The Giant and the Bug: Kelp Restoration with Applied Microbiology

A New Friend

“What do you do for a living?” a woman asked, sitting across from me at a local bar.

“I’m a marine biologist,” I replied, watching her apathetic expression transform into wonder.

Her reaction was a familiar one. “Marine biologist” is often an answer children give when you ask them what they want to be when they grow up.

“How does one become a marine biologist? What does a day in a marine biologist’s life look like? Do you swim with dolphins?” she asked, not pausing long enough for me to reply.

I laughed and explained that, unfortunately, dolphins don’t exactly enjoy being around humans. Then I spent the rest of the night explaining my career to this perfect stranger.

How to Become a Marine Biologist

Now you, the reader, might be wondering the same thing. How does one become a marine biologist? I can tell you that there is no single path to get here. The only thing that matters is you have to really want it.

As for my own journey, I didn’t know what I wanted to pursue until my mid-20’s! I was in a pre-med program but never felt passionate about the career. I worked in a cancer lab, Starbucks, retail, and restaurants. I even had a brief stint as a medical assistant at a gastroenterology practice. In short, I had no clue what I wanted to do with my future. All I knew at the time was that I wanted to help people, and that I enjoyed science and discovery.

I eventually joined a lab working with blind Mexican cavefish. There, I generated the very first cavefish transgenic lines in existence. (Transgenic means that DNA from one organism has been introduced into another, unrelated organism.) This accomplishment enthralled me; it was the first step on my path to become a scientist. Then out of the blue, I asked a question that steered me toward the field of marine biology…

 

Where are the biofuels?

One day while sitting in traffic, I noticed something: dark plumes of exhaust puffing out of vehicle tailpipes alongside lanes and lanes of traffic, stretching far into the horizon.

Have you ever thought about the finite nature of fossil fuels such as gasoline? I have–and I certainly did in that moment. The more I thought about it, the more dumfounded I became.

Why haven’t we tackled this problem yet? Are we going to sit and wait as societal collapse inches closer and closer by the day? What about the transition to more sustainable options such as biofuels, which are produced from renewable biological sources? There must be some sort of crop we could grow to use for energy… right?

These questions swam around in my mind until I decided I needed to figure out a way to get involved in making a change.

 

My Way or the Kelp Highway

I searched for marine biology Ph.D. programs that could help with this issue and landed on giant kelp.

Why giant kelp, you ask?

1. It is one of the fastest-growing organisms on earth, with a growth rate of up to 2 feet per day. That means plenty of fast-growing biomass for biofuel material.
2. Giant kelp cultivation doesn’t need fertilizer or water; you can simply grow it in the ocean and harvest when necessary.
3. Giant kelp captures millions of tonnes of carbon dioxide as it grows. Carbon sequestration at this scale can help reduce the effects of climate change on our planet.

With these characteristics, I believed that giant kelp was a fine contender as a biofuel source. However, this grand vision started to fade after I started my Ph.D. The more I learned about giant kelp, the more it became clear that widespread use of it as a biofuel was many years away from coming to fruition. 

 

A Kelpless Planet

After sifting through years of publications about giant kelp, I began to grasp the dire status of kelp forests. With predatory otter populations reduced, purple sea urchins have consumed entire forests down to the bare substrate. High ocean temperatures have devastated kelp populations and still prevent them from recovering. And coastal development and urban runoff have destroyed coastline habitats.

The extinction of kelp forests can also cause events that intensify the effects of environmental change, like dominoes falling in a line. Without kelp, the ocean has less oxygen and more acidity, which in turn is harmful for other marine organisms. Kelp forests are also a nursery habitat, meaning that they provide food and cover for juvenile fish and other species. No kelp means fewer juveniles surviving to adulthood. Once I learned these facts, my research focus shifted from biofuel production to giant kelp conservation and restoration.

Of course, many scientists before have had this same realization. Kelp restoration actually began in the 1700s in Japan. The four main techniques involve transplantation, seeding, grazer control, and artificial reefs. Unfortunately, each of these methods have inherent limitations, including financial restrictions and scalability. These restoration techniques have not fundamentally changed since the 20th century, so it’s now time to reconsider these traditional methods. We need to explore alternative and more sustainable ways to restore kelp forests.

 

You Reap What You Sow

Did you know that kelp produces “seeds”? Its reproductive tissue releases spores, which develop into gametophytes–structures comparable to seeds from plants. This unique trait makes it possible to create and maintain kelp seed banks, which can reduce reliance on wild kelp sampling and help preserve native biodiversity. By storing gametophytes, seed banking is making restoration techniques more sustainable and useful in today’s ecological environment. It’s important to note, however, that the long-term effects of kelp gametophyte storage are still not fully understood. 

