Contrast in larval sensitivity to low pH in sea urchins from neighbouring seagrass meadows at Inhaca Island, Mozambique

Sea urchin larvae from intertidal seagrass meadows at Inhaca Island, Mozambique, exhibit greater sensitivity to low pH conditions compared to their subtidal counterparts. This contrast suggests that local adaptation to pH variability may differ between intertidal and subtidal environments, challenging the assumption that physiological tipping points universally correlate with the lowest experienced pH in an organism's range. Researchers exposed larvae of Tripneustes gratilla from two neighboring seagrass habitats—one subtidal (EBMI) and one intertidal (Banguá)—to four pH treatments (ranging from 8.04 to 7.29) for seven days, observing declines in survival, growth, and symmetry under lower pH conditions. The findings imply that subtidal urchins, which experience more stable pH, may possess distinct mechanisms for pH tolerance, highlighting potential vulnerabilities as ocean acidification intensifies.

Duvane, J., Cossa, D., de Abreu, D., Mafambissa, M., Scarlet, M., Macia, A., & Dupont, S. (2024). Contrast in larval sensitivity to low pH in sea urchins from neighbouring seagrass meadows at Inhaca Island, Mozambique. African Journal of Marine Science, 46(3), 217–226. https://doi.org/10.2989/1814232x.2024.2387062