Vulnerability of the calcifying larval stage of the Antarctic sea urchin Sterechinus neumayeri to near-future ocean acidification and warming

• Published in: Global Change Biology
• Main Authors: Byrne, M, Ho, MA, Koleits, LJ, Price, C, King, CK, Virtue, P, Tilbrook, B, Lamare, M
• Format: Article in Journal/Newspaper
• Language: English
• Published: Blackwell Publishing Ltd 2013
• Subjects: Biological Sciences; Ecology; Marine and estuarine ecology (incl. marine ichthyology); Antarctic; The Antarctic; Antarc*; Ocean acidification
• Online Access: http://dx.doi.og/10.1111/gcb.12190; https://doi.org/10.1111/gcb.12190; http://www.ncbi.nlm.nih.gov/pubmed/23504957; http://ecite.utas.edu.au/85609

Stenothermal polar benthic marine invertebrates are highly sensitive to environmental perturbations but little isknown about potential synergistic effects of concurrent ocean warming and acidification on development of theirembryos and larvae. We examined the effects of these stressors on development to the calcifying larval stage in theAntarctic sea urchin Sterechinus neumayeri in embryos reared in present and future (2100+) ocean conditions fromfertilization. Embryos were reared in 2 temperature (ambient: -1.0 Celsius degree, + 2 Celsius degree : 1.0 Celsius degree) and 3 pH (ambient: pH 8.0,-0.2-0.4 pH units: 7.8,7.6) levels. Principle coordinates analysis on five larval metrics showed a significant effect oftemperature and pH on the pattern of growth. Within each temperature, larvae were separated by pH treatment, apattern primarily influenced by larval arm and body length. Growth was accelerated by temperature with a 20-28%increase in postoral (PO) length at +2 Celsius degree across all pH levels. Growth was strongly depressed by reduced pH with a8-19% decrease in PO length at pH 7.6-7.8 at both temperatures. The boost in growth caused by warming resulted inlarvae that were larger than would be observed if acidification was examined in the absence of warming. However,there was no significant interaction between these stressors. The increase in left-right asymmetry and altered bodyallometry indicated that decreased pH disrupted developmental patterning and acted as a teratogen (agent causingdevelopmental malformation). Decreased developmental success with just a 2 Celsius degree warming indicates that developmentin S. neumayeri is particularly sensitive to increased temperature. Increased temperature also altered larvalallometry. Altered body shape impairs swimming and feeding in echinoplutei. In the absence of adaptation, itappears that the larval phase may be a bottleneck for survivorship of S. neumayeri in a changing ocean in a locationwhere poleward migration to escape inhospitable conditions is not ...