Calcareous nannoplankton inside coralligenous build-ups: the case of Marzamemi (SE, Sicily)

In the Mediterranean Sea, crustose coralline algae form mesophotic reefs referred to as Coralligenous. They act as a sediment trap and may be considered as a potential source of geological information. Two coralligenous build-ups collected during the project FISR “CRESCIBLUREEF” at 36 and 37 m water depth off the coast of south-eastern Sicily reveal the presence of calcareous nannoplankton/ nannofossil specimens within the sediment infilling. This novel finding reveals the occurrence of a mixed modern and reworked nannoplankton assemblage derived from marine-snow sedimentation and land weathering, respectively. The quantitative analysis of the assemblages from both build-ups shows a difference in sedimentation exposure derived from the different local environments where the build-ups were collected, highlighting the potential role of coccolithophores as a sedimentation proxy for coastal settings.