Live benthic foraminiferal faunas from the French Mediterranean Coast: Towards a new biotic index of environmental quality

Abstract

In this study, living (Rose Bengal stained) foraminiferal faunas from 31 stations along the entire French Mediterranean Sea coast except Corsica have been analysed. In the context of the Water Framework Directive, the aim was to develop a biotic index to evaluate the benthic ecosystem quality. Therefore, different faunal parameters (diversity indices, wall structure proportion, and indicative species groups) have been tested to determine their relevance as indicators of environmental conditions. The best results are obtained with a biotic index based on the relative proportion of stress-tolerant taxa. For ecosystem quality evaluation, it is essential to distinguish between natural and anthropogenic eutrophication phenomena. In order to do so, we applied a correction on our biotic index, using the expected percentage of stress-tolerant species in natural environments, in function of sediment grain size (percentage <63 μm). Finally, a comparison of the different faunal parameters calculated for two different sediment intervals (0-1 and 0-4 cm) indicates clearly that the analysis of the uppermost centimetre of the sediment is sufficient to obtain relevant information needed for bio-monitoring purposes. Highlights ► Development of a biotic index based on benthic foraminiferal faunas. ► Discriminate between natural and anthropogenic eutrophication. ► Relevance of foraminiferal parameters for the development of biotic index. ► Inventory of living benthic foraminiferal faunas of the French Mediterranean coast. ► Restrict faunal analysis to the first cm of sediment for bio-monitoring studies.

Developing Foram-AMBI for biomonitoring in the Mediterranean: Species assignments to ecological categories

“…The final list of species assignments is the fruit of a very thorough and objective inspection of all existing Mediterranean BF data sets until 2014. We think that this list is an essential tool for all bio-indication methods, which use the relative proportions of stress-tolerant and/or stress-sensitive taxa to obtain a quantified measure of the EQS, either by Foram-AMBI (Alve et al, 2016) or by a comparable method (e.g., Barras et al, 2014;Dimiza et al, 2016).…”

“…Finally, after constructing this list, the next step is to test it on independent data sets, containing also TOC measurements, either by using Foram-AMBI (Alve et al, 2016) or similar methods (e.g., Barras et al, 2014;Dimiza et al, 2016). Another objective for further studies is the comparison of ecological assignments of Mediterranean and Atlantic species (Alve et al, 2016).…”

“…The consequence is that in natural conditions, clayey sediments usually have a higher TOC content than sandy sediments. In natural conditions, BF faunas found on sandy sediments with low TOC contents usually have a high contribution of epiphytic/epifaunal taxa, which are generally considered as pollution-sensitive (e.g., Barras et al, 2014). Conversely, the faunas of clayey substrates often contain high proportions of stress-resistant taxa (e.g., Jorissen, 1987;Celia Magno et al, 2012).…”

A multidisciplinary approach to study confined marine basins: the holobenthic and merobenthic assemblages in the Mar Piccolo of Taranto (Ionian Sea, Mediterranean)

“…Due to some peculiar features, like the short life cycles and the high turnover rate, together with the good preservation of the tests, the high abundance in marine sediments, the worldwide distribution and the high number of specimens that can be retrieved from a relatively small sample (a few cm 3 of sediment), foraminifera have a potential higher than macrofauna to reveal changes in environmental conditions (Alve 1995;Debenay et al 1996;Scott et al 2005;Murray 2006;Alve et al 2009;Cherchi et al 2009;Jorissen et al 2009;Frontalini and Coccioni 2011;Bouchet et al 2012;Schönfeld et al 2012;Barras et al 2014;Martins et al 2015a, c). Generally, their response to natural stress and/or anthropogenic impact can be observed at both the community (total abundance, species richness and ecological diversity) and the species levels (e.g.…”

Recent benthic foraminiferal assemblages and their relationship to environmental variables on the shoreface and inner shelf off Valencia (Western Mediterranean)

“…In the western Mediterranean, several studies of recent benthic foraminifera have been carried out, in Italy (Donnici and SerandreiBarbero, 2002;Frontalini and Coccioni, 2011;Magno et al, 2012), on the French Mediterranean coast (Mojtahid et al, 2008;Goineau et al, 2011;Fontanier et al, 2012;Barras et al, 2014) and off the Spanish coast (deep-sea) (Mateu, 1970;Milker et al, 2009;MateuVicens et al, 2010;Contreras-Rosales et al, 2012). At present there are few studies of the superficial distribution of benthic foraminifera on the inner shelf of the eastern seaboard of Spain (Bl azquez, 1996;Usera and Bl azquez, 1997) and hardly any of the inner shelf or shoreface off the coast of Castell on province and the north of Valencia (Bl azquez and Alc antara-Carri o, 2009).…”