Growth Attenuation with Developmental Schedule Progression in Embryos and Early Larvae of Sterechinus neumayeri Raised under Elevated CO2
Figure 5
Developmental progression and synchrony at specific times over the duration of the experiment.
Samples for each specified day (n>200, each treatment) were scored for developmental stage. A) Relative percentages of normally developed 2–16 cell embryos at 1 day post-fertilization. B) Relative percentages of morulas, and early blastulas (E Blas) at Day 2. Some normally developed embryos were missing a fertilization membrane (no FM-E Blas). C) Day 3 and 5 development. Unhatched (UH) blastulas were observed without cilia (UH-no cilia Blas) on day 3, while ciliated blastulas in various stages were observed at Day 5. Earlier-stage blastulas were unhatched but ciliated (UH+cilia Blas-inset left) or hatched (H Blas). More developed mesenchyme blastulas (Mes Blas) with a distinct vegetal plate were also unhatched and hatched (inset right). D) Gastrulation over days 8–15. Note the change in Y-axis scale. Early gastrula (E Gas) mid-gastrula (M Gas) late gastrula (L Gas) and prism were observed in highly synchronous development. E) Pluteus development at days 20 and 30. Prism and early pluteus (E Plu) were observed at day 20. By day 30 the 4-arms of the plutei are well-developed and some have developed epaulettes (+epau). F) Abnormal development across the experimental period. Percentage of unfertilized and abnormally developed embryos and larvae are shown for the three pCO2 treatments.