Relation between the foraminiferal assemblages and physical-chemical characteristics of sediment from the central and southern Adriatic sea

U ovom radu opisane su zajednice foraminifera u sedimentima jezgara uzorkovanih gravitacijskim korerom na 13 postaja iz područja srednjeg i južnog Jadrana te Šibenskog zaljeva s dubina između 38 m i 1200 m. S obzirom na sastav i abundanciju foraminiferskih vrsta definirane su dvije asocijacije. Eilohedra vitrea – Turborotalita quinqueloba asocijacija s dva biotopa, Turborotalita quinqueloba – Globocassidulina subglobosa biotop i Eilohedra vitrea biotop, te Turborotalita quinqueloba asocijacija. Sedimenti s većim udjelom sitnijih čestica bogatiji su organskom tvari i imaju manji udio epifaunalnih vrsta, a u takvim okolišima/zajednicama dominantne vrste su Eilohedra vitrea i Cassidulina laevigata. Indeksi raznolikosti konstantni su duž jezgre, a manji su u jezgrama s veće dubine mora. U sedimentima s postaja dubljih od 100 m, u istraženim poduzorcima, najbrojnija je Turborotalita quinqueloba, relativno mala planktonska vrsta, tipični predstavnik zajednice iz hladnih mora. U sedimentima srednjeg i južnog Jadrana elementi Mg, Al, Fe, Be, V, Cr, Sc, Co, Ni, Cu, Ti, Zn, Rb, Zr, Sb, Cs, Ba, Tl, Th su terigenog porijekla, a moguće je da postoji antropogeni unos Pb, Cd, Ag, Se i U u području Šibenskog zaljeva. Maseni udjeli Mn i Mo u sedimentima pod utjecajem su redoks uvjeta unutar jezgara te je raspodjela ovih elemenata duž jezgre povezana sa vertikalnim redoks profilima. Raspodjela foraminifera u srednjem i južnom Jadranu nije povezana s rapodjelom istraženih elemenata u sedimentima, a razlike u izmjerenim masenim udjelima nemaju utjecaj na sastav i raznolikost zajedniceThe present study investigated foraminiferal assemblages in sediment cores collected in the area of the Central and Southern Adriatic. Sediment samples were collected with a gravity corer, at 13 stations at sampling depths ranging from 38 m to 1200 m. Considering the composition and abundance of foraminiferal species, two associations were defined. Eilohedra vitrea – Turborotalita quinqueloba association with two biotopes, Turborotalita quinqueloba – Globocassidulina subglobosa biotope and Eilohedra vitrea biotope, and Turborotalita quinqueloba association. Fine grained sediments are associated with higher fine particle share have higher organic matter content and lower abundance of epifaunal species. Eilohedra vitrea and Cassidulina laevigata are dominant in such environments/assemblages. Diversity indices decrease with sea depth, while they remain constant across the core. Turborotalita quinqueloba, a relatively small planktonic species belonging to cold-water assemblages, prevails in sediments from studied subsamples at stations located at 100 m of water depth or deeper. Analyzed elements Mg, Al, Fe, Be, V, Cr, Sc, Co, Ni, Cu, Ti, Zn, Rb, Zr, Sb, Cs, Ba, Tl, and Th in sediment sampled in Central and Southern Adriatic Sea are most likely of terrigenous origin, whereas Pb, Cd, Ag, Se and U are most likely anthropogenically enriched in sediments in the Šibenik bay. Concentrations of Mn and Mo in sediments are influenced by redox conditions through the cores. Distribution of foraminifera in the Central and Southern Adriatic Sea is not related to concentrations and distribution of studied elements. Furthermore, changes in abundances of studied elements do not affect composition or diversities of studied foraminiferal assemblages