that have been isolated from this type of
springs are Archaebacteria which live at
75-90°C (Fig. 7). These include the aero-
bic Sulfolobus, and the anaerobes Therm-
oproteus (Fig 8), Thermofilum and De-
sulfurococcus. These bacteria all utilize
either sulfide or sulfur in their metabolism.
In fumaroles the green algae Cyanidium
caldarium can grow in the steam-zone at
40-50°C and pH 4 (Fig. 9).
Submarine hot springs are known at a
few places around Iceland and one is at
Reykjanes in ísafjarðardjúp. With the
help of K.O. Stetter samples were collect-
ed from hot springs at a depth of about 2 m
and with temperatures of 5080°C.
Several interesting salt-tolerant, thermop-
hilic bacteria were isolated from the samp-
les (Fig. 11). Bacteria of the genus Therm-
us have been found ín the hot tap water in
Reykjavík. Thermal brines are known on
the Reykjanes peninsula but no organisms
have yet been found in them. Iceland of-
fers an exceptional opportunity to carry
out research in hot spring biology and it
can be concluded that at present we know
only a small fraction of the organisms that
live in the hot springs.