GEOLOGICA CARPATHICA, 52, 6, BRATISLAVA, DECEMBER 2001
361 — 374
ECOLOGY OF KARPATIAN (EARLY MIOCENE) FORAMINIFERS
AND CALCAREOUS NANNOPLANKTON FROM LAA AN DER THAYA,
LOWER AUSTRIA: A STATISTICAL APPROACH
SILVIA SPEZZAFERRI and STJEPAN CORIC
Institute of Paleontology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; silvia.spezzaferri@univie.ac.at;
stjepan.coric@univie.ac.at
(Manuscript received July 25, 2001; accepted in revised form October 5, 2001)
Abstract: In this study we present a paleoecological interpretation based on quantitative analysis of middle Karpatian
(latest Burdigalian) benthic and planktonic foraminifers and calcareous nannofossils from Hole BL 503 (Wienerberger)
drilled at Laa an der Thaya, Lower Austria. Multivariate statistics based on the Bray-Curtis Similarity, non-metric
MultiDimensional Scaling (nMDS) and Similarity and Dissimilarity Term Analyses are applied to raw data to identify
the ecological gradients subtending the assemblages. Species abundance curves (%) were also plotted. A paleoclimatic
curve was obtained using the algebraic sum of planktonic foraminifers warm- and temperate-water indicators (positive)
and cool-water indicators (negative) to highlight the paleoclimatic trend during the middle Karpatian. Our data indicate
that the sediments drilled at Laa Th. were deposited in water depth not exceeding 200 m, relatively “near shore” in an
environment characterized by a generally high concentration of organic matter, suboxic to dysoxic conditions, high
nutrient availability, variable salinity and generally cool paleoclimate. On the basis of nannoplankton distribution we
also suggest that nutrient availability and upwelling conditions, rather than other ecological factors, control the distribu-
tion of calcareous nannoplankton in the Molasse Basin.
Key words: Miocene, Karpatian, Lower Austria, Laa an der Thaya, foraminifers, nannofossils, ecology, statistic.
Introduction
The Mediterranean Sea and the intracontinental Paratethys
were formed as new marine realms during the Late Eocene.
From the Oligocene through the Miocene the Paratethys un-
derwent a complex evolution that produced deep environmen-
tal changes with alternate opening and closing of efficient ma-
rine connections with the Indian Ocean on the East and the
Mediterranean Sea on the West (Rögl 1999).
This research represents the first attempt at paleoecological
reconstruction of part of the Laa Formation drilled and cored
(Hole BL 503, Wienerberger) at Laa an der Thaya (Laa Th.,
hereafter) in the Molasse Basin, Lower Austria, spanning the
Middle Karpatian (Latest Burdigalian) (Fig. 1). The type lo-
cality of the Laa Fm was established in the brickyard at
Brandhuber (now Wienerberger). The sediments consist of
blue-gray marl and fine sand becoming greenish upward. Dia-
tom-rich sediments also belonging to the Laa Fm were found
in Washerbergzone, 5 km eastern of Laa Th. (Grill 1968). Hole
BL 503 was drilled just outside the Wienerberger brickyard.
Sediments consist of approximately 2 meters of Quaternary
loess with sand passing to yellow brownish sand containing
variable amounts of silt down to approximately 6 m. They can
be correlated to the upper part of the sequence outcropping in
the brickyard and consisting of shallow-water deposits, discor-
dantly overlying the calcareous shales. Karpatian homoge-
neous gray silt and marl with randomly distributed 1-cm thick
fine sandy layers occur from 6 m down to 30 m. These sandy
layers are interpreted as distal fans (Rögl., pers. comm.).
Materials and methods
Two hundred grams of sediment for each sample were
soaked in gasoline for several hours to desegregate the sedi-
ments without damaging the specimens and to retain the origi-
nal faunal composition. Samples were then soaked in warm
water and washed under running water through >250 µm,
250—125 µm and >63 µm mesh sieves. The washed residues
were split, according to Rupp (1986), to obtain approximately
300 to 500 hundred specimens per fraction. Specimens of
benthic and planktonic foraminifers were picked from the
three fractions of one split per sample, identified with a binoc-
ular microscope and counted. Smear slides were prepared fol-
lowing Perch-Nielsen (1985) and studied under light micro-
scope with a 1000
×
magnification. Approximately 350
specimens for each sample were counted.
The raw data (Table 1) were then transformed into percent-
ages over the total abundance and percent abundance curves
were plotted (Fig. 2). Species with phylogenetic affinities and
similar environmental significance were also grouped to better
interpret their distribution patterns (Fig. 3, Table 2).
Corresponding author: Silvia Spezzaferri, silvia.spezzaferri@univie.ac.at
362 SPEZZAFERRI and CORIC
Univariate and multivariate statistics are applied to quantita-
tive data using the Software PRIMER 5 (Plymouth Marine
Laboratory). Application of this method to planktonic and
benthic foraminifers is extensively discussed in Basso & Spez-
zaferri (2000). However, it was never applied to compare nan-
nofossil and foraminiferal assemblages from the Molasse Ba-
sin. Data are double-squared root transformed (no standardi-
zation, no further species reduction), in order to highlight the
contribution of the less abundant species and simplify the in-
terpretation of the data structure (Field et al. 1982). Data are
used for hierarchical agglomerative clustering based on the
Bray-Curtis Similarity (Figs. 4A—C; Clifford & Stephenson
1975). Group Average Linking is used for benthic and plank-
tonic foraminifers, and Complete Linkage is applied to calcar-
eous nannoplankton assemblages. On the basis of the same
similarity matrix, samples are ordered by non-metric MultiDi-
mensional Scaling (nMDS; Figs. 5A—C; Kruskal 1977). The
nMDS is an iterative procedure to represent the “distance” of
samples from a multidimensional space on the basis of rank
dissimilarities. Clusters identified both in the dendrograms and
nMDS plots, at the same similarity level, are further investi-
gated through the Similarity and Dissimilarity Term Analyses,
to highlight the contribution of each species to the total aver-
age similarity and dissimilarity within each group and between
different groups. Species and groups accounting for the aver-
age similarity and dissimilarity in all clusters are listed in or-
der of decreasing contribution in Tables 3 to 5.
Results
Biostratigraphy
Rögl (1969) studied in detail the foraminiferal biostratigra-
phy of Laa Th. brickyard. In Hole BL 503, planktonic and
benthic foraminifers are relatively well preserved throughout
the sequence. Two levels (Samples 15.4 m and 20.9 m) yield a
completely pyritized fauna consisting of large globigerinids
(e.g. Globigerina concinna) and Globigerinella obesa group
together with Spiroloculina compressiuscula and Virgulinella
pertusa, which are not present in the remaining samples (Table
1). Bulimina elongata, Valvulineria complanata, Praeglobob-
ulimina, and Uvigerina groups peak in correspondence of the
pyritized levels (Fig. 2). These levels were previously identi-
fied from middle Karpatian sediments in Outer Carpathian ba-
sins in Moravia and termed “Virgulinella Horizons” (Vašíček
1951). Reworked specimens were identified, whenever possi-
ble, considering their different preservation, and counted sepa-
rately. Some specimens of selected benthic foraminifers (e.g.
Ammonia spp.) possibly reworked and present throughout the
sequence could not be separated as such as a result of their
preservation consistent with the accompanying assemblage
(e.g. in Samples 27.8 m and 27.5 m).
