Microbial gangs are taking over the water column of a reconstructed lake A.
M.
2 Katsiapi ,
P.
1 Berillis ,
M.
2 Moustaka-Gouni ,
K. Ar.
1* Kormas
Department of Ichthyology & Aquatic Environment, University of Thessaly, 384 46 Nea Ionia, Greece *E-mail:
[email protected] 2 Department of Botany, School of Biology, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece
… the Mission
…the first Fingerprints…
To investigate the diversity of Lake Karla’s microbial community during the first year after its reconstruction
The Scene… Lake Karla
E u k a r y o t e s
a
P r o k a r y o t e s
N 39o 26΄Ν
22o 47΄Ε
The lake provides a unique chance to study the first microbial colonists in a natural scale aquatic environment
Methods used… Collection of surface water samples in March, April & June 2010 from an outshore station Molecular analysis (of samples collected in March 2010): Pre-filtering and then collection on 0.2 μm isopore filters, DNA extraction, 16S rRNA gene PCR amplification with the primers CYA106F, CYA781R(a), CYA781R(b), 18S rRNA gene PCR amplification with EukA and EukB primers, cloning and sequencing, phylogenetic analysis, neighbour-joining tree construction Microscopic analysis: Morphological identification of phytoplankton was performed in live and preserved (Lugol and formaldehyde) samples with a light microscope (under light and phase contrast). Phytoplankton counts were performed using the inverted microscope method.
March
a
25 Biomass (mg L-1)
Abundance (x107 ind. L-1)
12
NITZ
25
PSEU
PRYM
TOTAL
c
ANAB
RHOD
PRYM
CRYP
140
June
ANAB
NITZ
LIMN
PSEU
TOTAL
800
LEPT
PRYM
TOTAL
d
LEPT
TOTAL
e
b
THAL
April
LEPT
50
THAL
Biomass (mg L-1)
Abundance (x107 ind. L-1)
…the Challenge
Fig. 4: Micrographs of (a) Anabaenopsis cf. elenkinii, (b) Pfiesteria sp., (c) Prymnesium cf. parvum found in Lake Karla (scale: 10 μm)
Fig. 3: Phylogenetic tree of relationships of 16S rDNA of the prokaryotic phylotypes found in the water column of Lake Karla
…the Seen & Captured..
Abundance (x107 ind. L-1)
Τhe lake (ca. 80 was drained through a subterranean tunnel to Pagasitikos Gulf (Aegean Sea) in 1962 Small-scale marshes were preserved until today Refilling started in September 2009 from River Pinios (surface area 38 km2, max depth 1.5 m)
c
b
Fig. 1: Map of Lake Karla (The photograph on the upper right shows the lake’s refilling)
km2)
...the Suspects…
Biomass (mg L-1)
1
1 Oikonomou ,
ANAB
EUGL
CRYP
TOTAL
f
ANAB
TOTAL
Fig. 5: (a, c, e) Abundance (x107 individuals L-1) of the abundant phytoplankton species (>90% of the total); (b, d, f) Biomass (mg L-1) of the dominant phytoplankton species (>90% of the total) in March, April & June 2010, respectively. (ANAB=Anabaenopsis cf. elenkinii, NITZ=Nitzschia acicularis, LIMN=Limnothrix cf. redekei, PSEUD=Pseudoanabaena limnetica, PRYM=Prymnesium cf. parvum, THAL=Thalassiosira pseudonata, RHOD=Rhodomonas minuta, EUGL=Euglena sp., LEPT=Leptolyngbya sp., CRYP=Cryptomonas sp., TOTAL=Total Abundance or Biomass)
Fig. 2: Phylogenetic tree of relationships of 18S rDNA of the eukaryotic phylotypes found in the water column of Lake Karla
Phylotypes related to marine, brackish, inland water habitats, salt marshes, soil Occurrence and dominance of toxin-producers (Dinophytes, Haptophytes, Cyanobacteria) Dominance shift from spring-eukaryotes to summer-prokaryotes
The Verdict… The lake’s colonists consisted a diverse microbial community indicating a hypertrophic status
The found phylotypes and morphotypes were of aquatic and terrestrial origin including knowntoxin producers (species of Anabaenopsis, Planktothrix, Prymnesium, Pfiesteria) in high numbers In recent flooding events the drainage channel was open posing a threat to the receiving coastal area of the Pagasitikos Gulf due to organisms like Pfiesteria 14th International Conference on Harmful Algae, Crete, Greece 1-5 November 2010
