Coral Resilience to Future Ocean Conditions
Coral reefs are an important biodiverse marine ecosystem that provide goods and services to maritime tropical nations. However, due to increasing greenhouse gases in the atmosphere, the temperature of seawater is elevating and pH is dropping (ocean warming and ocean acidification). At elevated temperatures, coral lose their algal symbionts (Symbiodiniaceae), which renders the coral pale or white (coral “bleaching”) and often results in their death. In healthy coral, Symbiodiniaceae can provide the coral animal with up to 100% of its daily metabolic energy requirement, however, it can also receive energy through feeding (heterotrophy). It has been found that some species can increase their heterotrophy or increase the proportionate contribution of heterotrophic vs photoautotrophic carbon in their tissues when bleached to meet energy demands, and are then able to recover more quickly from bleaching. Studies suggest that coral species capable of doing so will be more resilient to bleaching events over the long-term.
In collaboration with Dr. Rob Toonen’s lab at the Hawaii Institute of Marine Biology (HIMB) in Oahu, Hawaii (http://tobolab.org/), we are studying a potential technological intervention strategy (Underwater Zooplankton Enhancement Light Array UZELA) to increase feeding on reefs and minimize coral bleaching impacts. We will be looking at Montipora capitata and Porites compressa, two Hawaiian corals that have been found to increase their feeding effort in response to increases in zooplankton availability. Different physiological parameters will be analyzed to determine the effectiveness of our proposed prototype.
Photo of a UZELA rack being used in ongoing experiment at HIMB