The sequence is attributed to the middle Karpatian on the
basis of the presence of the pyritized levels and on the typical
assemblage containing Uvigerina graciliformis, Pappina
Fig. 1. Paleogeographical map showing the position of Laa an der Thaya during the Karpatian.
ECOLOGY OF FORAMINIFERS AND NANNOPLANKTON: A STATISTICAL APPROACH 363
primiformis and P. breviformis in the absence of younger spe-
cies such as Globigerinoides bisphericus.
Martini & Müller (1975) studied the calcareous nannofossil
content in a few samples from the Karpatian of the Central
Paratethys. In Hole BL 503, nannofossil assemblages are rela-
tively well preserved but not rich (from 3—5 specimens/1 field
of view to 3—5 specimens/10 fields of view) throughout the
section. They are characterized by relatively abundant and
constantly present Calcidiscus leptoporus, Calcidiscus tropi-
cus, Coccolithus pelagicus, C. miopelagicus, Coronocyclus
Fig. 2. Abundance curves of selected benthic, planktonic foraminifers and calcareous nannofossil species.
364
SPEZZAFERRI
a
n
d
CORIC
Table 1: Distribution of benthic and planktonic foraminifers and calcareous nannofossils in samples from Hole 503, Laa an der Thaya.
Benthic Foraminifera 1
Met
er
s
A
delos
ina lon
gir
os
tr
a
A
labam
ina tangenz
ia
lis
A
llia
tina
c
f.
excent
ri
ca
A
llia
tina tol
lmanni
A
mmoni
a par
kins
oniana
A
mmoni
a tepida
A
mmoni
a viennens
is
A
m
phim
or
phina hauer
ian
a
A
ngul
oger
ina angulos
a
A
ster
iger
inata mamil
la
A
ster
iger
inata plan
or
bis
A
str
ononion s
telli
ger
um
A
ubig
nyna per
lucida
B
aggi
na ar
enar
ia
B
oliv
in
a dilata
ta
gr
.
B
oliv
in
a dilata
ta max
ima
B
oliv
in
a fas
tigia
B
olivin
a hebes
B
olivin
a kor
ynoides
s
ubtumida
B
oliv
in
a plic
ate
ll
a
B
olivin
a pokor
nyi
B
oliv
in
a s
agittula
B
ulim
ina elongat
a
gr
.
C
as
si
dulina car
inata
C
as
si
dulinoides
oblong
a
C
aucas
ina s
chis
chkins
kayae
C
aucas
ina s
ubulata
C
hilos
tome
lla ool
ina
C
hilos
tomella ovoi
dea
C
ibicides
tenellus
C
ibicidoides
cf
. aus
tr
iac
us
C
ibicidoides
lopja
nicus
C
yclofor
ina
cf
. contor
ta
C
yc
lofor
ina gr
ac
ilis
Dentalina bouea
na
E
lphi
diella heter
opor
a
E
lphi
diella min
uta
E
lphi
diella s
emincis
a
E
lphi
diella
sp
.
E
lphi
diella s
ubnod
os
a
E
lphi
dium angu
latum
E
lphi
dium
cf
. lis
te
ri
E
lphi
dium fichetel
ianum
E
lphi
dium macellum
E
lphi
dium matz
enens
e
E
lphi
dium r
eus
si
E
lphi
dium r
ugos
um
E
lphi
dium
sp
.
E
lphi
dium s
ubtypicum
E
lphi
dium unger
i
E
scor
nebovina ? tr
ochifor
m
is
F
is
su
ri
na laevigata
F
issu
ri
na
m
arg
in
at
a
F
is
su
ri
na or
bignyana
F
ur
se
nkoina acuta
Glabr
ate
llin
a aur
antis
ta
Glabr
ate
llin
a pate
llif
or
mis
Globocas
si
dulin
a globos
a
Globocas
si
dulin
a oblonga
5.5–5.6
1 1 1 12 50 86
1
18
5
1
1 5 1 2 17
3
4
1 2
1
1
1 1 3
1 4
7.6–7.7
2
19
6
1
1
1
1
1
1
9.1–9.2
5 1 9
1 1 1
7 19 16
1
1
18 4
1
8
1 2cf
1
1cf 1
1
10.8–10.9
8
8 16 55
1 42
2 1
1
1
1
1cf
1 1
13.2–13.3
3
2
1
7
1
2
1
3
1
1
2
15.4–15.5
2
1
3 2 1
6
2
2 4
1
1
1
3
1
17.6–17.7
2
3
16 2
1 1 2 1
1
4
6
2 1
3
2
1cf
20.9–21
5
1
1
12
4
94
1
1 13
1
1
22.4–22.5
3 1
4 16 1 1
3 14
12
10
27
9 4
5
3
3
3
23.4–23.5
3 16 2
3 2
6
9
62
6 8
5
2
1 1
1
25.6–25.7
1
7
12 3
5
5
41
5 4
1
1
2
1
27.8–27.9
2
1 4 2 15
1
5 4 27
2
1
15 1
2 8 6
1
1cf
1 1 1
2
2 1
29.5–29.6
1
8 25
6
2cf 1
2
1cf
3
1
Benthic Foraminifera 2
Met
er
s
Globulin
a gibba
Gr
ige
lis
py
ru
la
Hans
enis
ca s
oldanii
Gyr
oidinoides
laevigatus
Gyr
oidinoides
umbona
tus
Hanz
avaia boueana
Heter
olepa dutemplei
Lagena clavata
Lagena his
pida
Lagena is
abella
Lagena laevis
Lagena s
emis
tr
iata
Lenticuli
na calcar
Lenticuli
na gibba
Lenticuli
na inor
nata
Le
ntic
uli
na me
lv
illi
Lenticuli
na or
bicular
is
Lobatu
la lobatu
la
M
elonis
pompi
lioides
Milio
lids
sp
.
N
eoeponides
br
adyi
N
odos
ar
ia longis
cata
N
onion commune
N
onionella
cf
. s
te
lla
N
onionella
sp
.
Or
idor
sa
lis
umbonatus
P
appi
na br
evifor
m
is
P
appi
na pr
imifor
m
is
P
appi
na
sp
.
P
ar
ar
otali
a aculeata
P
lanu
lar
ia mor
avica
P
lectofr
ond
icular
ia digi
talis
P
lectofr
ond
icular
ia inaeq
ualis
P
lectofr
ond
icular
ia r
ar
icos
ta
P
or
os
ononio
n gr
anos
um
P
or
os
ononio
n
sp
.
P
raeglobob
ulimi
na pupoides
P
raeglobob
ulimi
na pyr
ula
P
rotelphi
dium r
oemer
i
P
seu
donodos
ar
ia aequ
alis
P
ulleni
a bulloi
des
P
yr
go
ju
ve
n.
