Περίληψη:
This study presents novel findings on the drivers of the calcitic
planktonic foraminiferal and aragonitic pteropod Holocene assemblages of
the North Aegean Trough (northeastern Mediterranean), an area recording
the interaction between dynamic water masses as they exchange between
the northern and southern Mediterranean sub-basins. Both of these groups
of microorganisms are the major producers of calcium carbonate in the
ocean, and are particularly sensitive to climate and oceanographic
changes over the late Quaternary. Downcore micropaleontological data
from the gravity core AEX-15, supplemented with multivariate statistical
Q-mode cluster and principal component analyses (PCA) results, provide
significant insights on the water column dynamics during the Holocene.
Focusing on the last 10 calibrated thousands of years before the
present day (ka cal BP), our integrated study reveals that primary
productivity is the dominant factor controlling the planktonic
foraminifera distribution in the North Aegean Sea, whereas water column
stratification, and particularly the intensity of the oxygen minimum
zone, seems to be the major driver on the pteropod distribution. Besides
productivity and thermal stratification, which show the highest
explanatory power for planktonic foraminifera and pteropod communities,
respectively, though they affect both groups to a different extent,
upwelling seems to further affect both faunal groups. Overall, our
findings are consistent with those derived by published late Quaternary
eastern Mediterranean records, highlighting in parallel a useful
additional dimension on planktonic foraminiferal and pteropod ecology,
which is inextricably linked with the factors of primary productivity
and vertical stratification of the warm Holocene water column.
Συγγραφείς:
Giamali, Christina
Kontakiotis, George
Antonarakou, Assimina and
Koskeridou, Efterpi
