A new approach using biomarkers to elucidate the regression state of the invasive alga Caulerpa taxifolia in waters around the Balearic Islands (Western Mediterranean Sea)

Abstract

Invasive algae alter the structure and function of ecosystems. The green alga Caulerpa taxifolia is an invasive alga introduced in the Mediterranean Sea, whereas Caulerpa prolifera is a native species in Mediterranean waters. The aim of the current work was to determine the oxidative status of both Caulerpa species by means of biomarker measures as a possible indicator of the regression state of C. taxifolia in waters around the Balearic Islands (western Mediterranean Sea). The levels of markers of lipid peroxidation, glutathione concentration, activities of antioxidant enzymes and caulerpenyne production were measured in C. prolifera and C. taxifolia fronds. The concentration of the end product of lipid peroxidation, malondialdehyde, was significantly higher in C. taxifolia than in C. prolifera samples. Antioxidant enzyme activities, namely superoxide dismutase glutathione peroxidase and glutathione reductase, as well as the reduced glutathione : glutathione disulfide ratio were lower in C. taxifolia than in C. prolifera, although the concentrations of malondialdehyde were higher in the alien species. No differences were found in catalase activity or in the concentration of caulerpenyne. In conclusion, the invasive alga C. taxifolia presented a more oxidised status, which could be related to its regression in Mallorcan coastal waters.

Entangled fates of holobiont genomes during invasion: nested bacterial and host diversities in Caulerpa taxifolia

“…; Meinesz et al . ; Tejada & Sureda ; Montefalcone et al . ), and the surface covered has regressed by approximately 80%.…”

“…The present comprehensive analysis of diversity patterns based on the recent development of hypervariable markers for the host genome and the unlocking of massive metagenomic characterization of the endophytic bacterial communities made it a triple paradox at the holobiont scale: genotypic (with a single clone), genetic (this clonal lineage logically resulting in limited allelic diversity) and endophytic (extremely reduced diversity of bacterial communities compared to the native area). The paradox, however, may well be lost, or it may not last more than several decades at least in the case of C. taxifolia: since 2004, the species once called 'killer algae' has vanished from several localities (Ivesa et al 2006;Meinesz et al 2010;Tejada & Sureda 2013;Montefalcone et al 2015), and the surface covered has regressed by approximately 80%. This contrasts with the present state in NSW, where the more variable introduced populations currently show no sign of decline, approximately 15 years after their introduction.…”