Sea Sponge

Shelby Penn is passionate about cleaning up the ocean and thinks that one of the ocean’s most unassuming life forms, seaweed, can help. Shelby is a grad student at the Phycology Lab at Moss Landing Marine Labs. She credits her Northern Virginia childhood with sparking a love of nature and leading her on adventures to Hawaii, Alaska and now to California where she is also the Assistant Dive Safety Officer at MLML. Shelby talks about how marine algae may be the perfect sponge for toxic pollutants like mercury, seaweed superpowers, and how a phycologist helped save a staple of the sushi industry.

What sparked your passion for the ocean and marine science?

Shelby Penn as a guide for UnCruise Adventures in Southeast Alaska.

Photo credit: Jasmine Poland

Shelby Penn: As far back as I can remember, I always had a passion for the health of the environment around me. It actually started with the woods surrounding my house, where I grew up in Northern Virginia. As I got older and discovered my passion for the ocean and marine science, I began learning about the Great Pacific Garbage Patch and the impacts trash and pollution was having on the marine environment. It wasn't until I moved to Catalina Island after graduating from college that I discovered seaweed. California has more species of seaweed than any other place in the world, making it a great place to study these organisms!

Already seaweed is used in many everyday food and cosmetic items, and we are continuing to understand its dynamic role in the environment. The increasing uses of seaweed are what led to my interest in studying these organisms and those applications.

What have you learned about seaweed and sea lettuce that has surprised you?

Ulva Lactuca, (Wikimedia)

SP: That is such a tough question because there is just so much! Sea lettuce, as well as many other species of algae, are remarkably resilient. They can survive for periods of desiccation, or being dried out, and can survive in a range of salinities. Seaweed also don't seem to be drastically affected by lower concentrations of toxins in the surrounding water. There are species like acid weed that produce sulfuric acid and kelps that produce pheromones to help in their own reproduction.

And red algae actually have two completely different life stages that scientists used to think were two different species! After World War II, Kathleen Mary Drew Baker was studying the Nori life cycle, when it disappeared from her tanks and was replaced by what scientists at the time thought was a separate species, Conchocelis. Because her tanks had been separated from the open ocean, contamination was not possible and Baker realized that the Nori and Conchocelis were actually the same species, just two different life stages of Nori. Kathleen Mary Drew Baker's discovery helped save the Nori industry in Japan! 

Let’s talk a bit about ocean pollution. What happens in the wild when seaweed accumulates these chemicals? How does it affect the marine food web? 

Photo credit: Claire Crowther

SP: These questions are something that scientists are only just starting to understand. We have known for some time that algae and seaweed can accumulate chemicals from the surrounding water, but we are only just beginning to understand how this accumulation affects the rest of the food chain. Some metals, like mercury, are well known to biomagnify at the top of the food chain, but this research has focused primarily on open ocean, or pelagic, ecosystems. The toxins and metals that accumulate in the nearshore environment haven't been largely considered until the last 10 to 20 years. These questions are what I am hoping to start understanding in my own research.

How would a seaweed clean up work?

SP: At this point, the concept of using seaweed for pollution cleanup is relatively new in the ocean. If we could develop a strategy to wash and collect these toxins from the algae, then it might be possible to use the algae like a filter in areas with increased chemical pollution. Currently, microalgae biofilms are used to help treat the effluent from wastewater treatment plants, so I could see a similar strategy being used in saltwater environments. However, in order to be most effective, it is important to understand why certain species of algae have a higher capability to accumulate chemicals and other toxins. This information would help us make more informed decisions in the bioremediation process. If we could develop a strategy to wash these chemicals from the seaweed, it is possible that seaweed could be used for the production of hydrogen gas or as a biofuel.

Is there any potential for seaweed to help with microplastic pollution or oil spills?

SP: Given the unknown potential for seaweed in bioremediation, using seaweed in the context of microplastic accumulation or oil spills can't be ruled out. We are just starting to understand how widespread microplastics are in the marine environment; this is partially due to our sampling ability of these incredibly small particles. For example, we are finding microplastics are carried to the arctic via trade winds, so I wouldn't be too surprised to find them sticking to the algae. In regards to oil spills, currently bacteria are used to help with the degradation of oil spills, but we might learn something more through the bacteria that are found on the outside of different seaweed species.

Cover shot: Shelby Penn in North San Francisco Bay. Photo credit: Claire Crowther