What Free Diving in a Kelp Forest Taught Me About an Overlooked but Incredibly Valuable Ecosystem
A photographer shares the epiphanies she has had while chronicling underwater jungles off the California coast
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The kelp forest is my favorite ecosystem on Earth. I first began diving into these nearshore waters off the California coast three years ago. Shortly after, I began taking my camera down with me to document the shifting ecosystem. Each time I submerge beneath the waves, my senses sharpen.
Sunlight filters through the kelp canopy, turning the water into stained glass, a masterpiece in motion. Schools of fish dance between the trees and sunbeams—like brushstrokes. Sea lions carve effortless arcs through the boundless blue. And in this wild gallery, the only thing I take is a photograph—light captured, nothing disturbed. Some say the camera creates distance, pulling us out of the moment, but I feel the opposite. When I photograph, I am more present, more attuned. The act of framing forces me to see. Poet Mary Oliver once wrote, “Pay attention. Be astonished. Tell about it.” In many ways, this feels like an ode to that sentiment.
The kelp forest is wild in a way few places still are. One moment, the water is clear, golden light spilling through the canopy. The next, a storm surge barrels through, tangling the fronds, turning the waters dark and thrashing. Free diving here is often a balance of persistence as well as surrender, but the kelp forest doesn’t ask for credentials, only a willingness to dive in.
This natural sanctuary is a space of learning, one that reveals itself in pieces. I have learned not just during the dives themselves, but in reading about the ecosystem and talking to researchers afterward./https://tf-cmsv2-smithsonianmag-media.s3.amazonaws.com/filer_public/f0/11/f0116788-b4df-44c1-a828-87acb0f11860/1_details_web.jpg)
Kelp forests are some of the most productive ecosystems on Earth. Giant kelp, a kind of algae, can grow up to 18 inches per day, and the trees reach more than ten stories tall at full growth. Among much else, the trees shelter marine life, capture carbon from the atmosphere and buffer coastlines from powerful waves.
But these underwater jungles are in trouble. For the last 50 years, kelp abundance has declined globally by 1.8 percent annually, and somewhere between 40 and 60 percent of the planet’s kelp forests have been degraded. Along the coast of California, where I free dive, some forest areas have seen a loss of more than 90 percent within only the last decade.
Kelp faces a rising tide of threats. Warming oceans lead kelp to produce fewer offspring that may grow slower. Unchecked sea urchin grazing can strip the forest into a barren, where biodiversity plummets. Nutrient pollution from land runoff can cloud the water, blocking sunlight vital for kelp growth, while excess nutrients fuel algal blooms that smother kelp and disrupt the ecosystem.
But still, the kelp forest remains a place of wonder. I return not just to witness and document its changes, but to learn from them. These are six of the greatest lessons it has taught me.
Every creature matters
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Each time I dive in, it feels as if the whole forest breathes. The kelp rises in towering columns, over a hundred feet tall, and the light passing through and around it appears in shifting layers of gold and green. A harbor seal pup may glide past, its dark eyes wide with curiosity, passing the smallest of turban snails clinging to the tree’s fronds. A school of fish can scatter as other fish species weave through the fronds like swallows through jungle vine.
“The complexity of a kelp forest matters,” says Ryan Elman Langendorf, a theoretical ecologist at University of Colorado Boulder. “Losing some species really can unravel an entire ecosystem.”
Langendorf is the lead author of a March study that highlights sea otters’ and other keystone species’ influence on ecosystems. Sea otters “are referred to as gardeners of the kelp forests, and other theoretical ecologists would add ‘engineers,’” he says. “I’ll add ‘wizards.’” Sea otters help keep kelp forests healthy by eating sea urchins, which would otherwise destroy the kelp. Without otters, urchin populations can explode, damaging the underwater jungles that provide food and shelter for countless creatures.
This place is vulnerable
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Urchins move slowly, but their destruction is swift. Without predators to keep them in check, says Laura Rogers-Bennett, a senior environmental scientist at the California Department of Fish and Wildlife, urchins devour the base of kelp and can turn towering forests into barren seascapes within a matter of seasons. She notes that in the waters north of San Francisco, purple urchin barrens now blanket the seafloor where there were once kelp holdfasts. What’s vanishing isn’t just the kelp but the life it shelters—the fish, the otters and more.
