Temperature tolerance of the deep-sea coral Lophelia pertusa from the southeastern United States

Water temperature may be a primary exogenous determinant of deep-sea coral distributions. The upper thermal threshold for survival of the deep-water coral Lophelia pertusa (Linnaeus, 1758) is generally accepted to be ~12–14 °C, based on field observations of coral distributions. However, hydrographic conditions over coral mounds are dynamic on various scales, often producing temperature fluctuations of unpredictable duration and magnitude. This study investigated the survival of L. pertusa under a range of experimental temperatures: 5, 8 °C (ambient), 15, 20 and 25 °C, for two experimental durations: 24 h and seven days. There was a significant difference (p<0.001) in survival among temperatures after both the 24 h and the seven day experiments. The experimental data were supported by survival data for coral fragments deployed on benthic landers off North Carolina, where historical data show that temperatures over coral mounds vary greatly and reached 15 °C on a recurring basis. Experimental and in situ data suggested that the upper lethal temperature limit for this deep-sea coral species is near 15 °C. Tolerance to fluctuations in environmental variables, such as temperature, decreases the probability of mortality in the face of anomalous events and/or variable environments. Understanding the eco-physiology of structure forming deep-coral taxa will help inform management strategies; for example, preserving those ecosystems that are more resilient to threats from predicted changes.