A new study reveals that altering the feeding habits of coral reefs can aid their recovery from devastating bleaching events caused by rising ocean temperatures and climate change.
Bouncing Back from Bleaching
For the past decade, catastrophic bleaching events in coral reefs around the world have drawn headlines about the global threats of climate change: rising oceans and acidification. While bleak, the dire effects of these events are meant to wipe out coral populations, increasing reduction rates and over time tearing apart entire ecosystems into nothing but pieces.
Recently a new study, led by Kerri Dobson, a graduate student at Ohio State University, has however noticed an unusual way how coral reefs could end their recovery from all these bleaching activities. By changing what coral eat, the researchers discovered that these organisms can withstand and recover from extreme temperatures even under high heat stress.
The Power of Feeding
Corals usually get their food from two primary sources: symbiotic algae living within their tissue, which are photosynthetic and live off of the sunlight, or by capturing tiny marine organisms called zooplankton. Coral also gets its colors from these same algae, but under heat stress coral can expel the algae and bleach white while starving.
Scientists collected branch samples from bleached and non-bleached coral colonies after the two heat-stress events in 2014 and 2015 for their research. They put the corals in experimental tanks and fed them different amounts of food and exposed them to various rates of simulated ocean acidification to determine how these influences affected their resilience.
The results were impressive: the researchers demonstrated that the mere act of feeding zooplankton to weak, starving coral after a bleaching event could help to suppress mortality and promote growth in high temperatures, which would otherwise have delayed their recovery. The simulated ocean acidification did not seem to effect the ability of corals to recover, at least in a few species, suggesting that certain types of corals may be able to survive in more acidic waters.
Conclusion
This study is a landmark one, and hopefully will offer light through the darkness that surrounds coral reefs due to climate change. This newfound recognition of the fundamental importance that feeding plays on coral resilience and recovery may enable scientists, as well conservation efforts to develop tailored management and restoration strategies aimed at better supporting these critical ecosystems. While global warming and ocean acidification continue to threaten, this research suggests that easy interventions like feeding corals may be critical for their survival when the next wave of bleaching comes.