Quinquelocu
lina buchia
na
Quinquelocu
lina tr
iangu
lar
is
R
eus
se
lla s
pinulos
a
R
imin
ops
is
boueanum
R
os
alina s
emipor
at
a
Semivulvulina pecti
nata
Sigmoili
nita tenuis
Siphonod
os
ar
ia ver
neuili
Sphaer
oidina bul
loides
Spir
oloculin
a badenens
is
Spir
oloculin
a canalicula
ta
Sp
iro
lo
cu
lin
a co
m
pressi
us
cu
la
Spi
rol
ocul
in
a excavat
a
Spir
or
utilus
c
ar
inatus
Stilos
tome
ll
a adolphi
na
Stilos
tome
ll
a adv
en
a
Stilos
tome
ll
a c
ons
or
bina
5.5–5.6
2
1
1
1
1 1
3
20
17 4
42
2
1
1
4
7.6–7.7
1
1
3
3
1
9.1–9.2
1 1
3
5 1
1
2 1
8 1
392
2 1
1 2cf 1
3
2
1
10.8–10.9
5 1 8
2 1cf
2
9
176 3
1
5
2
1
13.2–13.3
1
7
1
1
1
1
1
15.4–15.5
1
9 2
1 4
11
2
1
7 1
6
1
1 2
4
17.6–17.7
3 9
2
2
2
4
103 2
1
3
1
1 3
1
2 3 1
1
3
20.9–21
1 2 3
1
3
1 11 11 2 4 3 4 6
1
1 1
23 68
1
2
1
2
4
22.4–22.5
2 18 1
20 2
1
18
15 4
1
3 1
6 12
1
1
1
1
7
2 1
3
2
23.4–23.5
1
1 7 2
1
1
4 1 1
20
15 1 6
2
1
1 2
1 1
2
5
4
1 3
1
25.6–25.7
1 2 2 12
1cf
4
8
13 4 2
1 1 2
3
2
3 1 2
2
2 1
1
27.8–27.9
5
1
10 1
2
9
41
1
6
1 1
1
6
5 2
1
29.5–29.6
7
1
3
ECOLOGY
OF
FORAMINIFERS
AND
NANNOPLANKTON:
A
STATISTICAL
APPROA
C
H
3
6
5
Calcareous Nannoplankton
Sa
mp
le
s
B
raar
udos
phaer
a bigelo
w
ii
C
alcidis
cus
leptopor
us
Cal
ci
di
scus maci
nt
yrei
C
alc
idis
cu
s pr
em
ac
inty
re
i
C
alc
idis
cu
s tr
opic
us
C
occolithus
miopelag
icus
C
occolithus
pelagicus
Coronocycl
us ni
te
scens
C
yclicar
golithus
flor
idan
us
C
ycloper
folithus
car
lae
D
isco
as
te
r
spp.
Ge
minilit
he
lla r
otula
Hay
ella
sp
.
Helicos
phaer
a ampliaper
ta
Helicos
phaer
a car
ter
i
Helicos
phaer
a euphr
atis
Helicos
phaer
a inter
m
edia
Helicos
phaer
a mediter
ranea
Helicos
phaer
a obliqua
Helicos
phaer
a paleocar
ter
i
Helicos
phaer
a s
cis
su
ra
Helicos
phaer
a
sp
.
Helicos
phaer
a w
al
ber
sdor
fens
is
Or
thor
habdus
s
er
ra
tus
P
ontos
ph
aer
a
spp.
R
etic
ulo
fe
ne
str
a ampliumbi
lic
us
R
eticulo
fenes
tr
a haqii
R
eticulo
fenes
tr
a minuta
R
etic
ulo
fe
ne
str
a ps
eudoumbilic
us
5–7
R
etic
ulo
fe
ne
str
a ps
eudoumbilic
us
>7
R
etic
ulo
fe
ne
str
a
sp
.
R
habdos
phaer
a
sp
.
Sphenolit
hus
heter
omor
phus
Sphenolit
hus
mor
ifor
m
is
Sphenolit
hus
sp
.
Syr
acos
phaer
a pulchr
a
Te
tr
alitho
ide
s s
yme
onide
si
i
Thor
acos
phaer
a heimii
Thor
acos
phaer
a s
axea
Thor
acos
phaer
a
sp
.
Tr
iquetr
or
habdul
us
milo
w
ii
Umbilic
os
phae
ra
jafar
ii
Rewor
ked S
pec
im
en
s
5.5
13 2
9 1 40 3 13 1
1
1
2
1
1
1
2
1 26 35
7 3
5
2 3
4
1
1
6
5
1
9
147
6.6
7 2
10 1 22 2 14
1
1
1
23 81 15 4
1
2
6 1
1
3 2
124
7.6
12
1 11 3 44 4 7 1
2
1
2
4
16 41 13 6
7
1
2 1 3
1
4
3 5 2 2
165
9.1
1 10
5 2 55 1 9 1
1
2
2 18 1
1
4
1
1
7
18 27 8 7
3
2
1 2 2
1
5
143
10.8
1 10 1
1 1 1 51 1 4
1
1 4
1
17 49 9 7
4
1
3 3
1
3 15 4 6
135
13.2
1 16 1
11 3 57
20 2
3
1 5
1
2
1
12 17 17 8
4
1
2
1
3
1 5 5
162
15.4
12
2 17
54
12 1
1
5
1 2 1
1
3
1 15 30 8 8
2
1
1
4
5
2 3 8
112
17.6
12
1
1 63 5
6 1
4 27
7
3
4
1
4
1 14 19 10 3
2
1
1
3
1
6
77
18.7
15 1
13 1 39 2 14
2
3
1
2
5
1 18 29 7 8
5
1 11
1
1
2 7 11
115
20.9
1 9 1
1 6 1 74 2 13 1
3
3
1 4 1
1
1
13 9 10 10
6
2
7
2
1 1 4 11
143
22.4
13 1
7
59 1 11 1
1
1 2
3
5
22 23 13 5
5
7
2
3
3 3 9
96
23.4
1 14 1
2 6 1 76 3 5 1
2
1
2
5
17 11 12 12
4
4
4
5 11
77
25.6
1 6
1 8 2 69 1 11 1
1
5
1
2
6
21 33 6 3
2
1 2
7
1
2 2 5
155
27.8
1 12
1 13 3 54 4 12 1
1
2
2
1
1
1
2
3
19 18 14 5
5
1
2
2
1
2 12
4
127
29.5
13
2 18 4 60 3
8 2
3
2
1
1
1 17 10
6 7
5
11 1
1
1
4
3 12
5
118
Benthic Foraminifera 3
Met
er
s
Stilos
tome
ll
a s
cabr
a
Stilos
tome
ll
a s
pine
sc
en
s
Textular
ia
cf
. candeiana
Text
ul
ari
a l
aevi
ga
ta
Textular
ia pala
Tr
iloculin
a gibba
Tr
iloculin
a neudor
fens
is
Uviger
ina acuminata
Uv
ige
rina gr
ac
ilifor
m
is
Uv
ige
rina par
vifor
m
is
Uviger
ina pygmoides
V
alvuli
ner
a complanata
V
ir
guline
lla per
tus
a
V
ir
gulops
is
tuber
culat
us
T
ota
l be
nt
hi
c
5.5–5.6
13
3
8
2
351
7.6–7.7
2
1
1
1
50
9.1–9.2
12
16
551
10.8–10.9
3
5
7
1
1 372
13.2–13.3
6
1
44
15.4–15.5
54
26
2 165
17.6–17.7
1
1
197
20.9–21
2
1 79 21
393
22.4–22.5
27 13
276
560
23.4–23.5
1
2
1
1
1
5
2
1 236
460
25.6–25.7
2
130
292
27.8–27.9
1
5
5
4 208
29.5–29.6
3
1
1
1
67
Planktonic Foraminifera
Met
er
s
B
eel
la
cl
avacel
la
C
as
si
ger
inella globulos
a
Globoqua
dr
ina lar
m
eui
P
ar
aglob
or
otalia acr
os
toma
Globiger
ina dip
los
toma
Globige
ri
na bol
lii le
ntia
na
gr
.
