Post on 29-Dec-2015
Structure of the microbial food webs at the air-water interface
Philippe Lebaron Ingrid Obernosterer
Observatoire Océanologique, Banyuls-sur-mer
- Study of the structure and function of biological communities in the sea-surface microlayer.
-Characterization of the bacterial community structure in the oligotrophic open ocean.
-Linking bacterial activity to major phylogenetic groups.
Objectives
The sea-surface microlayer
Ions moleculeshydrophobic
surfactants
hydrophilic surfactants
Bacterioneuston
Phytoneuston
Zooneuston
10-9
10-8
10-7
10-6 (1µm)
10-5
10-4
10-3 (1 cm)
0.01
Depth(m)
Pre
dato
r pr
essu
re
Hea
t con
duct
ion
0.1 (10 cm)G
as d
iffu
sion
Vironeuston
Sur
face
laye
r
Sur
face
cen
tila
yer
Sur
face
mil
lila
yer
Sur
face
mic
rola
yer
Sur
face
nan
olay
er
Air - water interface
Dissolved and ParticulateOrganic and Inorganic
MatterNeuston
Organic Matter
Phytoneuston
Protists
Bacterioneuston Viruses
Metazoans
Gases
Organic and Inorganic Particles
Gases
Sea
-su
rfac
e M
icro
laye
r
Sub-surface Waters
e.g. O2, CO2,DMS, CH4,
O2, CO2, N2
Photo--lysis
Bubble Ejection
Atm
osp
her
eSea-surface microlayer - Atmosphere Interactions
Enrichment factors for the sea-surface microlayer in the Mediterranean Sea
Metal Screen Glass Plate
Bacterial Abundance
Cultivable Bacteria
Chlorophyll a
Phaeophytin
Particulate Organic Carbon
Flagellates
1.1 1.2
11 13
5.4 2.8
1.8 0.7
9.9 1.0
10 n.d.
Bacterial Production
Community Respiration 7.5 n.d.
1.2 1.0
Paenibacillus glucanolyticus AB073189 (SML)
Planococcus rifietoensis AJ493659 (SML)
Exiguobacterium aurantiacum X70316 (5 strains SU)
Aeromicrobium erythreum AF005021
Aeromicrobium marinum AY166703
SML – 020
Nocardioides sp. AJ316318
Nocardioides jensenii Z78210
Blastococcus aggregatus L40614 (SU)
SML – 014
Corynebacterium ammoniagenes X84440
Dietzia maris Y18883 (2 strains SML)
Salinibacterium amurskyense AF539699
Marine bacterium AY188942
UW – 077
Microbacterium kitamiense AB013920 (SML)
Microbacterium esteraromaticum AB099658 (SML)
Brachybacterium arcticum (n.p.) AF434185 (SML)
Brachybacterium sacelli AJ415383
Arthrobacter agilis X80748 (3 strains SML)
Arthrobacter nitroguajacolicus AJ512504
0.01
FHGC
Actinobacteria
FLGC
Phylogenetic tree based on the 16S rDNA sequences of isolates belonged to the FHGC group. The tree was created using neighbor-joining method. The bar indicates a Kimura distance of 0.01.
A B
Linking structure and function
Measurements and Methods proposed
Characterization of the sea-surface microlayer (SML) -Sampling the SML (Metal Screen and Glass Plate)-Enumeration of heterotrophic and autotrophic community (flow cytometry)-Pigment analysis-POC and DOC-Activity measurements : Primary production and Community Respiration (O2-measurements), Bacterial Production (14C-Leucine incorporation)-Bacterial Diversity : SSCP and Cloning; Isolation of bacterial strains-MAR-FISH
Measurements in the water column
-Bacterial Diversity : SSCP -MAR-FISH
Sampling
Sea-surface microlayer Water Column
Zodiac Metal Screen & Glass Plate
time = f(Vol of water)
Metal Screen 5 L/hGlass Plate 2L/h (2 plates)1 sampling ≈ 1.5-2h, with 3 persons abord the zodiac
Frequency: 2 samplings/station - noon- midnight
High resolution depth profile (0-5m)(limited to 2-3 long stations)
Each Station-5 depths (above, below and in the DCM, 2 depths > 500 m )
-Bacterial abundance and diversity-MAR-FISH
-Water volume needed: 1.5-2L
-- Aerosols ???