Organisms are highly sensitive to global warming, which especially threatens marine organisms. Marine vegetated habitats provide dial fluctuations of oxygen, creating hyperoxic environments during the day that could potentially increase the resistance of organisms to thermal stress. Although these habitats provide food and shelter for many marine organisms, we lack an understanding of the potential benefits of naturally occurring dial oxygen fluctuations on temperature-sensitive marine biota. We experimentally tested if dial fluctuation of oxygen affects the metabolic performance and behaviour of the sea urchin Paracentrotus lividus. Sea urchins were exposed to dial-oxygen fluctuations produced by macroalgae for 11 days at 5 targeted temperatures (20, 23, 26, 29, and 32 ^oC). We found that respiration rates at the optimal temperature (29 ^oC) doubled at the peak of oxygen concentration during the day (2.72 mg O₂ h^-1 urchin^-1) than at the valley of oxygen concentration at night (1.41 mg O₂ h^-1 urchin^-1). Oxygen concentration also affected the behavioral response of the sea urchin, where we found shorter righting response (time to turn from the aboral side to the oral side) on urchins during the peak of oxygen (average 218 s) than at the oxygen valley (average 280 s). This study reveals that marine vegetated habitats induce changes in oxygen concentration that might critically affect the metabolic performance and behaviour of marine organisms along a thermal gradient.

Primary Presenter: Andrea Anton, IMEDEA (UIB-CSIC) (andrea.anton@imedea.uib-csic.es)

Authors:

Andrea Anton, IMEDEA (UIB-CSIC)  (andrea.anton@imedea.uib-csic.es)

Nuria Marba, IMEDEA  (nmarba@imedea.uib-csic.es)