Long-term physiological responses to combined ocean acidification and warming show energetic trade-offs in an asterinid starfish

• Published in: Coral Reefs
• Main Authors: Khalil, Munawar, Doo, Steve S., Stuhr, Marleen, Westphal, Hildegard
• Other Authors: Physical Science and Engineering (PSE) Division, Biological and Environmental Science and Engineering (BESE) Division, Red Sea Research Center (RSRC), Leibniz Centre for Tropical Marine Research (ZMT), Fahrenheitstraße 6, 28359, Bremen, Germany, Faculty of Geosciences, University of Bremen, Klagenfurter Str. 2-4, 28359, Bremen, Germany, Department of Marine Science, Faculty of Agriculture, Universitas Malikussaleh, Reuleut Main Campus, North Aceh, 2435, Indonesia
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Springer Science and Business Media LLC 2023
• Subjects: Ocean acidification
• Online Access: http://hdl.handle.net/10754/692100; https://doi.org/10.1007/s00338-023-02388-2

While organismal responses to climate change and ocean acidification are increasingly documented, longer-term (> a few weeks) experiments with marine organisms are still sparse. However, such experiments are crucial for assessing potential acclimatization mechanisms, as well as predicting species-specific responses to environmental change. Here, we assess the combined effects of elevated pCO2 and temperature on organismal metabolism, mortality, righting activity, and calcification of the coral reef-associated starfish Aquilonastra yairi. Specimens were incubated at two temperature levels (27 °C and 32 °C) crossed with three pCO2 regimes (455 µatm, 1052 µatm, and 2066 µatm) for 90 days. At the end of the experiment, mortality was not altered by temperature and pCO2 treatments. Elevated temperature alone increased metabolic rate, accelerated righting activity, and caused a decline in calcification rate, while high pCO2 increased metabolic rate and reduced calcification rate, but did not affect the righting activity. We document that temperature is the main stressor regulating starfish physiology. However, the combination of high temperature and high pCO2 showed nonlinear and potentially synergistic effects on organismal physiology (e.g., metabolic rate), where the elevated temperature allowed the starfish to better cope with the adverse effect of high pCO2 concentration (low pH) on calcification and reduced skeletal dissolution (antagonistic interactive effects) interpreted as a result of energetic trade-offs. This research project was supported by the Leibniz Centre for Tropical Marine Research (ZMT) Academy–Doctoral Research Grant, and by the MoECRT, Republic of Indonesia–ADB AKSI Project [grant number L3749-INO] to MK. SSD was funded by the Alexander von Humboldt Stiftung Foundation Postdoctoral Fellowship. We are grateful to the Ministry of Education, Culture, Research, and Technology (MoECRT), Republic of Indonesia—Asian Development Bank (ADB) AKSI Project for a doctoral scholarship granted to MK. ...