[ad_1]
Reports on coral reefs these days focus on everything we could lose in our lifetime. The extinction of corals would affect hundreds of species, including ours. According to an estimate from the World Wildlife Fund, coral reefs provide nearly $ 30 billion annually in goods and services that people depend on, including fishing, tourism and coastal protection. The increasingly frequent heat waves associated with climate change are decimating living corals, leading to some projections that corals could disappear in a few decades. Their disappearance would be a disaster for one of the world's most diverse and economically important ecosystems.
But are we really in danger of losing so quickly the reefs of the world? The answer depends on how quickly corals can evolve – and here there is room for more optimism.
A common belief about evolution is that it always happens slowly. In fact, profound changes in natural populations can occur for only a few generations. For example, scientists have documented changes in lizards adapting to periods of cold weather where even a single blizzard brings substantial and lasting change to the population.
Such rapid evolution requires certain ingredients. One of the most important is to have a large population and to adapt to various conditions in the places where this population lives. Such populations already contain many genetic mutations useful for the nature to choose. As the environment changes, natural selection drives the rapid spread of these mutations in the population and future generations. The members of the population without these mutations die.
What is happening on the reefs of the world is "a sacred event of natural selection," says scientist Terry Hughes, who conducted a study on massive coral murders at the Great Barrier Reef. Many corals die, but within each species, some survive. My own research has found that rapid evolution can support corals for another century and perhaps even longer.
This phase gives us time to act. Despite the adverse effects of climate change on coral reefs, the situation is less desperate than many predictions suggest, but only if we choose effective and scientifically viable approaches to save the reefs
. would never really work. For example, trying to replace the natural evolution by bringing in corals that we think are the strongest and best suited to the breeding labs would never reach a fraction of what natural selection could do . Only the wide variety of genetic mutations available in nature leads to rapid and effective evolution. Equally erroneous are the ideas that heat-tolerant "super corals" can be "formed" (rather than evolved) or genetically engineered using new technologies capable of modifying DNA. There is no evidence that such training can benefit future generations of corals, and we do not know enough about how coral genes manage to build them significantly.
We should rather think about how to facilitate rapid change. genetic mixing and matching possibilities. "Assisted migration", a method of moving corals between environments, would do just that. For example, already warm reef corals could be moved to cooler reefs to help propagate mutations for heat tolerance. Crossing the corals from different parts of the lab and planting their offspring would further accelerate the process of genetic mixing. Currently, long-distance movement of corals is prohibited, but efforts are already underway to lift this ban in international guidelines for coral restoration.
More radical assisted migration measures may be needed in places like the North Caribbean. . On these reefs, juveniles of many of the most important reef-building species have not been seen for decades. Without reproduction, these corals disappear before our eyes. In these places, we should consider saving the reef even though we can not save its species by importing corals from the Indo-Pacific, where the breeding cycle still works well.
It does not matter, helping the reefs to save themselves can only be part of the solution. If the warming continues unabated, the genetic variation will eventually exhaust and all the corals will disappear. Ending global warming by reducing carbon emissions is the best way to help our coral reefs and the many lives that depend on them.
Mikhail Matz is Associate Professor of Integrative Biology at the College of Natural Sciences of the University of Texas at Austin
[ad_2]
Source link
