Τίτλος:
Latitudinal Differentiation among Modern Planktonic Foraminiferal
Populations of Central Mediterranean: Species-Specific Distribution
Patterns and Size Variability
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
Studies of the spatial distribution and size of modern planktonic
foraminifera are still lacking in the Mediterranean Sea. In this study,
17 core-top sediments collected from a north-south transect along the
central Mediterranean have been analyzed for planktonic foraminiferal
content, in terms of their distributional pattern and intraspecific size
variability. Among the analyzed planktonic foraminiferal species,
Globigerina bulloides and Globigerinoides ruber (w) were the most
abundant, presenting an antagonistic behavior and an overall decreasing
trend in their average size values from Adriatic to Ionian sub-basins.
Intraspecific differences have been also documented for G. ruber (w),
with the dominant sensu stricto morphotype to present generally higher
frequencies and more constant shell sizes than sensu lato. The greater
size variability of the latter is possibly related to its adaptation in
particular hydrographic conditions based on its depth habitat preference
and ecological characteristics to reach the (sub)optimum growth
conditions. The rest of the species occur in minor percentages and show
on average 11% increase with decreasing latitude characterized by
distinct species-specific size variations along the transect. Our
results show that the relationship between planktonic foraminifera shell
size and abundance or sea surface temperature are either absent or
weaker than previously reported for other regions and that in central
Mediterranean assemblages’ size may be mainly related to nutrient
availability. Besides the environmental parameters (sea surface
temperature, primary productivity, water depth, stratification), the
possible hidden cryptic diversity, still lingers to be consistently
determined, could give a better understanding of the geographic and
morphological differentiation within the Mediterranean planktonic
populations.
Συγγραφείς:
Kontakiotis, George
Efstathiou, Eirini
Zarkogiannis, Stergios D.
and Besiou, Evangelia
Antonarakou, Assimina
Περιοδικό:
Journal of Marine Science and Engineering
Λέξεις-κλειδιά:
planktonic foraminiferal biogeography; surface sediments; morphometrics;
shell size; environmental biomonitoring; ecological optimum conditions;
primary productivity; depth habitat preference; cryptic speciation;
central Mediterranean hydrodynamics