Globiger
ina bul
loides
Globiger
ina
cf
. concinna
Globiger
ina concinn
a
Globiger
ina pr
aebull
oides
gr
.
Globiger
ina r
egular
is
Globiger
ina tar
chanens
is
"G
lobi
ger
ina
" dubi
a
"G
lobi
ger
ina
" ott
nangiens
is
Globiger
inell
a obes
a
gr
.
Globiger
inell
a s
iphonifer
a
Globiger
init
a glutina
ta
Globige
ri
nit
a juv
en
ilis
Globiger
inoi
des
tr
ilobus
P
ar
aglob
or
otalia in
aequiconica
N
ot
id
en
ti
fi
ed
Tenuitell
inata ang
us
tiumbi
licata
Tur
bor
otali
ta
af
f.
quinquel
oba
Zeaglobi
ger
ina w
oodi
T
ot
al P
la
nk
to
nic
5.5–5.6
1
33
19 8
2
3
3
69
7.6–7.7
5
7
8 1
1
4
26
9.1–9.2
1
1 27
5
159
3
1 15 32
3
10
6
1 264
10.8–10.9
1
13
50
13 7
1
3
88
13.2–13.3
1
11
3 6
1
1
5 15
2
4
49
15.4–15.5
8
4 11
7
20 56
106
17.6–17.7
1
1
16
4 12
1
4
1
40
20.9–21
1
1
1
25
4 29 15 87
3
36 109
13
324
22.4–22.5
59
13 246
1 47 268
12
646
23.4–23.5
1
75
7 198 2
1
45 191
1
3
524
25.6–25.7
50
2 143
1
37 184
1
6
423
27.8–27.9
14
3
3 27
2
17 24
1
4
1
2
2
100
29.5–29.6
1
5
12
7 2
1
2
30
Table 1: Continued
366 SPEZZAFERRI and CORIC
nitescens, Cyclicargolithus floridanus, Helicosphaera amplia-
perta, H. carteri, Pontosphaera spp., Reticulofenestra haqii,
R. minuta, R. pseudoumbilicus, together with other minor
components listed in Table 1. Reworking strongly affected this
group (up to 45 %). Clearly reworked specimens are excluded
from the statistical treatment. The occurrence of H. ampliaper-
ta and Sphenolithus heteromorphus and absence of Spheno-
lithus belemnos indicate the presence of the H. ampliaperta-S.
heteromorphus Interval Zone (MNN4a) of Fornaciari et al.
(1996) corresponding to the upper part of Zone NN4 of Marti-
ni (1971).
Ecology of foraminifers and calcareous nannoplankton
The paleoclimatic-paleoecological significance of Miocene
foraminifers and calcareous nannoplankton are deduced from
their latitudinal abundance patterns, oxygen and carbon isoto-
pic composition of tests and from comparison of these parame-
ters with those of the modern counterparts. In particular, the
paleoecological significance of benthic foraminifers is based
on Rögl (1969), Rupp (1986), DeStigter et al. (1988); Nishi
(1990), Cimerman & Langer (1991), Murray (1991), Jorissen
et al. (1992), Sgarrella & Moncharmont-Zei (1993), Kaiho
(1994), Culver et al. (1996), Gupta (1997), Bernhard et al.
(1998), Debenay et al. (1998), Basso & Spezzaferri (2000).
The paleoecology of the most relevant benthic foraminiferal
species identified at Laa Th. is shown in Table 2.
Following Spezzaferri (1995) and Rögl (pers. comm. 2001)
planktonic foraminifers were grouped according to their paleo-
climatic significance as follows: the warm water indicators are
Globoquadrina larmeui, Globigerinoides trilobus, Para-
globorotalia acrostoma; the temperate water indicators are
Globigerinella obesa, Globigerinella regularis, Globigerinel-
la siphonifera, Globigerina concinna, Paragloborotalia
inaequiconica, Zeaglobigerina woodi. The cool water indica-
tors are Globigerina praebulloides group, “Globigerina” ott-
nangiensis, “Globigerina” dubia, Globigerina bollii lentiana,
Tenuitellinata angustiumbilicata, Turborotalita quinqueloba,
Globigerinita juvenilis and Globigerinita glutinata. The abun-
dance trends of paleoclimatic indices were plotted in Fig. 3.
The paleoecological interpretation of the calcareous nanno-
plakton assemblages is more problematic because this group
of microfossils includes coccolithophorids (e.g., C. pelagicus)
and other incertae-sedis forms such as Discoaster and Heli-
cosphaera. Our paleoecological interpretation is based mainly
on variations in the relative abundances of C. pelagicus, R.
minuta, and Sphenolithus and Helicosphaera groups. Cocco-
lithus pelagicus is considered a good paleoclimatic indicator
(Haq 1977). In modern oceans it prefers cold and nutrient rich
surface waters with temperature between 7 and 14
°
C (McIn-
tyre & Be 1967). Haq & Lohmann (1976) suggested that this
species migrated from the tropics towards the poles during the
middle Cenozoic changing its ecological preference. Rahman
& Roth (1990) interpreted the relatively high abundances of C.
pelagicus as related to intense upwelling, and an unstable
stratified water column. High abundance of C. pelagicus in the
middle Miocene subtropical sediments of the Vienna Basin
point to a strong influence of nutrient availability (Fuchs &
Stradner 1977). Gartner et al. (1983/84) suggested that the size
of the coccoliths is associated with seasonal fluctuations in nu-
trients and temperature and that changes in relative abundance
of small R. minuta (<3
µ
m) can be a signal of changes in nutri-
ent dynamics. Investigations on living specimens of H. carteri
from the Atlantic Ocean (McIntyre & Be 1967; Okada &
McIntyre 1979) and Pacific Ocean (Okada & Honjo 1973)
demonstrated that this species can tolerate temperature ranges
from 5
°
C to 30
°
C (Okada & McIntyre 1979). However, it is
more common in tropical and subtropical waters. Perch-Niels-
en (1985) remarked that the Sphenolithus and Helicosphaera
groups (in particular, H. ampliaperta), most commonly occur
in hemipelagic sediments and are generally absent in pelagic
sediments. The Helicosphaera group is also interpreted as an
upwelling-preferring species (Perch-Nielsen 1985).
Statistical treatment
Since patterns of community structures are often not readily
apparent (Clark & Warwick 1994), we have performed the
statististical treatments of our data to better identify and char-
acterize changes in the assemblage structures and relate these
to changing environmental conditions.
Benthic Foraminifers: At 45% of the Bray-Curtis Similarity
3 Clusters separate (Figs. 4A, 5A). Cluster 1 groups Sample
7.6 m and 29.5 m. Six species and/or groups account for the
90.24 % of the average similarity within this group. Cluster 2
groups Samples 20.9 m, 25.6 m, 22.4 m, and 23.4 m. Seven
species and/or groups account for 80.70 % of the average simi-
larity within this group. Cluster 3 groups Samples 15.4 m, 5.5
Fig. 3. Planktonic foraminiferal climatic indicators.
ECOLOGY
OF
FORAMINIFERS
AND
NANNOPLANKTON:
A
STATISTICAL
APPROA
C
H
3
6
7
Table 2: Ecological preference of selected benthic foraminifers. Oxic, Suboxic A-C, and dysoxic indicators are as in Kaiho (1994). Terms “epipelic”, “endopelic” and “epiphytic” from Ramade (1993).
