Ponomarenko, E., Krechik, V., Dorokhova, E.
Environmental factors affecting recent benthic
foraminiferal distribution in the south-eastern Baltic Sea
Santrauka The
Baltic Sea is characterized by a restricted exchange of deep waters due to
permanent stratification of the water column. The aim of the present study is
to investigate the distribution of benthic foraminifera in the south-eastern
part of the Baltic Sea in relation to environmental parameters. The
distribution of benthic foraminifera was analyzed in 26 surface sediment
samples collected in the south-eastern part of the Baltic Sea and in the
Bornholm Basin during springtime and wintertime 2016. Foraminiferal diversity
in the studied region was extremely low. Agglutinated specimens dominated the
assemblages and were represented by small-sized individuals which belong to
Psammosphaera, Pseudothurammina, Saccammina, and Reophax genera. Calcareous foraminifera
were dominated by Cribroelphidium genus. Micropaleontological data were
compared to the environmental parameters characterizing bottom water
(temperature, salinity, and dissolved oxygen content) and substrate conditions
(grain size composition and total organic carbon content). Higher foraminiferal
concentrations and diversity were found in deeper parts of the study region
where fine-grained sediments with a higher total organic carbon content were
accumulated under stable hydrographical conditions. Calcareous tests were found
only at the stations with elevated salinity, indicating that bottom water
salinity is the main factor limiting the distribution of calcareous
foraminifera. On the other hand, substrate parameters and hydrodynamic
conditions appear to play a major role in the distribution of agglutinated
foraminifera. Doi https://doi.org/10.5200/baltica.2020.1.6 Raktažodžiai North Sea water inflows; grain-size composition; total organic content; Gdansk Basin; agglutinated foraminifera
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