ISSN 0913- 7467. Kagoshima University Research Center for the South Pacific. No.33. 1997.$1OF.! Tropical and subtropical marine single celled organisms as.
ISSN 0913 - 7467
Kagoshima University Research Center for the South Pacific
1997.$1OF.!
No.33
Tropical and subtropical marine single celled organisms as important producers of calcium-carbonate
•
•
Johann HoheneggerC~y4ij:1iJf~jHJfJ'E~) Seawater is satu-
Foraminifera, are extremely abundant in
rated with inorganic
coral reef environments. They protect their
carbon in the form of
protoplasm
by
calcium-carbonate
tests,
aqueous bicarbonate
working as microscopical greenhouses for
(RCa;). All plants as
symbiotic microalgae. Thus, Foraminifera
marine seeds and microalgae transfer inor-
are independent of food in such nutrition de-
ganic to organic carbon by assimilation, dem-
pleted environments like coral reefs. Al-
onstrating the important role of the carbon
though they consist of a single cell, these or-
cycle for all organisms including human be-
gamsms can get large sizes,
ings. Increasing salinity and pH, as found in
reaching few centimeters. Similar to stony
shallow tropical and subtropical marine envi-
corals, all larger foraminifers depend on light
sometimes
ronments, enrich the amount of carbonate-
that is essential for their symbionts. They are
ions (CO;-) in seawater, which are used by
restricted to shallow environments according
various organisms for the production of
to light availability necessary for algal pho-
calcium-carbonate shells and skeletons (Ca
tosynthesis. Nearshore areas of the North-
CO,,). Most of the calcium-carbonate deposits
west Pacific are characterized by a special
in marine environments are therefore of or-
group of larger Foraminifera with star-
ganic origin. Especially tropical and sub-
shaped tests growing up to 3mm and becom-
tropical marine environments are character-
ing extremely abundant in some coastal
ized by huge deposits, best known as coral reefs. Islands in the Tropical and Subtropical Pacific are surrounded by coral reefs, and the worlds largest barrier reef is located northeast off Australia. Three organism groups are responsible for the construction of coral reefs. Beside stonycorals and corallinacean algae, a group of single celled organisms related to amoebas, the
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areas. Deposition of empty tests on the
different methods of biological systematics
beaches results in accumulation of carbonate
were investigated and compared on various
sands consisting almost exclusively of these
data sets, criticizing all methods in use, inclu-
star-shaped tests, the so-called Hoshisuna.
sive of molecular genetic techniques.
Sedimentary carbonate deposits are found
In the early eighties again the interest on
through earth history in high number, where
the biology and ecology of Foraminifera
limestones became the mam reservoirs for
grew, resulting in the research on the micro-
fossil
larger
spatial distribution pattern of living smaller
Foraminifera are of 325,000,000 years age.
foraminifers of the Northern Adriatic Sea,
Since this time they became important in geo-
Italy. I got the first opportunity to investi-
logical investigation by their high evolution-
gate living larger Foraminifera at Sesoko Is-
ary rate useful for time determination of fos-
land, Okinawa as a guest of the Japan Society
sil shallow-water sediments (also in sequence
for the Promotion of Science in 1986. A one
stratigraphy)
year stay as an invited researcher at the
hydrocarbons.
and
The
the
oldest
interpretation of
Sesoko Station followed in 1992/93, where
paleo-environments. Interpretation of ancient environments by
population dynamic studies on Hoshisuna
larger foraminifers could only be done, when
were performed. As a by-product, the depth
the ecology of living forms is fully under-
distribution of other larger Foraminifera
stood. This is the reason, why a paleontolo-
was investigated and led to the results, that
gist likes me
investigates living larger
light intensity and water energy act as the
foraminifers in respect to their ecological de-
main environmental gradients for the distri-
mands
and
geographical
•
distribution.
bution of larger Foraminifera. A research
started my scientific research investigating
project on the statistical treatment of these
the distribution of foraminifers in an Upper
dependencies started in 1996, followed again
Triassic carbonate-platform complex more
by a 4 month stay as an invited researcher at
than 27 years ago. These 210,000,000 years old
the Tropical Biosphere Research
sediments represent the dominating rocks in
Okinawa during the summer of 1996.
Center,
the Northern Calcareous Alps of Austria,
Participating in the 1995 trip of the
Europe with mountains up to 3000m altitude.
Kagoshima University Research Center for
Some parts of these mountain ranges are fos-
the South Pacific to Belau confirmed the
sil coral reefs comparable to the modern ones.
depth dependency of different forms, but
Stony corals appeared first at the beginning
demonstrated the geographical differences in
of Triassic time.
the shallower forms living from the water
After this first treatment of fossil coral
surface down to 50m depth. This led me to
reefs and Foraminifera more than 25 years
investigate the geographical distribution of
ago I changed the scientific field to develop
larger foraminifers in the Pacific, which de-
special mathematical methods for classifica-
pends mainly on major water currents. The
tion and morphometry, leading to the propo-
'large scale distribution of larger foramini-
sition of a recognition concept for species,
fers' is also the title of the project I try to
which is based on similarities of ontogenetic
work on during my stay as an invited profes-
processes between organisms. Furthermore,
sor of the KURCP, especially regarding the
•
northern distribution boundaries of these
production of carbonates, but can be used
beautiful, not so small unicellular organisms,
also as indicators of pollution and major cli-
which are important not
matic changes.
only
for
the
2 I---~Ilmm
1. Calcarina gaudichaudii D'ORBIGNY 3. Baculogypsina sphaerulata
2. Calcarina defrancii
D'ORBIGNY
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