Recent agglutinated foraminifera from the North Adriatic Sea: What the agglutinated tests can tell

Agglutinated foraminifera from surface sediments of two sites (S1 and E1) in the North Adriatic Sea were investigated in order to detect their test composition and to explore possible links with the surrounding environment. Chemical-mineralogical analyses of the agglutinated tests by scanning Electron Microscopy and Energy Dispersive Spectroscopy, suggest that the chemical composition of the test surfaces generally mirrors the one of the sea-floor sediment. Only some species, as Reophax nana and Leptohalysis scottii exhibit a clear selectivity of the agglutinated grains. In detail, specimens of R. nana from site E1, which is mainly characterized by high hydrodynamic conditions at the sea-floor, show a preferential selection of mineral grains containing high concentrations of Zircon (Zr) and Titanium (Ti) even if these elements occur in very low concentrations in the surrounding sediment. L. scottii exclusively picks mica flakes to build the test. We suggest that the compositional differences recorded in the considered agglutinated foraminiferal tests represent distinctive life strategies in order to live successfully in different environments.