HYPOXIA DISRUPTS METABOLISM IN CORAL AND SEA ANEMONE LARVAE

Anthropogenic environmental inputs are driving seawater hypoxia in tropical coral reefs and temperate estuaries. Little is known regarding how the larvae of reef-building corals and estuarine sea anemones are impacted by hypoxia, yet this knowledge is critical for predicting species’ trajectories. To explore this key question, we exposed stage-matched larvae (planulae) of the reef-building corals Galaxea fascicularis and Porites astreoides and the sea anemone Nematostella vectensis to a simulated hypoxic event (6 h at 2 mg dissolved oxygen L^-1). Interestingly, larvae of all three species decreased swimming following hypoxia, while only the coral larvae showed declines in aerobic respiration rates. These responses were correlated with changes in metabolite abundances quantified via liquid chromatography-mass spectrometry. Specifically, larvae exposed to hypoxia showed decreases in aerobic pathways including fatty acid oxidation and oxidative phosphorylation, instead relying on glycolysis, ketone body usage, the citric acid cycle, and branched-chain amino acid metabolism to produce cellular energy. While these metabolic adjustments likely promoted short-term survival, all three species still displayed decreases in long-term performance (e.g., growth). Thus, metabolic acclimation was insufficient to protect larvae from the negative effects of hypoxia. Overall, these findings demonstrate that hypoxia presents a significant threat to coral and sea anemone early life stages, emphasizing the need to limit the drivers of ocean deoxygenation for their persistence.

Presentation Preference: Oral

Primary Presenter: Benjamin Glass, University of Pennsylvania (benglass@sas.upenn.edu)

Authors:

Benjamin Glass, University of Pennsylvania  (benglass@sas.upenn.edu)

Katie Barott, University of Pennsylvania  (kbarott@sas.upenn.edu)