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and 4 - 6 mm long (Fig. 5b). The cells showed abun-
dant cell inclusions at their periphery, exhibited a
simple binary fission and were arranged in loose
colonies. The sheath was diffluent and hardly
visible. A. castagnei occurred only in deeper
biofilm parts of the tufa stromatolites (Fig. 5b).
In biofilms other than those on the tufa stromato-
lite surfaces, additional morphotypes were found,
e.g. Chamaesiphon at moss tufa with its spar
crusts and various coccoid and endolithic filamen-
tous cyanobacteria at the non-calcifying spring
sites. Often the identification of cyanobacteria mor-
photypes in tufa is not unambiguous in the literature,
i.e. the same morphotype may be assigned to differ-
ent species by different authors. Lyngbya sp. when
showing disc-shaped cells and a more distinct
sheath may be assigned to Lyngbya martensiana
(e.g. Stirn 1964). Also, the L. foveolarum morpho-
type may include other filamentous cyanobacteria
exhibiting filaments enclosed in a common sheath
in tufa biofilms, that is, Schizothrix pulvinata
(K¨tzing) Gomont (in Freytet & Plet 1996),
S. fasciculata (N¨geli) Gomont (in Rott 1994) and
S. calcicola (C. Agardh) Gomont in Szulc & Smyk
(1994). Phormidium calcareum K ¨tzing ex Star-
mach is distinguished from P. incrustatum by the
absence of a calyptra (Kann 1973) and, therefore,
both are treated as distinct taxa by Kom
´
rek &
Anagnostidis (2005), whereas Pentecost (2003) con-
siders both as synonymous.
Fig. 6. Morphology of cultured representative of the
Lyngbya sp. morphotype (strain WBK15, a member of
the 'Unidentified A' lineage, see Fig. 7). Note trichomes
enclosed within a firm sheath, cells with disc-shaped
appearance. Cells walls laterally inserted and no
constrictions at the cell boundaries. Scale bar is 25 mm.
(Gomont) Anagnostidis & Kom´rek morphotype
(P. foveolarum Montagne ex Gomont in Arp et al.
2001b; Freytet & Verrecchia 1998; Janssen et al.
1999) comprised also densely arranged erect fila-
ments with a thin, firm sheath. The trichomes were
rather thin, that is, 1.2 - 2.0 mm wide (Fig. 5a).
Their cells were half long as wide to isometric to
slightly longer than wide and slightly constricted
at cell walls. The apical cells were simple,
rounded or slightly tapering. The L. foveolarum
morphotype formed dense meadows of erect fila-
ments; it was particularly abundant in autumn.
Pseudanabaena sp. represented another filamentous
morphotype. It had a chain-like appearance, ovoid
to rounded barrel-shaped cells which were 2 mm
long and 1 mm wide (Fig. 5b). The filaments were
without sheath. The Pseudanabaena sp. morpho-
type was found in the deeper biofilm parts
(Fig. 5b). The Hyella fontana Huber & Jadin mor-
photype formed pseudofilaments from multiple fis-
sions that were bi- or triserial at the base, but
uniserial at the distal tips (Fig. 5c). Cells were
rounded-polygonal to elongated, 1.5 - 4.0 mmin
size. H. fontana occurred in deeper biofilm parts
and at growth discontinuities of the tufa stromato-
lites. Aphanothece castagnei (Br´bisson) Raben-
horst, mentioned previously by Thunmark (1926)
and Freytet & Plet (1996), was a unicellular mor-
photype at both karstwater streams. It exhibited
coccoid, oval-elongated
Cyanobacteria: a molecular approach. 16S rDNA
cloning and sequencing of environmental DNA
was performed at the site WB5 to investigate the
diversity of cyanobacteria of the biofilm (BF) and
the following annual stromatolite laminae couplets
(Core layers 'CL') from a 5 cm deep drilling core
(Fig. 10). A total of 711 cyanobacterial clones was
obtained and phylogenetically analyzed. The
clones were distributed on nine independent
lineages and clades of the 16S rDNA phylogeny
(Fig. 7). Each lineage has also been found at other
sites of the two karstwater streams in our ongoing
study. At other sampling sites only three to seven
cyanobacterial lineages have been retrieved from
the biofilm. Altogether, a total of 12 cyanobacteria
lineages which occurred at two and more sites
have been recovered. Identification of the recovered
cyanobacteria, however, appeared difficult because
for most lineages no closest neighbouring sequences
from named reference strains have yet become
available. Six cyanobacteria lineages (94% of all
clones) were retrieved from the biofilm (BF) with
frequencies higher than 1% of all clones (Fig. 7).
The biofilm was dominated by the lineages 'Uniden-
tified B' and Tychonema sp. (41% and 29% of all
BF clones). The Chamaesiphon sp., 'Unidentified
D' and 'Unidentified E' lineages were exclusively
cells, 2.5 - 3.5 mm wide
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