Tufa-forming biofilms of German karstwater streams: microorganisms, exopolymers, hydrochemistry and calcification - Tufas and Speleothems: Unravelling the Microbial and Physical Controls - page 84

Fig. 2. Field views of tufa-forming karstwater streams in Germany investigated in this study. (a) Westerh¨ fer Bach,
western Harz Foreland. (b) Deinschwanger Bach, Franconian Alb. (c) Reinsgraben at the Schillerwiese in G ¨ ttingen.
(d) 'Steinerne Rinne' at Erasbach, Franconian Alb. Image courtesy of Ch. Heim.

Additional hydrochemical analyses have been
carried out at two further streams (Fig. 1):

750, north 54 44 250 [spring; 509 m above
S.L.] to east 44 57 790, north 54 44 360
[lower end of tufa canal; 486 m above S.L.]).
The spring of the Steinerne Rinne at Erasbach
discharges from the base of the Weißjura-
aquifer, similar to the Deinschwanger Bach
(Meyer & Schmidt-Kaler 1983; Glassl &
Schieber 1990; Baier 2002). The catchment
area is less than 1 km 2 , covered exclusively
by deciduous and coniferous forest. This 'self-
built tufa canal' of the Erasbach rivulet has a
total length of c. 80 m and attains a maxi-
mum height of 77 cm (Baier 2002), and is
now protected as a nature monument. There
are no additional side springs or seepage
sites contributing water to this tiny rivulet.

(1) The Reinsgraben (RG, Fig. 2c) is situated at the

eastern city margin of G ¨ttingen, Leine Hills
(Geological Map of Lower Saxony 1:25 000
Sheet 4425 G ¨ttingen, east 35 66 625, north
57 11 675 [spring, 215 m above S.L.] to east
35 65 780, north 57 11 500 [lower stream
section, 172 m above S.L.]). The spring is fed
from the Middle Triassic Muschelkalk-Group
aquifer (i.e. similar to Westerh ¨fer Bach), at
the eastern main fault of the Leinetalgraben,
where impermeable Lower Jurassic claystones
force the groundwater to discharge (von
Koenen 1907; Stille 1932). The catchment
area is approximately 1 km 2 and covered by
deciduous forest. The beck has been investi-
gated at a length of 720 m, where it crosses
the park area of the Schillerwiese.

Hydrochemistry of stream waters
General characteristics of spring and
stream waters

(2) The Steinerne Rinne (SR, Fig. 2d) is situated

1.3 km south of the village Erasbach, southern
Franconian Alb (Geological Map of Bavaria
1:25 000 Sheet 6834 Berching, east 44 57

The investigated karstwater streams either belong
to the calcium-bicarbonate (Deinschwanger Bach