Náttúrufræðingurinn

						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 50—80°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.

68