Effects of ocean acidification on invertebrate settlement at volcanic CO2 vents

Abstract

We present the Wrst study of the eVects of ocean acidiWcation on settlement of benthic invertebrates and microfauna. ArtiWcial collectors were placed for 1 month along pH gradients at CO 2 vents oV Ischia (Tyrrhenian Sea, Italy). Seventy-nine taxa were identiWed from six main taxonomic groups (foraminiferans, nematodes, polychaetes, molluscs, crustaceans and chaetognaths). Calcareous foraminiferans, serpulid polychaetes, gastropods and bivalves showed highly signiWcant reductions in recruitment to the collectors as pCO 2 rose from normal (336-341 ppm, pH 8.09-8.15) to high levels (886-5,148 ppm) causing acidi-Wed conditions near the vents (pH 7.08-7.79). Only the syllid polychaete Syllis prolifera had higher abundances at the most acidiWed station, although a wide range of polychaetes and small crustaceans was able to settle and survive under these conditions. A few taxa (Amphiglena mediterranea, Leptochelia dubia, Caprella acanthifera) were particularly abundant at stations acidiWed by intermediate amounts of CO 2 (pH 7.41-7.99). These results show that increased levels of CO 2 can profoundly aVect the settlement of a wide range of benthic organisms. Communicated by F. Bulleri. M. Cigliano and M. C. Gambi contributed equally.

Adaptation and acclimatization to ocean acidification in marine ectotherms: anin situtransplant experiment with polychaetes at a shallow CO2vent system

“…Used carefully, areas naturally enriched in CO 2 make ideal natural laboratories for investigating such evolutionary questions. Cigliano et al [43] found species-specific patterns of settlement in invertebrates along CO 2 gradients in this vent system, mirrored by patterns of presence/absence and abundance of adults of polychaete species in the hard bottom community [43,45], potentially indicating the presence of adaptation or acclimatization. In particular, around the CO 2 vents of Ischia, some polychaete species maintain high densities along pCO 2 gradients or even increase in density the closer they are to the vents.…”

“…The first three dominate the most intense venting areas [43,45] and are commonly associated with rocky, shallow, vegetated habitat in the Mediterranean and with Posidonia oceanica (L.) Delile, 1813 seagrass beds [47][48][49]. P. dumerilii and S. prolifera are mesoherbivores, whereas A. mediterranea is a filter feeder.…”

“…Thus, it appears that both plasticity and adaptation may be key to prevent species' risk for extinction in the face of ongoing ocean acidification [118], and thus largely determine the fate of marine biodiversity. Nonetheless even within tolerant groups such as the Polychaeta, some species appear sensitive to elevated pCO 2 and at risk of extinction, as they are unable to cope with ocean acidification [43,45,[123][124][125]. Species extinction will cause shifts in community structure and functions, which may ultimately drive important changes in ecosystem functioning [125,126].…”

Calcareous green alga H alimeda tolerates ocean acidification conditions at tropical carbon dioxide seeps

“…Volcanic CO 2 seeps and areas of CO 2 upwelling have been described worldwide in temperate (Calosi et al 2013;Cigliano et al 2010;Hall-Spencer et al 2008;Inoue et al 2013;Johnson et al 2012;Porzio et al 2011) and tropical (Fabricius et al 2011(Fabricius et al , 2014Johnson et al 2012;Noonan et al 2013;Russell et al 2013;Uthicke and Fabricius 2012;Uthicke et al 2013) regions. So far, studies suggest reduced pH at CO 2 seeps in PNG lead to a decline in coral diversity with structurally complex species being particularly affected, and reduced taxonomic richness and density of coral juveniles, and low cover of crustose coralline algae (Fabricius et al 2011(Fabricius et al , 2014.…”

Effects of low-pH stress on shell traits of the dove snail, <i>Anachis misera</i>, inhabiting shallow-vent environments off Kueishan Islet, Taiwan

“…Studies conducted in the natural vent system at Ischia, Italy, indicated that the settlement and colonization of mollusks and microfauna showed high reductions in recruitment in the acidified stations (Cigliano et al, 2010;Ricevuto et al, 2012;Milazzo et al, 2014). In experiments in which juvenile pen shells Pinna nobilis were transplanted to Ischia for 45 days, decreases in survival, growth, and oxygen consumption were found.…”