Náttúrufræðingurinn - 1970, Blaðsíða 29

NÁTTÚRUFRÆÐINGURINN
23
SUMMARY
Al|íolo(;ical investigations around the coast of Iccland in 1963—1968
by Ivka Munda,
Biological Institute, Academy ol Sciences, Ljubljana, Yugoslavia
The author gives a short account ot her algological investigations around
the Icelandic coast from 1963 to 1968.
The main purpose of these annual investigations was to get a detailed
picturc of the distribution and ecology of benthic marine algae around the
Icelandic coast.
The influence ol' the Atlantic and Arctic waters on the benthic algal growth
was observed. Special emphasis was laid on the transitional areas in North-
east- and Southeast Iceland, wliere the algal vegetation pattern changes from
cold- or warm-boreal to subarctic vegetation.
The investigations began in 1963 in South Iceland. The following summers
different parts of the Icelandic coast were observed.
In South Iceland study was made of the quantity as well as the chemical
composition of Ascophyllum nodosum which covers great expansions of littor-
al slopes. Besides, the floristics and ecology of the algal vegetation of the area
was studied. These investigations were also meant to help in the evaluation of
Ascophyllum as eventual raw material for future use, bul this species could
be used in the food industry or as fodder and manure.
Considerable amounts of agar-yielding species — Gigartina stellata and
Chondrus crispus — were found in the south. Gigartina occupied the lower
littoral slopes while Chondrus was limited to the tidal pools.
The algal vegetation of southern Iceland proved to have a warmboreal
character due to the strong influence of Atlantic waters. Here littoral growth
occupies the extensive lava rocks and is represented by subsequent Fucaceae
zones: Pelvetia canaliculata — Fucus spiralis — F. vesiculosus — Ascophyllum
nodosum — Fucus distichus. However, the main warm-water species were found
in the numerous tidal pools and on lower littoral slopes.
In 1964 the northwestern part of the Icelandic coast was investigated. Main
attention was paid to the algal vegetation in Dýrafjörður. The gradient iu
the algal vegetation along the fjord coast was observed from the innermost
fjord regions and outward. It became evident that the algal vegetation along
the coastline of a fjord changes gradually in response to environmental
conditions. Estuarine algal associations were found in the inner fjord regions,
with a few species represented. The nuniber of species gradually increases to-
wards the outer regions of the fjord and different algal associations appear,
corresponding to the increasing degree of exposure and other changed eco-
logical conditions, such as temperature, salinity and configuration of the littoral
slopes.
The algal vegetation of Dýrafjörður proved to have cold-boreal character-
istics and was somewhat different from the vegetation found in the south.