When Oriana Poindexter first moved to San Diego in 2013, the ample kelp forests that lined the coast were somewhat of a hindrance. The peaceful glide of her longboard along the waves often came to an abrupt halt when her trailing leash became entangled in the thick seaweed beneath the swell. The kelp forest was abundant, dense with tall trees, flourishing with sea life.

In time, the kelp would become the central focus of not only her passions, but also her career path. Poindexter, who grew up in Laguna Beach, had earned her undergraduate degree in visual arts from Princeton University and loved using her camera as a tool for exploring artistic subjects. While she was studying at the Scripps Institution of Oceanography in 2014, a marine heat wave known as “the blob” emerged off the West Coast. This warm weather system certainly came with its negative consequences, but the unusually balmy waters also provided pleasant temperatures for plunging into the deep. Poindexter, who had always been a strong swimmer, started to free dive every day in the kelp forest, Nikonos camera in hand. The kelp forest became her muse, and the species weaving between the trees became her constant companions. Through her stunning images, Poindexter recorded ecosystem shifts she witnessed in the depths.

Oriana Poindexter
Poindexter examines a piece of giant kelp. Avery Schuyler Nunn

In 2018, Poindexter learned to process her digital negatives differently through attending a cyanotype workshop. Cyanotype printing, one of the oldest forms of chemical processes for film development, uses a light-sensitive solution to produce cyan-blue prints. For the workshop, Poindexter brought in an image she had taken of a friend diving through the kelp forest. Upon processing the film into a cyanotype, she found that the details of the forest, what she most connected with underwater, were lost. While photographing, the forest felt larger than life. As replicated on the small cyanotype paper, the trees seemed measly and trifling. But six months after the workshop, Poindexter had an epiphany: The prints didn’t need to be small. She could expose the algae directly on huge pieces of paper.

Kelp on Treated Cyanotype Paper
Poindexter places kelp on treated cyanotype paper for processing under sunlight. Avery Schuyler Nunn

Poindexter began collecting pieces of kelp on her morning dives and laying the strands onto paper to create life-size cyanotypes. With the seaweeds’ textures in greater detail and at full scale, the art pieces became quintessential records of the forests beneath the surface.

Giant Kelp
Giant kelp collected by the artist while free diving off Casas Beach, California Oriana Poindexter

In 2021, after more than five years working as a fisheries economics analyst, Poindexter left her job to focus on art full time. While she found that the intricate numbers-oriented profession offered a congenial balance to her artistic pursuits, she increasingly yearned for her creative outlet. Since then, she has collected numerous kelp species from around the globe and hosted art shows to convey to others on land the happenings of the forests. We caught up with Poindexter in San Diego for a dive and to discuss her work and motivations.

Giant Kelp Holdfast
Giant kelp holdfast collected by the artist on Boomer’s Beach, California Oriana Poindexter

Q: What is it about creating cyanotypes that most compels you above other art forms?

A: I got really into the cyanotypes because they let me have that whole physical and tangible experience of finding something, collecting it and bringing it home to make something beautiful with. And then have that object be such a good representation of the thing that I had found. By noting the time and place of where all of this is coming from, I can create a record of what’s there, what’s not there, how things are shifting. I can still have that whole connection of exploring my environment, finding something interesting, bringing it home. It captures stuff in the kelp that you really can’t get in a photograph—like the kind of hair-like extensions and the details of the blades—because you can’t really get the scale of the kelp when it’s downsized into a photograph.

Surfgrass
Surfgrass found drifting while the artist free drove off Point La Jolla Oriana Poindexter

Q: How does cyanotype printing work exactly? What’s your process?

A: They make pre-made cyanotype paper, but I just buy the chemistry in bulk and treat my own paper. You basically make a light-sensitive emulsion out of two iron salts, which I mix up myself. Then you paint the emulsion onto the paper in subdued light. There can’t be any UV light coming in while you treat the paper, so I’ll usually paint all my paper the night before I plan to use it. Then I’ll have an idea in my head of what canvas I have available when I go diving: Am I looking for a big piece or something small? Then in the morning I’ll go diving and come back to my dried paper and lay the collected kelp over the paper, arrange it and bring it outside into the sun to expose it to direct sunlight. It works best with higher UV indexes, where the exposure time only needs to be about seven to ten minutes. The last step is to rinse it in water, which can be freshwater or saltwater.

When I’m traveling, I enjoy taking prepped paper with me and making prints right on the beach. Then I have this record of something without having to take that thing away from the ecosystem.

Feather Boa Kelp
Feather boa kelp collected by the artist while free diving off Point La Jolla Oriana Poindexter

Q: It’s interesting that your art form also feels very scientific—involving chemistry and temperature and recordkeeping. Are there ways in which you expand or experiment with that?

A: Yeah, it’s like this combination of science and allowing the magic of chance to play into things, and I think that’s where the beauty really comes from. You can prepare yourself and the paper in all these ways, but it’s really up to whatever the ocean decides to provide you with that day, how much wind there is during printmaking, etc. There’s these elements of the natural environment that participate in ways that sometimes can feel frustrating, but is what I find really interesting about it all.

I’ll often take the piece of kelp that I use to create the image and make a toning bath out of it, which is essentially like making a tea. I’ll soak the whole print in that. Then you can get some pretty cool color alterations, which is interesting to me because it’s another way of taking that specimen object and recording another one of its qualities—the pigment within the algae. And I’ve ended the kelps’ life taking these pieces from the ocean; it’s not going to be able to continue growing. So it’s another way for me to use it and feel like I’m doing right by it.

Algae
Algae collected by the artist while free diving off Windansea Beach, California Oriana Poindexter

Q: What drives you to keep doing this work? Is there a deep source of inspiration you come back to?

A: I think it’s this combination of an urge to document and create a record of the places you’ve been, which any photographer understands. But doing it over and over again in the same place builds into this more comprehensive picture. And the fact that this specific place has been documented so well for so long by so many people is really compelling to me as well.

In the 1800s, Anna Atkins was the first woman to make cyanotypes of seaweed. And there’s this album that was put together in 1905 or 1906 by Ellen Browning Scripps and her sister Virginia of teeny-tiny seaweed pressings. They were just collecting them from the beach or tide pools and pressing them. Botany is something that it was historically “OK” for women to be interested in scientifically, before women could really be involved in science. So the cyanotypes of seaweed in this specific place to me connects this history of women and the way they were allowed to explore their environment in the past, and now that has, of course, been totally blown out of the water, and we can explore in whatever way we want.

I’m still using the same methods and subjects, but in a bit more of an expanded way. And I just love being in the water and the freedom of movement. There’s definitely something there about the ocean specifically and being able to expose yourself to it in the way that you can when free diving—there’s a reason I must keep doing it.

This interview has been lightly edited for length and clarity.

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Avery Schuyler Nunn is a California-based science journalist who specializes in oceanography and environmental shifts beneath the surface. Since she earned her master’s degree in journalism from Columbia University, her words and photographs have been featured in Smithsonian, Popular Science, Grist and more.