Effects of marine heatwave conditions across the metamorphic transition to the juvenile sea urchin (Heliocidaris erythrogramma)

Live‐fast‐die‐young: Carryover effects of heatwave‐exposed adult urchins on the development of the next generation

“…Larvae to juvenile development of the starfish Parvulastra exigua was faster when exposed to MHW temperatures; however, survival rates decreased from 1 to 5 days post‐fertilization (Balogh & Byrne, 2020). Similar to the finding of our study, Heliocidaris erythrogramma juvenile tolerance has been shown to be plastic throughout development, with higher upper successful metamorphosis temperatures of 25.9°C by day 7 of development (+5°C above higher ambient conditions in the region), but by day 10 the juvenile tolerance narrowed back down to local range (16–19°C; Gall et al, 2021). Therefore, while this heat priming of the parents indicated that there are maternal factors passed onto the next generation which facilitate growth and survival in early benthic development, ultimately, this may not be efficient to ensure continued survival into the more sensitive later juvenile stages when most maternal reserves are gone (Byrne & Sewell, 2019; Emlet & Hoegh‐Guldberg, 1997; Falkner et al, 2015).…”

“…There were also carryover effects from larvae to juvenile; Larvae to juvenile development of the starfish Parvulastra exigua was faster when exposed to MHW temperatures; however, survival rates decreased from 1 to 5 days post-fertilization (Balogh & Byrne, 2020). Similar to the finding of our study, Heliocidaris erythrogramma juvenile tolerance has been shown to be plastic throughout development, with higher upper successful metamorphosis temperatures of 25.9°C by day 7 of development (+5°C above higher ambient conditions in the region), but by day 10 the juvenile tolerance narrowed back down to local range (16-19°C;Gall et al, 2021).…”

“…Temperature treatments were created using two aluminium temperature blocks set up in parallel that allowed for 12 temperature treatments with 1°C increments across a static thermal gradient, established using hot (28°C) and cold (22°C) water inputs at either end (Figure S1 ). The 22–28°C range included the temperature experienced by the parents and the upper lethal temperatures for this species (Gall et al, 2021 ). Each block had four columns of holes to fit the glass vials used across the 12 temperatures.…”

Staying in place and moving in space: Contrasting larval thermal sensitivity explains distributional changes of sympatric sea urchin species to habitat warming

“…For C. rodgersii, the broad thermal range and thereby stress tolerance of the larvae of abundant populations provided the source for invasion of Tasmania. For both species, the decrease in thermal tolerance over developmental time shows that present-day heatwaves are likely to be deleterious for the larvae as shown for H. erythrogramma (Gall et al, 2021).…”

Post-bleaching alterations in coral reef communities

“…For example, sea urchin densities across the Chumbe Reef Sanctuary have been gradually declining, while fish densities have been gradually increasing between the years 2006 and 2015 (Kloiber, 2015). Another plausible explanation for observed low post-bleaching densities may be recruitment failure, arising from elevated SST on fertilization success, and also the development of larvae and juvenile sea urchins (Pereira et al, 2020;Gall et al, 2021;Leach et al, 2021).…”