How could inorganic eutrophication affect the susceptibility of pulsating soft corals to warming?

Ana Yanez Suarez

Ocean warming and inorganic eutrophication negatively affect corals and their reefs. These factors could cause phase shifts from hard corals to soft corals, but knowledge about the physiological responses of soft corals under these environmental changes is needed.

This theoretical thesis reviewed 53 scientific papers that investigated the effects of a) inorganic eutrophication (42%), b) temperature (47%) and c) a combination of both factors (13%) on soft and hard corals. Additionally, 38 papers were studied to describe the ecophysiology of soft corals. Findings revealed that eutrophication was linked to shifts from hard corals towards algae and towards soft corals in 40% and 11% of literature respectively. Warming reduced growth and survival of corals in 70% of studies. Changes in nitrogen:phosphate ratios due to eutrophication were correlated to an increase in sensitivity of hard corals to warming. Related studies for soft corals are needed.

Specific traits may give soft corals survival advantages over hard corals. This thesis focuses on pulsating soft corals (PSC) since their unique pulsation enhances food supply. An experimental design is proposed to explore the physiological and biogeochemical responses of PSC exposed to inorganic eutrophication and warming. I hypothesize that the pulsation of PSC may help them to withstand inorganic eutrophication and warming.