The purpose of this experimental study is to assess the impact of different concentrations ofchromium (Cr) through time on the diversity of cultured benthic foraminifera combining twomorphological approaches for the identification of living specimens that are Rose Bengal (RB)staining and CellTracker Green (CTG) labelling as well as environmental DNA and RNAmetabarcoding. Seven tanks/aquaria with different concentrations of Cr in water, namely 100 ppt, 1ppb, 10 ppb, 100 ppb, 1 ppm and 10 ppm plus the control were used. A mesocosm was extractedfrom each tank at pre-established time (1 week, 2 weeks, 4 weeks 6 weeks and 8 weeks).Morphological analyses produced 6 datasets based on staining techniques (RB vs. CTG) and theconsidered sediments’ fractions (>125 μm, 63-125 μm and >63 μm) and several foraminiferalparameters (i.e., S, H’ and Fisher α index). On the basis of the correlation analyses, no significantcorrelations among diversity indexes calculated for RB and Cr concentrations in water and sedimentwere found. On the contrary, significant negative correlation values were observed betweendiversity indexes from the CTG datasets and Cr concentrations in sediment. Molecular analysesproduced 6 datasets (Filter 1, 10 and 100 for both eDNA and eRNA). In all datasets generated fromthe eRNA but not with eDNA analyses, the diversity decreased with increasing Cr concentrations.Environmental DNA/RNA metabarcoding show evidence that Cr pollution has detrimental effects onbenthic foraminifera. Compared to morphological approach, the metabarcoding offers severaladvantages, such as wider range of analyzed foraminiferal taxa among which some may be potentialkey indicators of Cr pollution. This study further supports foraminiferal metabarcoding as acomplementary and/or alternative method to standard biomonitoring program based on themorphological identification of species communities.
|Number of pages||0|
|Publication status||Published - 2018|