10ο Πανελλήνιο Συμπόσιο Ωκεανογραφίας & Αλιείας 7-11 Μαΐου 2012, Αθήνα Υδάτινα Συστήματα και Μέγα κλιματικές αλλαγές

1. Emiliania huxleyi COCCOLITHS IN THE
SEDIMENT RECORD AND THE RELATIVE
CLIMATIC SIGNAL: EXAMPLES FROM THE
EASTERN MEDITERRANEAN
Triantaphyllou M.V. 1
1
University of Athens, Faculty of Geology and Geoenvironment, Dept. of Historical Geology and
Paleontology, Panepistimiopolis 15784, Athens, Greece

2. Introduction
Emiliania huxleyi is by far the most abundant
and widespread coccolithophore in the world
ocean and was first identified by Lohmann
(1902) using a light microscope. The
coccolith complicated structure was first
described by the pioneers of Scanning
Electron Microscopy, distinguished three
types: (A, B and C) of E. huxleyi based on
heterococcolith morphology, demonstrating
that the size of the different morphotypes is
influenced by ecophenotypic and genotypic
factors. The phylogenetic origins of E.
huxleyi are documented in the fossil record.
The monospecific genus Emiliania is
considered to have evolved from the genus
Prinsius through Toweius , Reticulofenestra
and Gephyrocapsa .

3. Introduction
Amongst the extant coccolithophores, E.
huxleyi has the widest distribution dominating
the living assemblages. It occasionally forms
massive blooms, when water conditions are
favorable, e.g. high light, limiting silicate and
high carbonate saturation, and under certain
environmental conditions it sheds coccoliths.
The variation in E. huxleyi coccolith size and
morphology is likewise frequent, being
usually associated with temperature, salinity
and available nutrients.

4. Introduction Black Sea
The increase in atmospheric CO2 partial
pressure and the consequent changes in Athos
the seawater carbonate chemistry can Greece
SK
4
cause a decrease in E. huxleyi cellular
5
Skiros
Si gri
PIC/POC ratio as well as malformations Evoi ko s
6
of the coccoliths. Recently Sou nio
And ros
(Triantaphyllou et al., 2010)
Poros
Ionian Sea
Aegean Sea
demonstrated the morphological M19494
M20296
M3786
variability of E. huxleyi var. huxleyi (= E. 8
M2778
M1949
M940
M442
huxleyi type A) in the modern Aegean
Rh odos
Levantine
Sea, providing strong evidence for Sea
seasonal variation in E. huxleyi
coccoliths.
A consistent pattern of increase in the
size and calcification of coccoliths and
coccospheres has been observed,
including the thickness of the inner tube
elements in winter/spring time low sea
surface temperature and moderate
productivity samples when compared with

5. Introduction
100
o t h e r s p e c ie s
90
Mean relative
percentage of 80
E. huxleyi in the 70
Aegean water
lith o p h o r e s
H o lo c o c c o -
samples (5- 60
120m) during % 50
the different
40
sampling
E . h u x le y i
periods 30
20
E. huxleyi cell density:
Jan: 34x10 3 cells/l, 10
March: 23x10 3 cells/l
Aug.-Sept.: 2x10 3 0
cells/l J a n u a ry M a rc h A p ril A u g u st S e p te m b e r
Triantaphyllou et al., 2010

6. E. huxleyi coccospheres from low
temperature (Jan.- March) water
assemblages
Triantaphyllou et al., 2010
In the central area there is evidence of heavy calcification with inner tube
elements beginning to merge and lose their individual identity, leading also
to apparent fusion of the tube elements with the inner ends of the rays of the
distal shield.

7. E. huxleyi coccospheres from high
temperature (August-September) water
assemblages
Triantaphyllou et al., 2010

8. Introduction
The First Appearance
Datum (FAD) of E. hu xleyi
in the geological record is
used as a biostratigraphic
marker and marks the
base of the NN21
calcareous nannofossil
biozone (NN21a, Martini,
1971). It has been dated
at ~270 ka.
The blooming life-style of
the species started in
warm periods between ~80
ka at the end of MIS 5 and
50 ka (MIS 3) (Kroon et
al., 1998), associated with
the E. huxleyi Acme Zone
(NN21b, Martini 1971) in
the fossil record.

