Coral Reef Adaptation to Warming Seas
Resilient Coral Species Offer Hope, But Face Limits in Warming oceans
COLUMBUS, Ohio – As coral reefs worldwide face unprecedented decline due to rising ocean temperatures, a new study offers a glimmer of hope, revealing that some coral species possess a surprising degree of resilience. However, the research also underscores the limits of this resilience in the face of continued warming.
Scientists at the Ohio State University, in collaboration with international researchers, investigated the effects of prolonged exposure to elevated temperatures on Stylophora pistillata, a coral species found in the northern Red Sea known for its tolerance to high ocean temperatures. Their findings, published in the journal Science of the Total Habitat, reveal a complex picture of survival and compromise.
The team subjected S. pistillata to temperatures of 27.5 and 30 degrees Celsius (81.5 and 86 degrees Fahrenheit) for six months, mimicking the baseline warming expected in tropical oceans by 2050 and 2100, respectively. While the coral survived, important changes were observed. Corals in the 27.5-degree Celsius waters were 30% smaller than the control group, while those in the 30-degree Celsius waters were a staggering 70% smaller.
“In theory, if corals in the wild at these temperatures are smaller, reefs might not be as diverse and may not be able to support as much marine life,” explains Ann Marie Hulver, lead author of the study and a former graduate student and postdoctoral scholar in earth sciences at The Ohio State University. “This could have adverse effects on people that depend on the reef for tourism, fishing, or food.”
The study revealed that the cumulative impact of chronic high temperatures, rather than initial exposure, was the primary driver of compromised coral growth and increased metabolic demand. Interestingly, when the coral was later exposed to cooler waters (25 degrees Celsius) for a month, it recovered, albeit with a darker pigmentation compared to unheated corals. This suggests that resilient coral like S.pistillata can possibly bounce back during cooler winter months, even after enduring prolonged periods of heat stress.
However, researchers caution against relying solely on this resilience. With ocean temperatures projected to increase by 3 degrees Celsius by 2100, the ability of coral reefs to adapt predictably to climate models remains uncertain.
“survival is certainly the No. 1 vital thing for coral,but when they’re physiologically compromised,they can’t do that forever,” emphasizes Andrea Grottoli,co-author of the study and a professor in earth sciences at Ohio state. “So there’s a limit to how long these resilient corals can cope with an ever-increasing warming ocean.”
The research highlights the importance of understanding how warming waters alter coral growth and feeding patterns to inform long-term conservation efforts. Grottoli suggests focusing conservation efforts