Decreased pH does not alter metamorphosis but compromises juvenile calcification of the tube worm Hydroides elegans

Abstract

Using CO2 perturbation experiments, we examined the pre- and post-settlement growth responses of a dominant biofouling tubeworm (Hydroides elegans) to a range of pH. In three different experiments, embryos were reared to, or past, metamorphosis in seawater equilibrated to CO2 values of about 480 (control), 980, 1,480, and 2,300 μatm resulting in pH values of around 8.1 (control), 7.9, 7.7, and 7.5, respectively. These three decreased pH conditions did not affect either embryo or larval development, but both larval calcification at the time of metamorphosis and early juvenile growth were adversely affected. During the 24-h settlement assay experiment, half of the metamorphosed larvae were unable to calcify tubes at pH 7.9 while almost no tubes were calcified at pH 7.7. Decreased ability to calcify at decreased pH may indicate that these calcifying tubeworms may be one of the highly threatened species in the future ocean.

A snapshot of ocean acidification research

“…It was also confirmed that transition phases such as fertilization can be negatively impacted (Gonzalez-Bernat et al 2012;Lewis et al 2012). In contrast, larval metamorphosis into juveniles remained unaffected in echinoderms and annelids Lane et al 2012). Five studies showed that ocean acidification alone or in combination with temperature change can impact behavior in fish (Devine and Munday 2012;Munday et al 2012, but see Maneja et al 2012), mollusks (Schalkhausser et al 2012) and crustaceans (Zittier et al 2012).…”

“…These studies reported a range of responses. For example, it was shown that calcification can be strongly inhibited under ocean acidification (e.g., Lane et al 2012; Fig. 6a), but can also be stimulated leading to hyper-calcification (e.g., Dorey et al 2012).…”

“…4 Summary of impacts on fitness of species studied in this volume (relative number of species) Fig. 5 Relative numbers of species studied showing negative (e.g., increased mortality), neutral or positive (e.g., increased reproduction and survival) impacts on fitness of both non-calcifiers and calcifiers ecological interactions demonstrated the importance to include the whole life cycle in future experimental design (larvae and juveniles: Dorey et al 2012;Lane et al 2012;adult-larvae: Uthicke et al 2012;adult-larvae-juvenile: Dupont et al 2012; the whole life cycle: Troedsson et al 2012). For example, urchin larvae exposed to ocean acidification produced juveniles that were 10 times more sensitive to ocean acidification .…”

Effect of temperature rise and ocean acidification on growth of calcifying tubeworm shells (<i>Spirorbis spirorbis</i>): an in situ benthocosm approach

“…Most studies have focused on the tropical species Hydroides elegans (Lane et al, 2013;Chan et al, 2012Chan et al, , 2013Mukherjee et al, 2013;Li et al, 2014). The results indicated reduced growth, increased porosity and reduced mechanical strength of the worm tubes, as well as increased mortality of larvae at lowered pH (< 7.9).…”

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

“…molluscs and crustaceans) (cf. [39][40][41]). Here using field transplant experiments, we looked for evidence of physiological acclimatization or adaptation in these species.…”