A group of scientists at a research centre in Hawaii are experimenting with assisted evolution. They are attempting to grow “super coral” that is able to withstand hotter, more acidic ocean conditions, expected as a result of global warming.
As the concentration of carbon dioxide and other greenhouse gases in the atmosphere increases, the acidity of the ocean increases as well. Stressful conditions such as changes in pH or fluctuations in temperature can cause coral to bleach. When this happens, coral releases all of the symbiotic algae it contains, becoming white or bright yellow in the process. This in itself isn’t a death sentence: if the coral is kept away from things like pollutants, overfishing, and other strains, it can recover. However, bleaching does makes coral more susceptible to disease, and can increase the likelihood that the coral will die.
Bleaching has only happened a few times. Before 2014, the last time coral in Hawaii bleached was 1996. However early this October there was a global bleaching, which the National Oceanic and Atmospheric Administration described as extensive and severe. That event was the second consecutive bleaching of Hawaiian coral in the last two years, which does not bode well for the coral. It may not recover for decades, if at all.
In order to prevent coral from dying in the future, researchers at the Hawaii institute of Marine Biology have been taking samples of healthy coral back to their lab and slowly exposing them to water that is slightly more stressful. The theory is that over time the corals can become physiologically primed to tolerate additional stress. They are also selectively breeding resilient strains of coral that they find in the ocean, in hopes of perpetuating the resilient genes in offspring. The researchers are then going to transplant these resiliently designed corals into the bay, and monitor them to see if they are able to grow normally and reproduce, even in stressful conditions.
At the University of Miami in Florida there is also research being done on different strains of algae; some strains of algae are more prevalent in corals that are heat stressed, which suggests that they are better able to survive stressful conditions, and can help the coral survive as well. These researchers are looking into the possibility of intentionally putting certain strains of algae in coral reefs to help them survive, although as of yet it is unclear whether this would be possible, given that in the wild environmental conditions may cause corals to favour certain types of alga.
Nevertheless, not everyone agrees that tinkering with nature is the best way to help the coral. For one, selective breeding could narrow genetic variation and thus potentially reduce the capacity of coral to adapt in the future. While it might enhance specific traits, this could come at the expense of other traits. For example, higher resiliency could lead to slower growth. There are even some who say that assisted evolution is ethically not sound; that it is like “playing God”.
Whether or not they agree on assisted evolution, scientists do agree that the coral must be protected, and emphasize the importance of reducing destructive human activities that are leading to pollution, overfishing, and global warming.
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