Species
Environment
Preferred depth range (m)
Preferred substratum
Living strategy
Comments
(when known)
when known
(when known)
(when known)
Ammonia beccarii/viennensis
Infralitoral, rarely
circalitoral (Inner shelf)
Down to 100 m, more abundant
0–50 m
Fine infralit. sand, detritic circal/red
algae
Epipelic or shallow endopelic
Salinity >33 ‰
Amphimorphina haueriana
Shelf
Mud-silt
Ammonia tepida
Infralitoral, rarely
circalitoral (Inner shelf)
Down to 100 m, more abundant
0–50 m
Muddy sand, sandy mud, detritic
circalitoral
Epipelic or shallow endopelic
Low salinity (<33 ‰), river mouths,
low energy
Aubignyna perlucida
Infralitoral, rarely
circalitoral (Inner shelf)
Down to 100 m, more abundant
0–50 m
Fine infralit. sand, detritic circal/red
algae
Epipelic
Salinity >33 ‰
Baggina arenaria
Shelf
Silt
Bolivina dilatata
Infralitoral-bathyal
(inner shelf to bathyal)
Abundant from 50 to 200
Mud
Shallow endopelic
Low oxygen, tolerant of low food availability
Bolivina hebes-plicatella-pokornyi gr.
Inner shelf to bathyal
(inner shelf to bathyal)
Abundant from 50 to 200
Mud
Shallow endopelic or epiphytic
Low oxygen, tolerant of low food availability
Bulimina elongata gr.
Infra-upper circalitoral
(inner shelf to bathyal)
Abundant down to 80–100 m
Mud and muddy sand
Endopelic
River mouths, high organic matter,
low oxygen
Caucasina schischkinskayae
Infra-upper circalitoral
(inner shelf to bathyal)
Abundant down to 80–100 m
Mud and muddy sand
Endopelic
River mouths, high organic matter,
low oxygen
Chilostomella ovoidea
50 down to 2000 m
Mud
Endopelic
Dysoxic
Cibicidoides lopjanicus
Shelf to bathyal
Hard substrates
Epiphytic
Oxic
Elphidium sp.
Inner shelf
0–50 m
Mud and sand
Epiphytic
Oxic
Hanzawaia boueana
Inner shelf
0–50
Hard substrates?
Epiphytic
Oxic
Lenticulina gr.
Infralitoral to bathyal
(outer shelf and bathyal)
From 20 m down
Suboxic B
Nonion commune
Shelf
0–180 m
Mud and silt
Epipelic-Endopelic
Salinity 30–35 ‰
Oridorsalis umbonatus
Usually bathyal
Usually from 600 m downward
Mud
Endopelic (3 cm and below)
River mouth, high Corg, high nutrients (upw),
Temp. down to 4 °C
Pappina sp.
Shelf
Clay-silt
Endopelic
Low oxygen, high Corg?
Porosononion granosum
Infra-circalitoral
0–100 m
Sand with Cymodocea
Low salinity, river mouths, high energy
Praeglobobulimina gr.
Circalitoral to bathyal
80–800
Dysoxic
Spiroloculina compressiuscula
Shelf
0–40
Sediment and/or algae
Clinging
May be present in lagoons
Textularia gr.
Shelf to bathyal
0–500
Hard substrates and sand?
Clinging
May be present in lagoons
Uvigerina gr.
Shelf to bathyal
100 to >4500 m, rarely shallower
than 100 m
Mud
Shallow endopelic, rarely epiphytic
Suboxic B, and high organic matter
Valvulinera sp.
Circalitoral to epibathyal
Abundant between 40–100 m
Mud
Low oxygen (dysoxic?), high organic matter
Virgulinella pertusa
Mud
Dysoxic
Epiphytic = living on algae or on seagrass
Epipelic = living in the superficial layer of sediment
Endopelic = living inside the sediments
368 SPEZZAFERRI and CORIC
m, 17.6 m, 27.8 m, 9.1 m, and 10.8 m. Twelve species and/or
groups account for 80.54 % of the average similarity within
this group.
Planktonic Foraminifers: At 65% of the Bray-Curtis Simi-
larity 3 Clusters separate (Figs. 4B, 5B). Cluster 1 groups
Samples 15.4 m and 27.8 m. Four species and/or groups ac-
count for 96.82 % of the average similarity within this group.
Cluster 2 groups Samples 9.1 m, 20.9 m, 23.4 m, 22.4 m, 25.6
m. Four species and/or groups account for 93.75 % of the aver-
age similarity within this group. Cluster 3 groups Samples 7.6
m, 29.5 m, 17.6 m, 5.5 m, 10.8 m. Five species and/or groups
account for 80.54 % of the average similarity within this
group.
Calcareous Nannofossils: At 75% of the Bray-Curtis Simi-
larity 3 Clusters separate (Figs. 4C, 5C). Cluster 1 groups
Samples 17.6 m, 9.1 m, and 25.6 m. Seven species and/or
groups account for 83.87 % of the average similarity within
Fig. 4. Hierarchical agglomerative clustering based on the Bray-
Curtis Similarity of (A) benthic foraminifers; (B) planktonic fora-
minifers; (C) calcareous nannofossils.
Fig. 5. Non-metric MultiDimensional Scaling (nMDS) plots of (A)
benthic foraminifers; (B) planktonic foraminifers; (C) calcareous
nannofossils. The order of the group in the nMDS is the order of
the same groups in the dendrograms of Fig. 6A—C. Sample posi-
tion in nMDS and dendrogram may not correspond because of the
ordination procedure in the nMDS plot. The stress represents the
distortion involved in compressing the data from a multidimen-
sional space into a smaller number of dimensions.
ECOLOGY OF FORAMINIFERS AND NANNOPLANKTON: A STATISTICAL APPROACH 369
Fig. 6. Plankton/Benthos Ratio (100 P/(P+B), and interpretation of
paleodepth plotted vs. the simplified lithology of Hole BL 503. P =
planktonic foraminifers, B = benthic foraminifers.
this group. Cluster 2 groups Samples 10.8 m, 20.9 m, and 23.4 m.
Eight species and/or groups account for 81.92 % of the aver-
age similarity within this group. Cluster 3 groups Samples
29.5 m, 7.6 m, 27.8 m, 5.5 m, 22.4 m, 13.3 m, and 15.4 m.
Eight species and/or groups account for 81.12 % of the aver-
age similarity within this group.
Discussion
Benthic and planktonic foraminifers and calcareous nanno-
plankton can provide important information not only con-
cerning biostratigraphy, but can be used also as proxies and
tracers of the water mass to reconstruct ancient paleoenvi-
ronments.
Paleobathymetry
An approximate water depth for the Laa Formation is as-
sessed through the Plankton/Benthos Ratio, 100 P/(P+B) (Fig.
6). According to Murray (1976) we identify an inner shelf en-
vironment (values not exceeding 20 %), a middle shelf envi-
ronment (values 20—40 %) and an outer shelf environment
(values 40—60 %). Comparing the preferred depth distribution
of living benthic foraminifers (Table 2, and data in the litera-
ture) we assume a water depth between 100 and 200 m for the
sediment deposited at Laa Th. The shallower water depth ob-
served in Fig. 6 and corresponding to Samples 10.8 and 17.6
may be due to reworking and/or re-deposition of shallower
water species. The fine-sandy sediments from the top of the
section down to about 8 m (Fig. 2) correlate with the shallow-
water deposit observed by Rögl (pers. comm.) outside the
Wienerberger brickyard and therefore, sediments from Laa Th.
represent a shallowing upward sequence as also indicated by
the 100 P/(P+B) of Figure 6.