 

A Microscopic Problem

My lab at USC, led by Professor of Biological Sciences Sergey Nuzhdin, hosts a seed bank of gametophytes from along the California coast. When I first joined, these samples had been in storage for five years. One of the first tasks I attempted was breeding these gametophytes, and I quickly learned that this wasn’t easy.

I found that these gametophytes had lower fecundity–or reproductive capability–than fresh samples. One possible cause: microbes. Over the past five years, the microbial community living on these kelp samples had shifted, becoming less diverse and dominated by a single species. Because microbes play a vital role in maintaining gametophyte health and quality, these microbial changes carry serious implications for reproduction. We need further research to figure out optimal processes for seed-based restoration, including how to reintroduce the missing microbes. This is the research I’m now focused on. 

A Day in the Life

Now that you’re all caught up, let me tell you about a typical day in my life as a researcher. First, I embark for the Wrigley Marine Science Center (WMSC) on Catalina Island. I chose to base our research here because the area around WMSC has minimal human activity. According to peer-reviewed literature, less human activity means less harmful bacteria.

Once my team arrives, we gear up and jump into the crisp, crystal-clear turquoise ocean to begin our scientific dive. We collect giant kelp blades at various depths and locations.

We then bring these samples to an onsite laboratory at WMSC for processing. We rinse the blades with sterilized seawater, swab, and incubate the microbes on petri dishes. In a couple of days, we have a collection of kelp-associated bacteria to work with. Once I know the identity of these bacteria and their growth rates, I use them as kelp inoculants. 

Inocu-what?

“Inoculant” is just a fancy word for something you introduce to another organism. Remember when I mentioned earlier that long-term stored seeds were losing microbiome diversity? I want to see what happens if I take some “bugs” (what some microbiologists call bacteria) from the environment and introduce them back to our seeds.

We already do this with agricultural crops! For example, farmers often inoculate soil with special bacteria that enhance crop yield and growth. My theory: the addition of certain bacteria to giant kelp gametophytes will improve viability.

Let’s Talk About Kelp, Baby!

Thanks to the Wrigley Institute Graduate Fellowship, I can test this theory. Generous support from the Bertics Fellowship Fund has provided opportunities that wouldn’t have been possible otherwise. I get to work on Catalina Island, mentor an undergraduate researcher, and purchase critical lab supplies.

So far, we have sequenced 24 different species of bacteria from Chalk Cove and Descanso Beach on Catalina Island. Soon, we will be ready to do the following steps: 

1. Inoculate our gametophytes with these bacteria
2. Monitor our samples over two weeks, focusing on the change in gametophyte size
3. Use a special imaging system at Children’s Hospital L.A. to measure chlorophyll fluorescence, a way of determining gametophyte growth rate and health
4. Send the best-performing samples for metagenomic sequencing (metagenomic = a type of genetic analysis that covers all microbial species present). This will allow us to quantify how much each kelp sample’s microbial community has changed since inoculation.
5. Conduct a breeding experiment. This will show if the addition of bacteria increases the likelihood of kelp reproduction!

 

It’s Getting Hot in Here

Let’s say this works exactly as planned. It would mean that our laboratory-maintained kelp seeds can now breed with a higher chance of success. However, this process alone won’t solve our restoration problem. There’s no guarantee of survival post-transplantation. With oceans warming at an alarming rate, what if all this hard work still ends with the kelp dying because of rising temperatures?

That’s why we’re also running heat-stress tests at the same time. Gametophyte seeds thrive at around 13°C/55°F, but using the same parameters, we’re testing our process on a group kept at a scorching 25°C/77°F. At this temperature, we’ve observed gametophyte health decline significantly. If even one of our bacteria can help alleviate the effects of heat stress, it would be an incredible breakthrough.

 

In the End…

This is just the beginning of transformative research like this. Results from this project can only answer a few questions about restoration. As many scientists say–albeit redundantly–further research IS needed.

I am grateful to be a Wrigley Graduate Fellow, especially during times like these. I have had the opportunity to interact and work with remarkable peers in my cohort. I take pride in working with and inspiring bright young researchers.

And most importantly, being a Wrigley Institute Fellow has allowed me to reach YOU! If you’ve read this far, it’s safe to assume that you now care a little bit more about our kelp forests. I hope I’ve sparked your curiosity in marine biology because you, too, can make a difference in marine science. Simply talking about giant kelp can shift peoples’ perspectives about marine biology. Perhaps you’ll inspire someone to pursue a career in this field. All it takes is one question to change the world.

So, my new friend, to restate my point: no, I don’t swim with dolphins (nor do I want to). But I am trying to save a Giant with a Bug.

Learn more about Bernadeth’s research journey:

Bernadeth Tolentino is supported by the Victoria J. Bertics Graduate Fellowship Fund.