Organic biogeochemical studies within MARNAUT 2007
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description
MARNAUT 2007. Organic biogeochemical studies within MARNAUT 2007. Nicolas Chevalier, Ioanna Bouloubassi (LOCEAN). Objectives Approaches Sampling Collaborative work. MARNAUT 2007. Organic biogeochemical studies within MARNAUT 2007. Nicolas Chevalier, Ioanna Bouloubassi (LOCEAN). - PowerPoint PPT Presentation
Transcript of Organic biogeochemical studies within MARNAUT 2007
To assess microbial assemblages and To assess microbial assemblages and
microbially-driven biogeochemical processes microbially-driven biogeochemical processes
related to active and past fluid seepage at related to active and past fluid seepage at
cold seeps in the Marmara Seacold seeps in the Marmara Sea
To link biogeochemical processes and To link biogeochemical processes and
microbial assemblages to fluid seepage microbial assemblages to fluid seepage
patterns and dynamicspatterns and dynamics
More specifically we aim at :More specifically we aim at :
Defining the structure, diversity and functionning Defining the structure, diversity and functionning of microbial assemblages involved in the of microbial assemblages involved in the transformation of fluid transformation of fluid components (e.g., components (e.g., methane oxidationmethane oxidation, sulphate reduction, sulphide , sulphate reduction, sulphide oxidation...)oxidation...)
Understanding how microbial assemblages (and Understanding how microbial assemblages (and associated processes) respond to varying associated processes) respond to varying seepage activity, compostion and chemistry of seepage activity, compostion and chemistry of fluids, flow rates... and how they impact on the fluids, flow rates... and how they impact on the precipitation of authigenic mineralsprecipitation of authigenic minerals and on cold-and on cold-seep macrofaunaseep macrofauna
O
OX
OH
X’OH
OO X
Molecular Tools : lipid biomarkersMolecular Tools : lipid biomarkers
microbial cell membrane lipids as sources microbial cell membrane lipids as sources information (biomarkers) on the information (biomarkers) on the
composition composition and biogeochemistry of and biogeochemistry of microbial assemblagesmicrobial assemblages
Distinctive ‘taxonomic’ structural features > > community structureDistinctive ‘taxonomic’ structural features > > community structure
ConcentrationsConcentrations > > relative abundances of microbial groups> > relative abundances of microbial groups > > biomass of extant (active) organisms> > biomass of extant (active) organisms
Stable carbon isotopes > > carbon source utilized, carbon flowStable carbon isotopes > > carbon source utilized, carbon flow
Molecular Tools : lipid biomarkersMolecular Tools : lipid biomarkers
• Solvent extraction of lipids
• Chromatographic isolation of lipid biomarker classes
• Gas chromatography (GC)
• Gas chromatography-mass spectrometry (GC-MS)
• Isotope ratio monitoring-gas chromatography-mass spectrometry (GC-
irMS) *
• High performance liquid chromatography- mass spectrometry (HPLC-MS)
*
* in collaboration
Lipid biomarkers : analytical methodsLipid biomarkers : analytical methods
Undisturbed Sediments CoresUndisturbed Sediments Cores
Authigenic Crusts Authigenic Crusts
Microbial Mats, Benthic FaunaMicrobial Mats, Benthic Fauna
Samples to be taken in contrasted settings :Varying fluid seepageDifferent benthic activity
To be sub-sampled and conditionned on board
And to be shared for coupled investigations
This contribution to the MARNAUT project is viewed This contribution to the MARNAUT project is viewed as part of an integrated biogeochemical approach as part of an integrated biogeochemical approach and, as such, it requires strong interdisciplinary and, as such, it requires strong interdisciplinary couplingcoupling
More specifically we plan to tightly couple this study with:
Microbiology and molecular biology approaches (P. Lopez)
Fluid analyses and fluxes, biogeochemical reaction rates, transport/reaction models (V.
Aloisi)
Authigenic carbonate geochemistry (C. Pierre)
Biology of benthic fauna (Ifremer, Brest)
Previous and ongoing work at cold seeps in the framework of
MEDIFLUX (ESF) BIOZAIRE (IFREMER/TOTAL)
HERMES (EU)
C25 isoprenoids
PMI:0PMI:1-3C20 isoprenoids
Squ:0Cr
Cr:1H
H
.
C25 isoprenoidsPMI:3-5
C30 isoprenoids
C35 isoprenoids
Squ: 3-6
Biomarkers in Crusts(Olimpi mud volcano area -
MEDINAUT)Apolar compounds
Bouloubassi et al., (2006)
IbIc
IIa
IIb
IIc
IId
Archaeol
Hydroxyarchaeol
O
O
OH
X
X’
OH
O
O X
OH
O
O X
I
II
Polar compounds
Biomarkers in Crusts(Olimpi mud volcano area-
MEDINAUT)
Bouloubassi et al., (2006); Aloisi et al., 2002; Pancost et al., 2001
-100
-80
-60
-40
-20A
rch
aeo
l
OH
-Arc
hae
ol
PM
I PM
I:1-
5
Die
ther
s I
Die
ther
s II
ia15
FA
ME
ia17
FA
ME
Bis
Ho
mo
-aci
d
Bis
Ho
mo
-ol
cho
lest
ero
l
n-2
9 A
lkan
e
E
B
B
B
A
DG
DT
13C
‰
Biomarkers in Crusts(Olimpi & Anaximander mud volcano area)
Bouloubassi et al., (2006)
NAUTINIL 2003NAUTINIL 2003
Polar lipid patterns in carbonate crustsPolar lipid patterns in carbonate crusts
NL 14 CC5
NL 20 CC1Archaeol
Hydroxyarchaeol
O
O
OH
X
X’
OH
O
O X
OH
O
O X
Dialkyl Glycerol Diethers (DGD)
...and suite of sterols, alcohols, hopanols
CalderaCaldera
PockmarksPockmarks
GC/MS : Fraction hydrocarbures
n-alcanes (C14 – C34) : essentiellement sources terrigènes
crocetane PMI
hopanoïdes
Hopanoïdes (hopanes-hopènes, C27 - C32 : sources microbiennes - Bactéries
C20 et C25 Isoprénoïdes irréguliers : sources microbiennes - Archées