The distribution of calcareous nannoplankton supports our
bathymetric reconstruction. The Helicosphaera group is inter-
preted in the literature as “near shore” species (Perch-Nielsen
1985). Its trend in Figure 2 shows increased abundances in
correspondence of the samples recording the shallower benthic
foraminiferal assemblage and the lowest values of the 100 P/
(P+B) at 10.8 m and 17.6 m.
Paleoclimatology
Planktonic foraminifers are used to reconstruct the paleocli-
matic trend during the investigated part of the Karpatian. The
climatic trend deduced from the curve in Figure 7 suggests
that cool conditions prevailed during the investigated interval.
The coolest conditions are recorded in the upper part of the se-
quence (from Sample 10.8 m upward). The trend is interrupted
by a relatively warmer/temperate episode in its upper middle
part (Samples 13.2 and 15.4 m). Increasing abundance of R.
minuta also indicates climatic stress from the bottom to the
top of the section (Fig. 2; Rahman & Roth 1990). Absence of
warm water taxa such as Discoaster group and low abun-
dance of S. heteromorphus also implies cool surface waters
in the Paratethys during the investigated interval (Zone
MNN 4a p.p.).
Paleoenvironmental reconstruction
a – Benthic Foraminifers: Comparison between Similari-
ty and Dissimilarity Term Analyses of benthic foraminifers
and their ecological preference (Table 2 to 5, Fig. 5A) suggests
that Cluster 1 groups samples containing the shallower, rela-
tively more oxygenated, and higher salinity assemblages (Am-
monia spp., Aubignyna perlucida, Porosononion gr.). Ammo-
nia tepida and Porosononion are known in the literature to be
high salinity-tolerant species, abundant in the inner neritic en-
vironment with water depth not exceeding 50—100 m (e.g.,
Basso & Spezzaferri 2000). Cluster 2 groups samples contain-
370 SPEZZAFERRI and CORIC
Cluster 1
Average similarity = 44.59
Average dissimilarity = 80.42
Avg. Ab. Avg. Sim. Contrib.% Cum%
Group 3 Group 1
A. viennensis
22.00
32.48
46.34
46.34
Avg. Ab. Avg. Ab. Avg. Dis. Contrib.% Cum%
A. perlucida
6.00
10.26
14.63
60.98
Pappina gr.
123.33
0.50
27.7
35.08
35.08
Textularia gr.
3.50
5.13
7.32
68.29
A. viennensis
22.50
22.00
5.88
7.43
42.51
N. commune
5.00
5.13
7.32
75.61
Uvigerina gr.
14.00
0.50
5.09
6.44
48.95
Porosononion gr.
3.00
5.13
7.32
82.93
B. dilatata-sagittula-fastigia gr.
17.67
0.00
4.60
5.81
54.75
A. tepida
5.50
5.13
7.32
90.24
C. schischkinskayae
15.33
1.50
3.68
4.66
59.41
A. tepida
8.83
5.50
3.12
3.95
63.36
Cluster 2
Average similarity = 57.28
V. complanata
9.33
1.00
2.86
3.61
66.97
Avg. Ab. Avg. Sim. Contrib.% Cum%
Miliolids
7.00
0.00
2.84
3.58
70.55
V. complanata
180.25
28.23
49.29
49.29
Porosononion gr.
9.17
3.00
2.08
2.63
73.19
B. elongata gr.
56.00
9.12
15.92
65.21
Lenticulina gr.
4.67
0.00
1.78
2.25
75.43
N. commune
14.25
2.46
4.29
69.50
N. commune
10.17
5.00
1.69
2.13
77.56
O. umbonatus
11.75
2.06
3.60
73.10
B. arenaria
7.00
0.00
1.59
2.01
79.58
A. haueriana
11.00
1.72
3.00
76.10
S. pectinata
3.83
0.00
1.28
1.62
81.20
H. boueana
10.00
1.38
2.40
78.51
Average dissimilarity = 81.45
Pappina gr.
7.50
1.26
2.20
80.70
Group 3 Group 2
Avg. Ab. Avg. Ab. Avg. Dis. Contrib.% Cum%
Cluster 3
Average similarity = 34.82
V. complanata
9.33
180.25
23.21
28.49
28.49
Avg. Ab. Avg. Sim. Contrib.% Cum%
Pappina gr.
3.33
7.50
14.23
17.47
45.97
Pappina gr.
123.33
11.84
34.00
34.00
B. elongata gr.
2.00
56.00
7.81
9.58
55.55
N. commune
10.17
2.47
7.08
41.08
Praeglobobulimina gr.
0.67
28.75
4.03
4.95
60.50
A. viennesis
22.50
2.45
7.04
48.12
A. viennensis
2.50
1.75
2.92
3.58
64.08
C. schischkinskayae
15.33
1.78
5.11
53.23
Uvigerina gr.
4.00
13.25
2.42
2.97
67.05
B. dilatata-sagittula-fastigia gr.
17.67
1.70
4.88
58.12
B. dilatata-sagittula-fastigia gr.
7.67
6.00
2.11
2.59
69.64
Uvigerina gr.
14.00
1.33
3.82
61.94
C. schischkinskayae
5.33
5.25
1.81
2.23
71.87
Miliolid gr.
7.00
1.26
3.61
65.54
O. umbonatus
0.00
11.75
1.66
2.03
73.90
A. perlucida
7.17
1.25
3.60
69.14
A. haueriana
0.33
11.00
1.44
1.77
75.67
V. complanata
9.33
1.11
3.19
72.33
A. tepida
8.83
0.00
1.16
1.43
77.10
C. lopjanicus
4.83
1.03
2.95
75.28
H. boueana
1.67
10.00
1.16
1.42
78.52
S. pectinata
3.83
0.93
2.67
77.95
Porosononion gr.
9.17
1.00
1.16
1.42
79.94
Elphidium gr.
4.00
0.90
2.59
80.54
Average dissimilarity = 92.25
Group 1 Group 2
Avg. Ab. Avg. Ab. Avg. Dis. Contrib.% Cum%
V. complanata
1.00
180.25
35.95
38.90
38.90
B. elongata gr.
0.50
56.00
12.11
13.10
52.00
Praeglobobulimina gr.
0.00
28.75
6.14
6.64
58.64
A. viennesis
22.00
1.75
4.42
4.79
63.43
O. umbonatus
0.00
11.75
2.48
2.68
66.11
Uvigerina gr.
0.50
13.25
2.20
2.38
68.49
A. haueriana
0.00
11.00
2.19
2.37
70.86
H. boueana
0.50
10.00
1.98
2.14
73.00
N. commune
5.00
14.25
1.80
1.95
74.95
Lenticulina gr.
0.00
9.25
1.75
1.89
76.84
Pappina gr.
0.50
7.50
1.54
1.67
78.51
B. hebes-plicatella-pokornyi gr.
0.00
7.00
1.42
1.53
80.05
Chilostomella gr.