9. Scope of the study
A number of on land and marine core sediment
records are presented in the context of this
review, as examples considering NN21a and
NN21b biozones, including NN21a/NN21b
boundary. The detected E. huxleyi
assemblages, beyond their application as a
unique biostratigraphic tool, are used to
evaluate the paleoenvironmental and
paleoclimatic conditions prevailing in the
related time intervals.

10. Materials and Methods
The presented sediment
records represent on land
sequence at the
Aravonitsa plateau,
northern Peloponnese
(location L11, Palyvos et
al., 2009), deep sea
gravity core records
ADE3-23 Libyan Sea
(Triantaphyllou et al.,
2010b), NS-14 south-
eastern Aegean Sea
(Triantaphyllou et al.,
2009), HCMR2-22 south
Cretan margin (Ioakim et
al., 2009; Katsouras et
al., 2010) and long piston
core record LC-08,
Pantelleria Trough
(Anastasakis & Pe-Piper,
2006) .

11. Materials and Methods
The definition of E. huxleyi NN21a biozone is
based on the presence of the first
representatives of the species as the midpoint
of the slope of the initial increase of the
species in 300 specimens counts is defined as
the interval where E. huxleyi frequency values
are exceeding the 20% level (Castradori,
1993).
Specimens resembling to Reticulofenestra
spp. were assigned here as EHMC ( Emiliania
huxleyi Moderately Calcified) morphotypes,
following Crudeli et al. (2004).

12. Results and Discussion
ON LAND RECORDS
Species % W146A W146B
Micropalaeontological analyses Samples
of calcareous nannoplankton in
two samples from the fine- E. huxleyi 1 1
grained shallow marine small Reticulofenestra spp. 34 12
deposits (location L11; Palyvos Small Gephyrocapsa spp. 60 80
et al., 2009) in Aravonitsa Syracosphaera pulchra 1 1
plateau (westernmost part of Gephyrocapsa oceanica 3 2
the Corinth Gulf), yielded G. protohuxleyi 3
nannoplankton assemblages in
Calcidicus leptoporus 0.7 0.6
highly diluted terrigenous
material. Umbilicosphaera sibogae 0.3 0.4
The studied material contained abundant small Gephyrocapsa spp.
including Gephyrocapsa protohuxleyi . Small coccoliths resembling to E.
huxleyi , are very rarely present, nevertheless they bear platy distal shield
elements in contact for much of their length and do not show any trace of
hammer-heads. They have been determined as small Reticulofenestra
spp. specimens which have undergone etching resulting in separation of
the ends of the elements

13. Results and Discussion
ON LAND RECORDS
1-5. G.
protohuxleyi
6-7. small
Reticulofenestr
a
8-9. E. huxleyi

14. Results and Discussion
ON LAND RECORDS
The lowest occurrence of E.
huxleyi (at 270 ka) in the
stratigraphic record of the
eastern Mediterranean falls
within the cold MIS8, a period
of low sea-levels based on
sea-level curves (e.g.
Shackleton & Pisias, 1985;
Sidall et al., 2003). However,
during this period, the Corinth
Gulf was expectedly a lake,
isolated from the sea by a sill.
Depending on the elevation of
the sill at the time, the lowest
occurrence of E. huxleyi in the
Corinth Gulf is thus expected
more or less close to the
MIS7e highstand (i.e. a few
kyr before 240 ka), because
only then the sea water had
the chance to enter the gulf.

