloroform

RF

U

Fragment length

Amplification with eubacterial primers, digestion with AluI

patterns from sediment samples very similar to brine samples no unique fragments found in sediment samples

Community in the sediments widely the same as in brines?

sediments consist mainly of brine both sediments and brine are anoxic

Extraction methods yield DNA only from the brine fraction of the sediment?

Interfaces

Patterns from interfaces unique for each basin and different from brines and oxic seawater

Certain fragments occur only at certain salinities within the interface

Unique community or accumulation of microorganisms from the water column?

Bannock interface samples taken in intervals at different salinities

Summary of previous presented results:

Salinity 25%= brine

Salinity 21.5%

Salinities 13.8-15.9%

Salinity 12.7%

Salinities 8.7-10.8%

Salinities 3.8-7.6%

Oxic water, 3000 m depth

Fragment length

Bannock interface

Amplification with eubacterial primers, digestion with AluI

RF

U

Sediment traps

2 weeks

6 months

12 months

Amplification with eubacterial primers, digestion with AluI

Fragment length

RF

U

new achievements:

investigation of Urania basin interface with greater spatial resolution

Salinity 5.7 ‰

Salinity 15.4 ‰

Salinity 6.3 ‰

Salinity 9.0 ‰

Salinity 13.1 ‰

Salinity 21.1 ‰

Salinity 15.6 ‰

Salinity 18.4 ‰

Brine

Urania interface

Amplification with eubacterial primers, digestion with AluI

Fragment length

RF

U

fingerprints change gradually from interface to brine no succession of microbial communities within interface

interface not as stable as Bannock interface?

Bannock and Urania upper interfaces:

community fingerprints are different from oxic deep-sea water

change in communcity structure starts at seawater salt concentration above the sampled interface?

Amplification with eubacterial primers, digestion with AluI

Fragment length

Urania interface compared with oxic water samples

samples taken 2001

RF

U

Urania interface

oxic water 3500m depth

oxic water 3000m depth

Different pattern in water and interface samples due to different amount of water filtered ?

Amplification with eubacterial primers, digestion with AluI

Patterns from the same DNA extract with different amounts of DNA addes to PCR reaction

Fragment length

RF

U

Summary of newly achieved results:

Microbial community in Bannock and l‘Atalante sediments similar to those in corresponding brines

Succession of different comminties at different salinities within the interface more pronounced in Bannock interface than in Urania interface

Upper interfaces different from sea water