The sibling polychaetes Platynereis dumerilii and Platynereis massiliensis in the Mediterranean Sea: are phylogeographic patterns related to exposure to ocean acidification?

Clarifying the taxonomic status of the alien species Branchiomma bairdi and Branchiomma boholense (Annelida: Sabellidae) using molecular and morphological evidence

“…This study revealed significant genetic differentiation in the mitochondrial gene COI between Mediterranean and extra-Mediterranean Branchiomma populations, strongly suggesting that they represent two different species. Observed values of pairwise Φ ST and average K2P genetic distance denoted that the two groups of populations belong to two different congeneric species, indeed the levels of genetic distance (K2P) observed between the two groups of populations were similar to those reported for other congeneric polychaete species [ 18 , 79 – 85 ]. The results obtained from the phylogenetic analysis emphasized the strong separation between the two forms as well: sequences obtained from extra-Mediterranean samples and Mediterranean ones clustered in two distinct and well supported clades.…”

“…In particular, among the examined sites around Ischia Island the species was collected also at the Castello Aragonese vent’s system, a venting area where intense CO 2 emissions lower the seawater pH up to 6.6 values [ 95 ] and where the few polychaete species collected in this site respond to stress either by acclimating via phenotypic plasticity (e.g the sabellid Amphiglena mediterranea ) or through genetic adaptation (e.g. the nereidid Platynereis spp ) [ 85 , 96 , 97 ]. Branchiomma boholense seems to acclimate to the CO 2 vent conditions like A .…”

Antioxidant Efficiency ofPlatynereisspp. (Annelida, Nereididae) under Different pH Conditions at aCO2Vent’s System

“…Conversely, the overall ability of the vent population to maintain stable levels of antioxidant defences, regardless the period of the year and seasonal-related trends, suggested that natural enhancement of environmental prooxidant conditions was balanced with slight changes of individual antioxidants. The different native pH conditions, over three sampling periods, were not translated into significant differences between populations in the other antioxidant biomarkers analysed, and the similar antioxidant responses Journal of Marine Biology 7 highlighted between the two populations confirmed the high tolerance of these species (or complex of sibling species, [47]). The long-term exposure to moderately elevated pCO 2 conditions, such as those expected in global climate change scenarios at the end of this century [1], could minimally affect the cellular redox status, as already observed in two marine bivalve species, Crassostrea virginica and Mercenaria mercenaria [9].…”

“…The genotype of the acidified areas was later identified as the only known sibling species of Platynereis dumerilii, P. massiliensis (Moquin-Tandon, 1869): morphologically indistinguishable species in its adult (nonreproductive) stage, but characterized by a completely different reproductive biology [44][45][46]. A recently published study that combined together genetic and reproductive biology analyses revealed that both Platynereis species actually represented two different complexes of siblings [47]. Based on preliminary genetic results, the Castello vent site of Ischia appeared dominated by the brooding P. massiliensis sibling, while the control site by the broadcasting species P. dumerilii [24,46,47].…”

“…A recently published study that combined together genetic and reproductive biology analyses revealed that both Platynereis species actually represented two different complexes of siblings [47]. Based on preliminary genetic results, the Castello vent site of Ischia appeared dominated by the brooding P. massiliensis sibling, while the control site by the broadcasting species P. dumerilii [24,46,47]. In the long-term translocation (30 days) the antioxidant sensitivity of different polychaete species (Platynereis dumerilii, Polyophthalmus pictus, and Syllis prolifera) and their antioxidant capacity to counteract oxyradicals formation in control and low pH conditions was evaluated, highlighting as the population of Platynereis originating from the vent showed higher constitutive antioxidant efficiency [12], which may allow them to cope with short-term and chronic exposure to higher oxidative pressure without further enhancement of antioxidant defences [12].…”