15. Results and Discussion
MARINE CORE RECORDS

16. Results and Discussion
MARINE CORE RECORDS
Species % LC08-3 LC08-3 LC08-3 LC08-3 LC08-3 LC08-3 LC08-3
Samples 40cm 50cm 60cm 70cm 80cm 95cm 100cm
E. huxleyi 35 29.4 5.5 7.4 3.9 2.1 6.3
G. muellerae 41.1 48.2 47.9 47.6 57.1 86.1 74.4
small Reticulofenestra spp. 11.8 5.7 38.9 39.6 31.9 8.9 16.7
Syracosphaera pulchra 3.6 6.3 1.4 2.9 2.8 2.1 0.4
Helicosphaera carteri 3.2 3.3 1.9 0.3 1.7 0.6 1.6
Calcidicus leptoporus 3.2 2.7 3.9 1.2 1.8 0.3 0.4
BIOZONE NN21b NN21a
A very clear transition from NN21a to NN21b is recorded at the lower part
of the long piston core LC 08 in Pantelleria Trough, Sicily Channel. This
part of the core is featured by the presence of a thick volcaniclastic
interval deposited from a large gravitative flow during the Green Tuff
eruption (Anastasakis & Pe-Piper, 2006). The lower hemipelagic marls,
immediately below the base of the volcaniclastic interval have been
examined for their nannofossil content. E. huxl eyi presents abundance
below 10% at the lower parts of this interval, which sharply change to
prominently high numbers above 20% upwards. Age of 41190±1090 BP
(Beta 198833) with a calibrated radiocarbon age of 43-47±2 ka

17. Results and Discussion
MARINE CORE RECORDS
1.NN21a biozone,
sample LC08-3-
100cm,
2. E. huxleyi distal,
sample LC08-3-
100cm,
3. E. huxleyi distal,
sample LC08-3-
60cm,
4. E. huxleyi
proximal, sample
LC08-3-40cm,
5. G. muellerae
coccosphere,
sample LC08-3-
60cm,
6. Helicosphaera
carteri , sample
LC08-3-60cm,
7-8. Coccolithus
pelagicus distal and
proximal, sample
LC08-3-60cm,
9. H. carteri HOL
( Syracolithus
confusus ), sample
LC08-3-60cm.

18. Results and Discussion
MARINE CORE RECORDS
1-2. E. huxleyi
Acme Zone, sample
67-68 cm,
3. G. muellerae, G.
muellerae Acme
Zone, samples 145-
146 cm, 173-174
cm, 4-8. G.
muellerae Acme
Zone, samples 118-
119cm, 145-146 cm,
173-174cm,
9. small
Reticulofenestra
spp., sample 173-
174 cm.
Samples from
gravity core
HCM2/22.

19. Conclusions
The presented sediment records reveal varied E. huxleyi
assemblages in different time intervals, nevertheless strongly
associated with climate variability during marine isotope stages
MIS 1-8.
In particular, based on E. huxleyi assemblages:
• The lowermost part of biozone NN21a has been documented with
the first representatives of the species in Aravonitsa plateau on
land samples (northern Peloponnese), which are most probably
placed at the warm MIS 7e at approx. 240 ka.
• The definition of NN21a/NN21b boundary is marked by an abrupt
increase of E. huxleyi within relatively warm MIS 3, at 50ka, in the
marine core ADE3-23 sediment record, followed by the top of the
Gephyrocapsa muellerae Acme Zone (45.7 ka). The latter event
has also been recognized at the lower part of one more sediment
record, core HCM2/22 from the south Cretan margin
• A very clear transition from NN21a to NN21b is recorded at the
lower part of the long piston core LC 08 in Pantelleria Trough,
Sicily Channel. The available AMS radiocarbon age provides
temporal calibration for the basal part of biozone NN21b in the

20. Conclusions
• E. huxleyi displays values well below 20% during the cold MIS 6
and MIS 4 in the marine core ADE3-23 sediment record, although
during the latter stage, values are comparably higher. It exceeds
slightly 10% during the warm MIS 5.
• Further increase of E. huxleyi is recorded within warm MIS 1,
whereas EHMC morphotypes are particularly present during the
cold MIS 2 in the marine core ADE3-23 sediment record. The
considerable fluctuations of E. huxleyi documented in the high
resolution marine core NS-14 record (south-eastern Aegean Sea),
reveal millennial climate variability during MIS 1 in the Late
Glacial-Holocene.