Corals—considered the building blocks of ocean diversity—are experiencing the worst crisis in their 250 million year history caused by a rapidly warming planet. During the past two centuries, keystone marine organisms have been increasingly exposed to elevated sea surface temperatures. On top of this, they have fought a losing battle against anthropogenic pollution and overfishing. Recent research indicates that corals can quickly acclimatize themselves to shifting environmental circumstances. This incredible skill is even more remarkable considering the risks they are under.
Jessica C. Hankins, a leading marine biologist, pioneered coral research to the forefront of innovation. Her research highlights how these critical organisms are responding to increasing ocean acidity and warming ocean temperatures. She analyzed a pair of coral skeleton specimens. One originated from the Great Barrier Reef and is almost 200 years old, while the other, from the Coral Sea, is aged 115 years. These new findings reveal that corals are surprisingly able to retain their large, beautiful, mineral skeletons. Unfortunately, this resilience exists even in the context of a slow but steady increase in ocean acidity over the last 200 years.
The Pressing Threats to Coral Ecosystems
Corals are the bedrock of healthy marine ecosystems. They are important nursery grounds for most coastal marine life, serving as habitat and food sources for hundreds of marine species. Their very survival is threatened by cumulative stressors exacerbated by climate change. Rising sea surface temperatures are one of the biggest dangers. They have been responsible for escalating mass coral bleaching events. Between 2023 and May 15, 2024, it has been reported that at least 62 countries and territories were affected by widespread coral bleaching.
Additionally, anthropogenic forces play an undeniable role in the decline of coral reef ecosystems. Pollution from agricultural runoff and urban waste adds more toxic chemicals into marine ecosystems, increasing the pressure on coral ecosystems. These issues are compounded by unsustainable fishing practices. This prey on the already sensitive competition of reef ecosystems. Declining varieties of fish that rely on corals for protection from predators.
Together, the cumulative effect of these elements bundled together form an insurmountable storm that is leaving corals on razor’s edge. Should they continue to weaken and create less dense skeletons, it might set in motion an ecological domino effect of calamity. This can eventually lead to a near–global failure of marine ecosystems.
Investigating Coral Adaptation Mechanisms
Even with all the intimidating obstacles in their way, preliminary research headed up by Hankins been showing some encouraging correlations of resilience amongst corals. Using a cutting-edge imaging technique called Raman spectroscopy, Hankins found that the calcifying fluid that helps build coral skeletons had unique properties. This fluid is especially critical for laying down their hard biominerals. It might be just as important for their future survival in the face of rapidly changing environmental conditions.
That study made the interesting discovery that corals can recalibrate their calcification machinery. Perhaps most importantly, they provide a powerful defense against ever-increasing ocean acidity. Since the Industrial Revolution, ocean acidity has increased by nearly 40%. This increase is primarily due to the ocean taking in carbon dioxide emissions from human activities. The ability of corals to alter their calcifying fluid provides hope that they can withstand some of the adverse effects of climate change.
Hankins’ analysis of archived coral samples indicates that these organisms have shown a counterintuitive ability to adapt gradually over geologic timescales. This unexpected discovery highlights a new kind of resilience that could help corals persist in environments that are becoming more inhospitable.
Implications for Coral Conservation
The picture painted by these findings on corals’ ability to adapt reveals a clear need for further research and conservation initiatives. Unraveling the physiological and evolutionary mechanisms at work in corals that confer resilience will be key to making successful moves to guard these ecosystems. With each passing year, global temperatures hit new highs, and the effects on marine environments are alarming. With targeted coral conservation efforts, we can greatly improve coral health.
Continued action to reduce pollution and protect corals from destructive fishing practices is vital to ensuring these beautiful ecosystems thrive. Furthermore, building appreciation of what coral reefs contribute to society can continue to rally public support to build the urgency for coral conservation efforts.