0.00
6.00
1.22
1.32
81.36
B. dilatata-sagittula-fastigia gr.
0.00
6.00
1.19
1.28
82.65
A. tepida
5.50
0.00
1.17
1.27
83.92
V. pertusa
0.00
5.25
1.17
1.26
85.18
ing an almost dysoxic, high organic matter-preferring assem-
blage dominated by V. complanata, B. elongata, Praeglobobu-
limina gr. (Fig. 2, Table 2). In muddy sediments the redox
boundary normally falls within a few centimeters of the sea
floor in those environments where the overlying bottom water
is well oxygenated. Therefore, the presence of an oxygen-lim-
ited component of the fauna should not automatically indicate
bottom water dysoxia (Murray 2001). However, at Laa Th. ox-
ygen-limited components of the fauna also include species liv-
ing within 0—3 cm of sediments (e.g. Uvigerina gr. in Sample
15.4 m, Figs. 2, 5A, Table 2) indicating that dysoxia also ex-
tends into the lower part of the water column. Bulimina elon-
gata and Oridorsalis umbonatus commonly occur off shore in
front of river mouths (Sgarrella & Moncharmont-Zei 1993),
where high organic matter content may reflect fresh water in-
fluence. This cluster also contains V. complanata which indi-
cates water depth from 50 to 200 m (Rupp 1986). The pres-
ence of typical bathyal benthic forms like O. umbonatus
(Table 3) may be explained by the “telescoping effects” (Alve
1990; Sen-Gupta & Machain-Castillo 1993). Fauna typical for
deeper environments may occur at relatively shallower water
depths in marginal seas or enclosed basins controlled by eco-
logical factors like organic matter fluxes, oxygen concentra-
tion, substratum, etc. Finally, Cluster 3 groups samples con-
taining assemblages intermediate between the previous two.
The high abundance of Pappina gr., a genus related to Uviger-
ina, seems to indicate intermediate suboxic conditions here.
According to these data we can interpret the lines at the bot-
Table 3: Bray Curtis Similarity and Dissimilarity of benthic foraminifers. List of species and statistical parameters in Cluster 1—3. The
Similarity Term Analysis indicates the species responsible for the similarity among clusters. The Dissimilarity Term Analysis reveals
why a cluster differs form the others, in term of species composition. Avg.Ab. = Average abundance of single species in the groups of
samples analysed; Avg.Sim. = Average similarity; Avg.Dis. = Average dissimilarity; Contrib.% = Percentage contribution of the single
species to the total similarity; Cum% = summary of the percentage contribution of the single species.
ECOLOGY OF FORAMINIFERS AND NANNOPLANKTON: A STATISTICAL APPROACH 371
tom of the nMDS plot (Fig. 5A) as the oxygenation and the
water depth gradients respectively.
b – Planktonic Foraminifers: The Similarity and Dissim-
ilarity Term Analyses of planktonic foraminifers (Table 4)
suggest that Cluster 1 groups samples containing a relatively
temperate assemblage with the highest abundance of G. obesa
(temperate-water indicator) recorded in the sequence (contri-
bution to the total similarity of 44.38 %). Cluster 2 groups
samples containing an intermediate assemblage with G. obesa
contributing to the total similarity for the 40 % and G. concin-
na contributing for the 3.5 %. Cluster 3 groups samples con-
taining the coolest assemblage and low abundance of G. obe-
sa. According to these data we can interpret the line at the left
hand side of the nMDS to be the temperature gradient (Fig.
5B).
c – Calcareous Nannoplankton: The Similarity and Dis-
similarity Term Analyses of calcareous nannoplankton (Table
5) suggest that Cluster 1 groups samples containing high nutri-
ent and coastal assemblages characterized by the C. pelagicus,
R. minuta, and Helicosphaera groups. Cluster 2 groups sam-
ples containing assemblages with characteristics intermediate
between Cluster 1 and 3 with C. pelagicus and R. minuta con-
tributing about 45 % to the total similarity. Cluster 3 groups
samples containing a relatively more pelagic assemblages.
Coccolithus pelagicus and R. minuta contribute for about the
42.4 % to the total similarity. According to these data we can
Cluster 1
Average similarity = 58.84
Avg. Ab.
Avg. Sim.
Contrib. %
Cum %
G. praebulloides gr.
168.40
30.55
44.38
44.38
G. obesa gr.
156.80
21.85
31.75
76.12
G. bollii lentiana
47.20
7.69
11.16
87.29
"G." ottnangiensis gr.
36.40
6.56
9.53
96.82
Cluster 2
Average similarity = 57.28
Avg. Ab.
Avg. Sim.
Contrib. %
Cum %
G. obesa gr.
40.00
23.30
37.50
37.50
"G." ottnangiensis gr.
18.50
16.50
26.56
64.06
G. praebulloides gr.
20.50
10.68
17.19
81.25
G. bollii lentiana
11.00
7.77
12.50
93.75
Cluster 3
Average similarity = 52.14
Avg. Ab.
Avg. Sim.
Contrib. %
Cum %
G. praebulloides gr.
23.80
25.19
44.95
44.95
"G." ottnangiensis gr.
10.20
13.56
24.20
69.15
G. obesa gr.
6.00
5.81
10.38
79.52
T. angustiumbilicata
3.20
5.80
10.35
89.87
G. bollii lentiana
4.80
4.05
7.23
97.10
Average dissimilarity = 79.77
Group 3
Group 1
Avg. Ab.
Avg. Ab.
Avg. Dis.
Contrib. %
Cum %
G. praebulloides gr.
23.80
168.40
30.26
37.93
37.93
G. obesa gr.
6.00
156.80
28.71
35.99
73.92
G. bollii lentiana
4.80
47.20
8.44
10.59
84.50
"G." ottnangiensis gr.
10.20
36.40
5.31
6.65
91.15
Average dissimilarity = 54.41
Group 3
Group 2
Avg. Ab.
Avg. Ab.
Avg. Dis.
Contrib. %
Cum %
G. obesa gr.
6.00
40.00
22.65
41.62
41.62
G. praebulloides gr.
23.80
20.50
9.43
17.34
58.96
"G." ottnangiensis gr.
10.20
18.50
6.12
11.25
70.21
G. bollii lentiana
4.80
11.00
4.88
8.97
79.19
G. regularis
0.00
4.00
2.63
4.83
84.01
G. concinna gr.
0.00
3.50
2.33
4.28
88.29
T. angustiumbilicata
3.20
0.00
2.14
3.94
92.23
Average dissimilarity = 64.37
Group 1
Group 2
Avg. Ab.
Avg. Ab.
Avg. Dis.
Contrib.%
Cum%
G. praebulloides gr.
168.40
20.50
27.44
42.63
42.63
G. obesa gr.
156.80
40.00
20.48
31.82
74.45
G. bollii lentiana
47.20
11.00
6.33
9.83
84.28
"G." ottnangiensis gr.
36.40
18.50
3.29
5.11
89.39
G. concinna gr.
13.20
3.50
2.51
3.90
93.29
Table 4: Bray Curtis Similarity and Dissimilarity of planktonic foraminifers. List of species and statistical parameters in Cluster 1—3.
372 SPEZZAFERRI and CORIC
Cluster 1
Average similarity = 77.50
Average dissimilarity = 26.57
Avg. Ab. Avg. Sim. Contrib.% Cum%
Group 3 Group 1
C. pelagicus
62.33
28.83
37.20
37.20
Avg. Ab. Avg. Ab. Avg. Dis. Contrib.% Cum%
R. minuta
26.33
10.83
13.98
51.18
Helicosphaera gr.
4.43
26.67
5.58
20.98
20.98
R. haqii
17.67
7.67
9.89
61.08
C. pelagicus
52.57
62.33
2.70
10.16
31.14
Helicosphaera gr.
