Scientists are building a 'Noah’s ark' of California’s tide pools. It will live here in LA

On an overcast morning in July, marine biologist Greg Rouse knelt next to a large tide pool near La Jolla’s Bird Rock.

“This place is incredibly diverse in habitats,” Rouse said, scooping a sample of seawater into a plastic bag.

A few miles down the beach, in his seaside lab at the Scripps Institute of Oceanography, Rouse separated the sampled water into a petri dish.

At first glance it was just water and some floating ocean debris.

But when Rouse slid the petri dish under a microscope, hundreds of nearly-microscopic animals burst into life on a high-resolution monitor: shrimps and snails, pillbug-like isopods, worms of all sorts of different shapes, and at least one bright-orange sea slug.

Sampling tide pools like this is fairly routine for Rouse, but lately, it has been part of something bigger. Rouse is leading the first phase of an effort to document California’s intertidal ecosystems.

That means logging every organism found in the tidal seawater, sand and rocks from San Diego to the Oregon border over the next two years.

“It's a baseline of what is here right now,” Rouse said. “It's a shame we didn't do this 20 or 40 years ago. But in those times, we didn't really have the DNA technology and the cost efficiency that we have these days.”

The project, called the California Intertidal Biodiversity DNA Barcode Library project, is ambitious. Nothing of this scale has been attempted in the U.S. It’s being led by a coalition of top research institutions, including Scripps, the Los Angeles County Museum of Natural History, the California Ocean Protection Council and the Southern California Coastal Research Project.

The goal is to create a comprehensive picture of California’s tidal habitats by focusing on the algae and invertebrates that live in them, including their DNA profiles. Scientists say that will let them more effectively track changes in those ecosystems.

Scientists building the biological library are focused on the nearly microscopic invertebrates and algae that live in California's tidal regions, which are less well understood than more visible fish, birds and mammals.

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Lucas Brady Woods

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LAist

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The intertidal region is made up of the narrow strip of coastline that alternates between being submerged at high tide and exposed at low tide. It’s habitats are some of the most vulnerable to the effects of climate change, including rising water temperatures and sea levels.

The two-year project launched with $10 million in state funding earlier this year but kicked into high gear this summer.

Last month, Rouse led a group of dozens of scientists to the tide pools, where they pulled more than 7,000 samples from the area around Bird Rock.

“Anything we could see, we took. But also we took a lot of stuff you can't see back to the lab and had many people on microscopes finding all the tiny creatures,” Rouse said. “Because most of the diversity is actually too small to see.”

Testing is still underway, but so far the samples represent 1,600 species of invertebrates and algae, hundreds of which could be new to science.

Biological library housed in L.A. 

Once collected and analyzed at Scripps, the physical specimens and their DNA profiles will be sent to the L.A. County Museum of Natural History where they will be stored in a massive library.

The museum was chosen in part because it has the largest collection of invertebrates in the U.S., outside of the Smithsonian Institution.

The project will be focused on invertebrates and algae because fish, mammals and other big, visible animals have been sampled plenty. Scientists say there is a major gap in the understanding of the tiny tide pool organisms that play a key role in the wider ecosystem.

“It's all about a food chain … and we don't have a good grounding of who's eating whom,” said Regina Wetzer, curator of marine biodiversity at the Natural History Museum. “It's a whole cascade of networks that feed the larger things that are carnivorous fish or that are birds."

A nudibranch mollusk, a type of sea slug called Vassyeria, was one of the thousands of organisms collected recently in La Jolla. It's seen here under a microscope.

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Greg Rouse

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Scripps Institute of Oceanography

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Among the new species found by the recent tide pool sampling is this polychaete scaleworm, seen here under a microscope.

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Greg Rouse

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Scripps Institute of Oceanography

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Protecting the coast

Building this biological library is not just for the sake of expanding scientific understanding. It’s also practical.

Without a clear baseline to reference, said Dean Pentcheff, project manager of the Diversity Initiative for the Southern California Ocean, scientists have been largely operating in the dark.

“To responsibly manage the shore and manage our resources and manage the life on it, we need to know who's where and who's who,” Pentcheff said. “And right now, for the intertidal [zone], we don't know that.”

The DNA library will lay the groundwork for new, powerful tools scientists can use to monitor changes in the tidal ecosystem.

One of those is environmental DNA, or E-DNA, the biological detritus that naturally sloughs off organisms. Collecting samples of water or sand, and the E-DNA in it, can provide a quick snapshot of an ecosystem when compared to a baseline.

At L.A.'s Natural History Museum Regina Wetzer, left, a curator, and Dean Pentcheff, head of the Diversity Initiative for the Southern California Ocean, discuss the logistics of building the tidal "biolibrary."

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Lucas Brady Woods

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LAist

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“That's a list of all the organisms that are there, but you can't put a name to any of them unless you have a reference library to look it up in,” Pentcheff said. “So our job in this project is to cruise up and down the state and create that library of genetic reference sequences to enable environmental DNA to be used in the future.”

The library will also be designed to allow for different levels of DNA sequencing, from basic DNA profiles, called barcodes, that are quick and easy to produce, to much more complex profiles that provide detailed information on an organism.

Backed by California taxpayers 

The tools the project is expected to unlock have also galvanized the officials in charge of protecting the state’s marine environments.

“Where are invasive species showing up? What's happening with species range shifts as things migrate northward? Those are the kinds of questions that we can answer, start to answer with a lot of this information,” said Mike Esgro, a member of the California Ocean Protection Council who oversees the state’s Marine Protected Areas.

California’s Marine Protected Areas cover about 16% of California’s coastal waters. They are specific geographical areas in the ocean or around coastal estuaries designed to protect and conserve marine life and habitats.

Esgro hopes the DNA library, and emerging tools like E-DNA that rely on it, will improve how officials manage these places. For example, it could help officials better understand which ones are most vulnerable and identify additional marine environments that need state protection.

It could even help scientists figure out how to shift tidal habitats inland to compensate for rising sea levels.

He also wants to see continued collaboration with state agencies like the Ocean Protection Council and the California Department of Fish and Wildlife.

And he hopes the California project, which he calls the “Noah’s Ark of intertidal diversity,” can serve as an example. Scientists in California are already looking at other possible DNA libraries focused on insects and fungi.

“The climate crisis is very real. It's very urgent. We're seeing the impacts right now,” Esgro said. “And so I think adopting that kind of mindset of — ‘We gotta go big; we gotta swing for the fences’ — that's crucial.”