Vol.:(0123456789) 1 3 Rendiconti Lincei. Scienze Fisiche e Naturali https://doi.org/10.1007/s12210-018-0712-9 CHANGES AND CRISES IN THE MEDITERRANEAN SEA Live benthic foraminifera from the Volturno River mouth (central Tyrrhenian Sea, Italy) Luciana Ferraro 1  · Sergio Bonomo 1,2  · Ines Alberico 1  · Antonio Cascella 3  · Laura Giordano 1  · Fabrizio Lirer 1  · Mattia Vallefuoco 1 Received: 30 January 2018 / Accepted: 7 May 2018 © Accademia Nazionale dei Lincei 2018 Abstract Living benthic foraminiferal assemblages were investigated at 22 marine stations in front of the Volturno River mouth (Gulf of Gaeta, central Tyrrhenian Sea), during 3-years survey (2012–2014). The results were compared with the oceanographic data recorded at the same sites, to highlight the ecology of the main dominant species and the relationship between the com- munity structures and the environmental variables (turbidity, dissolved oxygen content, salinity, temperature, and runof). The living assemblage, analyzed in the top 1 cm of sea foor, was characterized by three dominant species (Ammonia tepida, Bulimina elongata, and Rectuvigerina phlegeri) during all the sampling periods. Correlation analysis identifed turbidity, runof, and oxygen as the main environmental factors infuencing living foraminiferal assemblages. Ammonia tepida and Rectuvigerina phlegeri showed opportunistic behaviour in response to turbidity, oxygen, and salinity values. No signifcant correlation was recorded between Bulimina elongata and the environmental parameters, testifying the capability of this species to adapt to diferent environmental conditions. The occurrence and distribution of these species provided useful information about coastal dynamics and sediment transport, and our results confrmed them as reliable proxies of coastal water column turbidity and Volturno river basin runof. Keywords Benthic foraminifera · Beam transmission · Oxygen · Runof · Gulf of Gaeta · Tyrrhenian Sea 1 Introduction Marine coastal environments and related ecosystems (e.g., deltas, wetlands, and estuaries) are naturally and artifcially subject to many and diverse changes (Elliott and Quintino 2007). Due to their location at the land–sea interface, these transitional waters have a strong intrinsic dynamism and marked environmental gradients (e.g., salinity, nutrients, particle size, and dissolved oxygen) (LePage 2011). In shal- low coastal marine areas, benthic foraminiferal assemblages are controlled by a wide range of environmental conditions (Murray 2001) and, whereas the distribution of each spe- cies is unique, groups of species (assemblages or com- munities) can be recognized as inhabiting particular areas and to have specifc characteristics depending by diferent variables (e.g., salinity, particle size, oxygen, organic matter, etc.) (Murray 2001). The existing literature highlighted that among benthic micro-organisms, foraminifera are consid- ered useful for present and past bio-indicators, because (1) their species rapidly react to marine water environmental changes, and (2) they preserve in sediments for a long time due to calcium carbonate shells (hyaline and porcellaneous foraminifera) (Scott et al. 2001). It is well established that benthic foraminiferal responses, such as changes in species richness, dominance of calcareous vs agglutinated species, specifc depth distribution, and test morphology, are related to modifcation in environmental parameters. Among the This contribution is the written, peer-reviewed version of a paper presented at the Conference “Changes and Crises in the Mediterranean Sea” held at Accademia Nazionale dei Lincei in Rome on October 17, 2017. * Luciana Ferraro luciana.ferraro@iamc.cnr.it 1 Istituto per l’Ambiente Marino Costiero, Consiglio Nazionale delle Ricerche, Calata Porta di Massa, Interno Porto di Napoli, 80133 Naples, Italy 2 Istituto di Biomedicina ed Immunologia Molecolare “Alberto Monroy” (IBIM), Consiglio Nazionale delle Ricerche, Via Ugo La Malfa 153, 90146 Palermo, Italy 3 Istituto Nazionale di Geofsica e Vulcanologia, Via della Fagiola 32, 56126 Pisa, Italy