“It’s an incredibly important and an incredibly vulnerable system,” Rogers-Bennett says.
Ten or so years ago, a combination of an extreme warming event known as “the blob” back-to-back with a warm El Niño demolished the kelp forests north of San Francisco and led to a staggering 95 percent loss, Rogers-Bennett says. The algae has not recovered in the years since. She also highlights that fossil fuel emissions amplified this marine heat wave’s intensity and duration by trapping heat in the atmosphere.
When the marine heat wave hit, it weakened and killed off much of the Pacific coastline’s bull kelp. At the same time, populations of sunflower sea stars—the main predators of purple sea urchins—collapsed due to sea star wasting disease, which was worsened by the warmer waters. With fewer predators to keep them in check and little competition from other species, purple sea urchin populations exploded. These urchins now persist in a dormant state, waiting for new kelp to appear. However, their sheer numbers prevent kelp regrowth, as they consume any new growth before it has a chance to re-establish.
“Incidents like these [marine heat waves] are the trigger for that collapse and are projected to increase in frequency as well as intensity into the future,” says Rogers-Bennett. “We’re already seeing it now.”
The forest slows the sea
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Above the canopy, the ocean surges. But beneath the surface, the kelp holds the chaos at bay. The thick, rubbery blades absorb and soften some of the swell’s force. Without this buffer, waves would crash harder against the shore, stripping away sand and battering cliffs.
And while this place offers solace from email pings and trash trucks, the kelp forest is anything but silent. If you know how to listen, the jungle beneath the waves is alive with sound: the static-like crackles of snapping shrimp, the whooshes of the trees pulsing, the distant grumbles of low-frequency sea lion calls.
Many think of the ocean as the last quiet place. But even underwater, human noise is accelerating. The hum of ships, the sounds of construction and seismic blasts are disrupting ecosystems, and they can also be heard in the kelp forests.
This algae is a natural climate solution
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Each kelp blade pulls carbon from the water and locks it away in its twisting, sun-fed limbs. Like the Amazon rainforest, kelp and other seaweed can aid in carbon absorption. But they are not invincible, and as the kelp forests decline carbon remains in the sea.
“A lack of kelp forest really impedes the ability for oceans to absorb CO2 and store it in deeper water,” says Rogers-Bennett.
Scientists have found that warming temperatures speed up kelp decomposition. When the organisms break down faster, they release carbon back into the atmosphere, especially in warmer, low-latitude regions.
“With excess CO2 in the atmosphere and 71 percent of our globe consisting of oceans, we’re going to need to include the oceans in coming up with global climate solutions,” says Rogers-Bennett.
Some researchers are looking to kelp for help. Scientists at Woods Hole Oceanographic Institution are pioneering a climate solution by breeding heat-tolerant strains of sugar kelp, a marine crop that absorbs carbon dioxide and helps combat ocean acidification. By identifying and crossbreeding naturally resilient kelp populations with heat-tolerant strains, researchers are hoping to ensure the future of sustainable kelp farming. The algae offers enormous potential benefits, including for food production and biofuel development.
The little things have value
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Through my camera, I see the world in a series of moments, each frame a study in movement and light. Science, too, is built on details, on looking closer. Like photography, science requires examining an ecosystem through different lenses, focusing on different details, particularly as conditions shift. The kelp forest is a world of many layers: The sea lions gliding effortlessly through the canopy are just as important as the snail clinging to the side of a frond. And the jungle is packed with such creatures. Researchers in Norway found that there are upwards of 238 mobile macrofauna associated with the kelp in their waters, with an average density of almost 8,000 individuals per kelp. These tiny creatures, from crustaceans to mollusks, inhabit various parts of the kelp and demonstrate the ecosystem’s complexity.
Kelp can inspire
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Almost 200 years ago, the photographer Anna Atkins showed us that art and seaweed science could intertwine, capturing the fleeting beauty of marine life in deep-blue cyanotypes. Long before her, Indigenous coastal communities were weaving their own artistry from the marine world. They turned kelp into fishing lines, intricate baskets and textiles. Today, artists like Oriana Poindexter carry this lineage forward, using light and water to reveal in prints what the ocean holds.
Through art, we are reminded to stop, admire and care for this living, breathing part of the planet. It’s why I keep returning, camera in hand, to dive again and again, to capture the kelp and its delicate ecosystems, to inspire others to protect what sustains us.