Today, people are generally aware of climate change and the fact that it is slowly killing different organisms across the planet to the point of extinction, and the sad truth is that much of this damage is irreversible; however, it is important to note that all hope is not lost.
While we as humans contribute to rising sea levels, acidification, and temperatures, determined marine species adapt to increasingly harsh environments to survive. On an island by the name of Ofu, in American Samoa, researchers like geneticist Stephen R. Palumbi study coral reefs that defy scientific predictions by surviving ever-increasing temperatures.
Despite shocking adaptations, these species are running out of time, and without human intervention, even the most impressive efforts on behalf of nature will only delay, never prevent, the inevitable.
In his 2014, lecture entitled Ocean Species Respond to Climate Change, Palumbi dives into the amazing discovery of heat resistance in corals, as a direct response to increasing ocean temperatures. Having persevered through multiple mass extinctions, it is unsurprising that coral species hold secret weapons for survival, but Palumbi and his teammates know all adaptations have limits. As a result, the team set out to discover how certain corals are resistant to bleaching, a byproduct of rising ocean temperatures in most corals.
Unbeknownst to many, corals are animals, complete with a skeletal system and a layer of tissue. On the outside, corals often appear tan or brown; however, this colouring is not natural to corals exclusively, but rather it comes from a species of microscopic dinoflagellates that live in a symbiotic relationship within the cells of a coral host.
Known as symbiodinium, these organisms are photosynthetic, meaning they contain chloroplasts for generating energy from sunlight. Providing 75–80% of the energy that corals need to conduct the essential functions of life, this symbiotic relationship is critical to the survival of corals.
Unfortunately, rising temperatures over recent years have led to the symbiodinium producing undesirable levels of oxygen, and coral cells react by ejecting these organisms. When this happens, corals lose their colour and appear white, hence the term "coral bleaching." Once bleaching occurs, corals can no longer build their skeletons, and they begin to die.
To observe how some corals continue to grow in increasing ocean temperatures, Palumbi’s lab conducted an experiment in which corals were studied in high-temperature environments. The findings showed the shocking result that while some corals experienced bleaching, others acclimated to their new climates.
As a geneticist, Palumbi focuses on the specific genes that enable some corals to resist changes in heat better than others, as his lab believes that harbouring the growth of heat-resistant corals will promote adaptation to climate change over upcoming generations. Right now, the Ofu lab is focused on protecting their coral nursery and encouraging the survival of these fragile organisms, but this alone is not enough.
While acclimation and adaptation continue to break barriers of predicted survival, no life form is invincible, and the rate of climate change is rapidly increasing. As we pump CO2 into the atmosphere, the ocean becomes more acidic, having increased by 26% over the last few decades.
Corals are not alone in their suffering; acidification prevents the formation of shells, impairs fishes' central nervous systems, and ultimately disrupts the very delicate balance of our marine ecosystems. In fact, carbon emissions are responsible for the destruction of thousands of organisms across our planet, causing harm in countless ways.
From the Arctic Circle to the small island of Ofa, generations of marine life have fought climate change, but time is running out for even the most resilient species. Coral bleaching is just one of many observable effects of pollution and climate change at the hands of human civilization. While scientists like Palumbi work to protect vulnerable species from the dangers of pollution, we as a society must fight to lessen our carbon emissions and remove these threats altogether.
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