26.67
7.17
9.25
70.32
R. minuta
24.86
26.33
2.46
9.26
40.40
C. leptoporus
9.33
3.67
4.73
75.05
C. tropicus
12.29
4.33
2.01
7.56
47.96
C. floridanus
8.67
3.50
4.52
79.57
R. haqii
18.14
17.67
1.07
4.03
51.99
R. pseudoumbilicus 5–7 µm
8.00
3.33
4.30
83.87
R. pseudoumbilicus 5–7 µm
11.14
8.00
1.07
4.03
56.02
C. floridanus
11.86
8.67
1.04
3.90
59.91
Cluster 2
Average similarity = 74.57
Sphenolithus gr.
5.43
3.67
0.94
3.53
63.45
Avg. Ab. Avg. Sim. Contrib.% Cum%
C. leptoporus
13.00
9.33
0.92
3.45
66.89
C. pelagicus
67.00
29.33
39.29
39.29
T. milowii
3.71
0.67
0.83
3.13
70.03
R. haqii
15.67
7.17
9.60
48.88
Pontosphaera spp.
2.71
5.67
0.76
2.86
72.89
R. minuta
23.00
4.83
6.47
55.36
Thoracosphaera sp.
4.29
1.33
0.76
2.86
75.75
R. pseudoumbilicus 5–7 µm
10.33
4.67
6.25
61.61
T. heimii
3.00
0.00
0.75
2.82
78.57
C. leptoporus
11.00
4.67
6.25
67.86
S. pulchra
2.29
3.33
0.69
2.60
81.16
R. pseudoumbilicus >7 µm
9.67
4.00
5.36
73.21
U. jafarii
9.33
3.83
5.13
78.35
Average dissimilarity = 26.20
Helicosphaera gr.
6.33
2.67
3.57
81.92
Group 3 Group 2
Avg. Ab. Avg. Ab. Avg. Dis. Contrib.% Cum%
Cluster 3
Average similarity = 78.00
R. minuta
24.86
23.00
4.51
17.21
17.21
Avg. Ab. Avg. Sim. Contrib.% Cum%
C. pelagicus
52.57
67.00
4.29
16.39
33.59
C. pelagicus
52.57
24.02
30.79
30.79
C. tropicus
12.29
4.33
1.99
7.58
41.17
R. minuta
24.86
9.06
11.61
42.40
Thoracosphaera sp.
4.29
5.33
1.52
5.81
46.98
R. haqii
18.14
7.65
9.81
52.21
C. floridanus
11.86
7.33
1.49
5.68
52.66
C. leptoporus
13.00
6.13
7.86
60.07
R. haqii
18.14
15.67
1.02
3.91
56.56
C. tropicus
12.29
4.92
6.30
66.37
U. jafarii
6.00
9.33
1.02
3.90
60.47
C. floridanus
11.86
4.73
6.06
72.44
R. pseudoumbilicus >7 µm
6.00
9.67
0.96
3.68
64.14
R. pseudoumbilicus 5–7 µm
11.14
4.33
5.55
77.98
R. pseudoumbilicus 5–7 µm
11.14
10.33
0.92
3.50
67.64
R. pseudoumbilicus >7 µm
6.00
2.45
3.14
81.12
Sphenolithus gr.
5.43
6.00
0.88
3.36
71.00
T. milowii
3.71
4.33
0.75
2.86
73.86
C. leptoporus
13.00
11.00
0.71
2.72
76.58
Helicosphaera gr.
4.43
6.33
0.69
2.63
79.21
Pontosphaera spp.
2.71
1.67
0.64
2.45
81.66
Average dissimilarity = 27.56
Group 1 Group 2
Avg. Ab. Avg. Ab. Avg. Dis. Contrib.% Cum%
Helicosphaera gr.
26.67
6.33
5.08
18.45
18.45
R. minuta
26.33
23.00
4.61
16.73
35.18
C. pelagicus
62.33
67.00
3.06
11.09
46.27
R. pseudoumbilicus >7 µm
4.33
9.67
1.33
4.84
51.11
Thoracosphaera sp.
1.33
5.33
1.28
4.64
55.75
C. floridanus
8.67
7.33
1.06
3.83
59.58
Pontosphaera spp.
5.67
1.67
1.06
3.83
63.41
U. jafarii
5.33
9.33
1.00
3.63
67.04
T. milowii
0.67
4.33
0.92
3.33
70.36
R. haqii
17.67
15.67
0.83
3.02
73.39
C. tropicus
4.33
4.33
0.83
3.02
76.41
Sphenolithus gr.
3.67
6.00
0.81
2.92
79.33
S. pulchra
3.33
1.33
0.78
2.82
82.16
Table 5: Bray Curtis Similarity and Dissimilarity of calcareous nannofossils. List of species and statistical parameters in Cluster 1—3.
interpret the line at the left side of the nMDS plot as the tem-
perature gradient and the line at the bottom of the nMDS plot
as the distance from the coast (Fig. 5C). Coccolithus pelagicus
and R. minuta, are interpreted as high nutrient indicators. Their
abundance curves show a vicariant trend (Fig. 2) and there-
fore, we suggest that high availability of nutrients character-
ized the entire studied interval.
Comparing the nMDS plots of the investigated microfossil
groups and the abundance curves in Figure 2 and 7 we observe
good correspondence of ecological factors. For example, sam-
ple 13.2 and 15.4 record the warmest assemblages and sample
10.8 one of the cooler assemblage in the three nMDS plots
(Fig. 5A—C). The distance from the coast gradient (Fig. 5C)
does not necessarily match the water depth gradient (Fig. 5A).
Shallow waters can, infact, extend very far from the coast (as
in the Adriatic Sea).
Conclusion
Our data indicate that the sediments drilled at Laa Th.
were deposited in a water depth not exceeding 200 m, rela-
tively “near shore” in an environment characterized by a gen-
erally high concentration of organic matter, suboxic to dys-
oxic conditions, high nutrient availability and variable
salinity. Generally cool conditions prevailed throughout the
investigated interval with a temperate episode in its middle
part.
We speculate that high nutrient availability possibly relat-
ed to the presence of river mouths, or alternatively to coastal
and wind-related upwelling of cool water, induced high pro-
ductivity at the surface and high accumulation of organic
matter at the bottom. Oxygen depletion probably account for
an increased bacterial activity in reducing microenviron-
ECOLOGY OF FORAMINIFERS AND NANNOPLANKTON: A STATISTICAL APPROACH 373
ments with consequent pyritization of microfossils in the two
levels at 15.4 and 20.9 m. We also suggest that nutrient avail-
ability and upwelling conditions, rather than other ecological
factors, control the distribution of calcareous nannoplankton
in the Molasse Basin.
Finally deposition near the coast and relatively shallow
water depth resulted in high percentages of reworked (Paleo-
gene and Cretaceous) nannofossil forms (up to 45 %).
Acknowledgments: This study is part of project P 13743-
Bio focused on the paleoecology of the Austrian marine Mi-
ocene. We warmly thank Christian Rupp of the Geological
Survey of Austria for providing samples from Hole 503. A
special thanks to Fred Rögl for his suggestions and advice
about taxonomy and ecology of microfossils.
Fig. 7. Climatic curve based on planktonic foraminifers. The curve
is derived from the algebraic sum of percentage abundance of tem-
perate (positive) and cool (negative) indices as proposed by Cita et
al. (1977) and successively applied by Spezzaferri & Premoli Sil-
va (1991) and Spezzaferri (1995). Since truly warm-water species
are rare, we consider the temperate group to be indicative of rela-
tive warming.
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