Benthic foraminifera as bio-indicators of trace element pollution in the heavily contaminated Santa Gilla lagoon (Cagliari, Italy) Fabrizio Frontalini a, * , Carla Buosi b , Stefania Da Pelo b , Rodolfo Coccioni a , Antonietta Cherchi b , Carla Bucci a a Università degli Studi di Urbino ‘‘Carlo Bo”, Dipartimento di Scienze dell’Uomo, dell’Ambiente e della Natura, Campus Scientifico, Località Crocicchia, 61029 Urbino, Italy b Università di Cagliari, Dipartimento di Scienze della Terra, via Trentino 51, 09127 Cagliari, Italy article info Keywords: Benthic foraminifera Trace elements Foraminiferal test ESEM-EDS Santa Gilla lagoon (Sardinia) Nanoparticles abstract In order to assess the response of benthic foraminifera to trace element pollution, a study of benthic fora- miniferal assemblages was carried out into sediment samples collected from the Santa Gilla lagoon (Sardinia, Italy). The lagoon has been contaminated by industrial waste, mainly trace elements, as well as by agricultural and domestic effluent. The analysis of surficial sediment shows enrichment in trace ele- ments, including Cr, Cu, Hg, Ni, Pb and Zn. Biotic and abiotic data, analyzed with multivariate techniques of statistical analysis, reveal a distinct separation of both the highly polluted and less polluted sampling sites. The innermost part of the lagoon, comprising the industrial complex at Macchiareddu, is exposed to a high load of trace elements which are probably enhanced by their accumulation in the finer sediment fraction. This area reveals lower diversity and higher percentages of abnormalities when compared to the outermost part of the lagoon. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction Benthic foraminifera (class Foraminifera, phylum Granuloretic- ulata) constitute the most diverse group of shelled micro organ- isms in modern oceans (Sen Gupta, 1999). They play a significant role in global bio-geochemical cycles of inorganic and organic com- pounds, making them one of the most important animal groups on earth (Haynes, 1981; Lee and Anderson, 1991). Since foraminifera have a short life-cycle, they react quickly and can be used as early warning bio-indicators of both short and long-term changes in marine and transitional-marine environments on a global and a lo- cal scale (e.g. Alve, 1991, 1995; Yanko et al., 1994, 1998, 1999; Coc- cioni, 2000; Samir, 2000; Debenay et al., 2001, 2005; Samir and El- Din, 2001; Murray and Alve, 2002; Geslin et al., 2002; Coccioni et al., 2003, 2005; Armynot du Châtelet et al., 2004; Frontalini and Coccioni, 2008). The use of benthic foraminifera as bio-indica- tors of environmental quality may be investigated in terms of pop- ulation density and diversity, assemblages’ structure, reproduction capability, test morphology, including size (dwarfism), prolocular morphology, ultrastructure, pyritization, abnormality, and chemis- try of the test (e.g. Alve, 1991, 1995; Yanko et al., 1994, 1999; Ges- lin et al., 1998). The study of pollution effects on benthic foraminifera and their use as proxies started in the 1960s (Resig, 1960; Watkins, 1961; Boltovskoy, 1965), and has increasingly developed in recent dec- ades through environmental research (e.g. Boltovskoy et al., 1991; Alve, 1991, 1995; Yanko et al., 1994, 1998, 1999; Stouff et al., 1999; Coccioni, 2000; Geslin et al., 2000, 2002; Debenay et al., 2001, 2005; Coccioni et al., 2003, 2005; Coccioni and Marsili, 2005; Ferraro et al., 2006; Frontalini and Coccioni, 2008; Polovodo- va and Schönfeld, 2008; Romano et al., 2008). Morphological abnormalities in foraminiferal tests have been noted by researchers as long ago as the past two centuries (e.g. Carpenter, 1856; Rhumbler, 1911). In some modern assemblages, deformed tests are conspicuously abundant and the causes there- of are of great interest. In particular, abnormalities have been re- ported in areas contaminated by trace elements, domestic sewage, and various chemicals, including liquid hydrocarbons (for reviews see Boltovskoy et al., 1991; Alve, 1995; Yanko et al., 1998). The percentage of abnormal foraminifera can in- crease dramatically in polluted areas (e.g. Lidz, 1965), and most of the authors mentioned above have suggested that the presence of deformed tests of benthic foraminifera is a powerful in situ bio- indicator of trace element pollution. In particular, Coccioni et al. (2005) introduced the Foraminiferal Abnormality Index (FAI) to index and compare the percentages of morphological abnormality occurring at different sites. More recently, the possibility of using the trace element content of calcareous benthic foraminiferal tests as a reliable tracer of environmental quality has also been explored. Following on from this, and within integrated programs, benthic foraminifera could be used as valuable bio-indicators of contemporary environmental changes and disturbances caused by pollution. 0025-326X/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.marpolbul.2009.01.015 * Corresponding author. Tel.: +39 0722 304254; fax: +39 0722 304220. E-mail address: fabrizio.frontalini@uniurb.it (F. Frontalini). Marine Pollution Bulletin 58 (2009) 858–877 Contents lists available at ScienceDirect Marine Pollution Bulletin journal homepage: www.elsevier.com/locate/marpolbul