From 2013-16, the California coast was hit with a marine heatwave known as “The Blob” – a hundreds of miles-long patch of unusually warm water that devastated plant and animal life in the Pacific Ocean.
Among the hardest hit was a species of kelp known as bull kelp, an underwater plant that, in addition to pulling carbon dioxide from the atmosphere, provides food and habitats for other marine life. In fact, said Filipe Alberto, an associate professor of biological sciences at UWM, The Blob and associated ecological changes rendered bull kelp in danger of local extinction in northern California.
In July, Sea Grant appointed Alberto and other scientists to do something about it.
Sea Grant is a collaboration between the federal government, California state government, and California universities to create knowledge, products, and services benefiting the economy and environment. Funded by the California Ocean Protection Council and the California Department of Fish and Wildlife, Sea Grant chose Alberto and his team to be one of six projects to receive a combined total of $2.1 million in funding to help the recovery the dwindling population of bull kelp.
Alberto already had a potential solution started.
“It’s like a seed bank. Part of the life cycle of a kelp involves a stage that is microscopic, which is called the gametophyte. There are ways, in the lab, of preserving these gametophytes for a very long period,” he explained. “This buys us time to understand the methods to put the species back and if it’s a good idea to put the species back. (If it is), we will have this ‘seed bank’ to help with the restoration.”
Alberto has long studied the genetic diversity of several species of kelp. Even before receiving the grant, he and his (now-graduated) graduate student, Lily Gierke, had been collecting samples across the bull kelp distribution in 2017 to analyze its genetic diversity. Gametophytes had also been collected from Washington in collaboration with the Puget Sound Restoration Fund. Those collections will form the basis of the seed bank, as well as samples that are currently being gathered.
The second part of his project involves repeating that genetic analysis. Alberto and his team, which includes researchers from UC-Santa Cruz and the University of Southern California, want to compare the bull kelp’s current genetic diversity with the samples collected back in 2017 to see if it has changed with several more years of ecological degradation. Finally, the genetic analysis will be enhanced as the team sequences a reference genome for bull kelp, which will allow for a population genomics analysis.
“One of the things that genomics allows you to do is understand how this genetic differentiation between the samples that we collect is associated with different environmental factors,” Alberto said. “Having the genome also allows us to understand if different specimens might be differentially adapted to different environments. Often, it’s possible that the individuals collected further south where average waters are warmer might naturally select and adapt to that type of environment, just like people might have in different parts of the world in different climates.”
Even so, he warned, temperature is not the whole story – there are several factors contributing to the decline of bull kelp, and using genomics might help pinpoint which genetic markers will help bull kelp survive a variety of environmental obstacles.
That way, “in the future when people wonder how to restore a particular site, we will have not just the gametophyte banks to source those efforts, but also the knowledge to say, ‘In that location, we should use this particular material,’” Alberto added.
Restoring the bull kelp in central California is important because those kelp forests have some of the richest genetic diversity in the plant’s range, and genetic diversity can help any species evolve and survive in changing environments. Bull kelp can grow from central California up the coast to Alaska.
“Across all of that space, you’re going to have pockets of different genetic backgrounds, so it’s always a tragedy to lose one of these pockets,” Alberto said. “Especially in the south where there is so much genetic diversity and so much potential for this species, to have all of this southern range disappear … is disturbing.”
By Sarah Vickery, College of Letters & Science