SAN DIEGO — Evolution works over thousands of years. Climate change It moves much faster.
This mismatch is killing off some of the planet’s most vital ecosystems, from California’s towering redwoods to the seagrass meadows along its coast, both of which store vast amounts of carbon and support complex webs of life.
Marine heat waves Forest fire record and Coastal development These systems push beyond their limits Climate changedriven by emissions of fuels such as oil and gas, is accelerating. An estimated 1 million species face extinction, many within decades, largely due to human activities such as habitat destruction, pollution and overuse of natural resources, according to a 2019 report by an intergovernmental scientific body of the United Nations.
Scientists are working to fill the gap through an emerging discipline called conservation genomics: sequencing an organism’s entire genetic blueprint to identify individuals with the right traits to survive drought, disease and other extreme climate events, and then using that information to guide restoration.
Coral reefs are among the first ecosystems in which these genomic tools are being used. Repeated marine heat waves have resulted, causing mass bleaching Destroyed coral reefs All over the world. By sequencing corals and the algae that live within them, researchers identified colonies that naturally tolerate high temperatures and began testing whether selective breeding and development of these more resilient corals could support Coral reef recovery.
In Southern California, researchers are applying this approach to eelgrass, a type of seagrass, where traditional restoration methods have faltered. The plant provides a habitat for fish, crabs, plankton and forage Migratory birds Carbon and methane – both greenhouse gases that cause global warming – are trapped in coastal sediments.
Conditions in San Diego Bays are changing. The water is warming up. Tide King The highest tides of the year, which makes climate change more frequent and intense, stir up sediments and reduce the light that reaches the sea floor. Development sends runoff into bays, adding to the murky waters.
As a result, efforts to replant what was lost fail in about half of the cases.
“Conservation genomics has become particularly important because the climate is changing right now — a plant that used to grow largely in San Diego Bay, now San Diego Bay may be too hot for it,” said Todd Michael, a research professor at the Salk Institute for Biological Studies.
In Mission Bay, Michael and his colleagues discovered a clue to improving these odds: naturally occurring hybrid eelgrass that outcompeted native species. The plant is a hybrid between the shallow-water Zostera marina eelgrass and the deeper-water Zostera pacifica, and has survived where both native species have struggled.
By sequencing its genome, the team identified genes associated with the plant’s circadian clock that remain active longer under low-light conditions, a pattern that scientists believe may help it photosynthesize more efficiently in turbid waters.
The results suggest that restoration can be improved by selecting or breeding eelgrass best suited to future conditions. But for now, this work remains largely experimental and has not yet been widely disseminated in the field. The researchers collaborated with ecologists at Scripps Institution of Oceanography to explore how these ideas could be applied in future restoration.
Redwood trees are among the tallest and oldest trees on Earth, and their forests store more carbon per acre than any other tree, according to a 2020 study by Save the Redwoods League and Humboldt State University.
While these trees evolved with frequent, low-intensity fires, today they are hotter and hotter devastating forest fires, Combined with drought, they cause increasing losses. Logging had an even greater impact: about 95% of old-growth redwoods were cut down, greatly reducing genetic diversity.
Scientists have already sequenced the redwood genome, a massive undertaking given its size, which is about nine times larger than the human genome.
However, researchers say the work is not just about restoring what was there before, but about preparing forests for a climate that no longer resembles the past.
“When one organism is adapted to a particular place at a particular moment, it may no longer be so,” said David Neal, a forest geneticist and distinguished professor emeritus at the University of California, Davis. “It may require different genetic variation to adapt to the new environment.”
Early analyzes have begun to link genes to traits such as drought tolerance and temperature adaptation, but researchers say more rigorous work is needed to confirm these links before they can be used to guide restoration. This work has been halted due to limited funding.
“It might be helpful, but it’s not a solution in and of itself,” said Karen Hall, distinguished professor of environmental studies at the University of California, Santa Cruz. “What should be the priority is reducing global warming Gas emissions“.
Genomic tools may help some species, especially long-lived species like redwood trees that cannot adapt quickly enough on their own, but they have limitations. Ecosystems depend on complex relationships between plants, animals, microbes and fungi. Engineering or selecting for climate-resistant traits in one species does not guarantee the survival of many other species that depend on it.
“Can you genetically engineer a few species that might be more tolerant? Sure. But that’s not an ecosystem,” Hall said. “We will not engineer our way out of climate change.”
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Follow Annika Hammerschlag on Instagram: @ahammergram.
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