Climate Gratitude: California’s Kelp Forests

Now, more than ever, it’s crucial to acknowledge and appreciate the ecosystem services that our beautiful planet provides us. These ecosystem services enable all living things to function and allow the world to keep spinning despite all the chaos that humanity throws its way. Today, I would like to say “thank you” to one of these many services by highlighting the resiliency, capabilities, and current struggles of the California kelp forests.

Many of us may be familiar with kelp and seaweed from swimming in the ocean and experiencing the fronds of aquatic plants brush against our legs. I will admit that it’s frightened me on more than one occasion. But kelp is much more than that! Kelp are brown macroalgae that live in cool, shallow salt waters—because of their dependency on light for photosynthesis, they rarely grow deeper than 49–131 feet under water (NOAA). 

Kelp forests across the planet are richly biodiverse habitats, as the giant aquatic plants offer shelter to flora and fauna from predators and protection from storms, rough water, and currents. Because of this, kelp forests are rich feeding grounds for native species and offer beautiful snorkeling and scuba diving opportunities. Overall, as ecosystems, kelp forests are as important as coral reefs and mangrove forests to the overall health of the ocean (Bryce, 2021). Much worth celebrating! There are beautiful kelp forests all over the world, but I’d specifically like to take this opportunity to highlight California kelp forests in particular. 

Known as the “Sequoia of the Sea,” California’s kelp forests are among the tallest, fastest-growing kelp forests in the world. For example, “bull kelp” forests in Northern California grow an average of four inches per day and reach heights over 100 feet (Park, 2021). These productive kelp forests are home to California’s state saltwater fish, the Garibaldi, and contribute to fishing and tourism industries from Eureka to San Diego. According to the Nature Conservancy, kelp forests in California “pump more than $250 million into the state’s economy each year by way of commercial fishing, recreational diving, wastewater treatment and more.”  But perhaps the most important benefit that California’s kelp forests provide are their array of ecosystem services, especially carbon sequestration. 

Kelp forests temporarily store staggering amounts of carbon—around 20 times more per acre than forests on land. Kelp acts as a carbon conveyor, meaning carbon absorbed by kelp is transferred to sediments for sequestration once washed out to sea or when incorporated into animal tissue after being eaten. Therefore, California’s kelp is quite important to the aquatic and atmospheric side of the carbon cycle. In fact, seaweeds around the world sequester 200 million tons of CO2 every year—kelp forest ecosystems account for about 5% of that sequestration process (Eger et al. 2023).

However, these underwater forests around the world are at risk due to warming water temperatures, ocean acidification, and invasive species population booms. This process is exemplified in the coastal waters of Northern California where kelp forests are on the verge of collapse. A study by the California Department of Fish and Wildlife shows how kelp cover was decimated in Northern California from 2008-2016. The speed of this habitat loss is deeply shocking and concerning.

Let’s explore the factors that led to this demise. From 2011 to 2015, Northern California’s kelp forests experienced a wave of stressors that demolished local populations (Park, 2021). A sea star wasting disease demolished sunflower sea stars living in shallow coastal waters. These sunflower sea stars are some of the world’s largest and fastest sea stars, but 90% of their global population has been wiped out in the last decade by “sea star wasting syndrome” which breaks down the limbs and body of a sea star into mush (Zuckerman, 2023). In the wake of their absence, purple urchin populations exploded in a 10,000% increase along the northern coast of California since 2014 (Zuckerman, 2023). Purple urchins consume kelp and without a predator, like the sunflower star, to keep them in check, the empty space on the ocean floor becomes barren of plant life and filled with congregations of purple urchins. A final factor that is harming kelp populations are warming waters – which came to California in a marine heatwave in 2014–2015. Warming waters provide less nutrients to fuel the growth of kelp and contribute to kelp bleaching which disrupts the photosynthesis process. Together, sea star wasting syndrome, urchin population increases, and warming waters have destroyed kelp populations. It’s up to humans to help recover them.

Luckily, California’s kelp forests are not being ignored when help is most needed. In 2024, state agencies administered over $5.8 million in funding for five kelp research and restoration projects (Eberle, 2024). California is also working to expand marine protected areas to conserve and protect kelp habitat. In addition to state efforts, a huge grassroots and NGO-led effort to defeat urchin populations is in process. This video from the Nature Conservancy highlights one of those activists, Grant Downie, who is a commercial urchin diver in Fort Bragg, California. Downie goes on dive expeditions to collect and kill invasive purple urchins and give kelp a chance at returning. Scientists like Kalani Ortiz of California Polytechnic Humboldt are studying kelp growth and what effective reforestation could look like. Both preventative and restorative approaches are necessary to revive these magical underwater ecosystems that are so critical to carbon sequestration and biodiversity.

This blog post is about expressing gratitude for California’s kelp forests in addition to highlighting the challenges they are facing and the solutions being implemented up and down the state. Not all of us can easily access the kelp forests of California or do much to help them (at least in hands-on restoration). But there are other ways to appreciate and show our gratitude to kelp, if you are interested. By supporting marine conservation efforts—such as California’s 30×30 movement, you can support efforts to expand protected coastlines and kelp habitats. There are also many NGOs all over the west coast and around the world working to revive kelp forests that need the help of local volunteers or donations. More fun ways to engage with kelp include visiting your local aquarium or snorkelling among the ecosystems to understand and appreciate their beauty. I grew up snorkeling in the kelp forests of southern California, and it was during these experiences of ocean exploration that I grew my affection and respect for coastal ecosystems. I feel so much gratitude towards kelp forests, and the state-wide efforts to revive them give me so much hope! I hope they do the same for you.

 

Works Cited

Bland, Alastair. “As Oceans Warm, the World’s Kelp Forests Begin to Disappear” YaleEnvironment360, 20 November 2017, https://e360.yale.edu/features/as-oceans-warm-the-worlds-giant-kelp-forests-begin-to-disappear

Bryce, Emma. “The Case for Conserving Kelp.” Dialogue Earth, 24 September 2021. https://dialogue.earth/en/ocean/18733-the-case-for-conserving-kelp/

Eberle, Ute. “Five projects awarded over $5.8 million in funding to research how to restore California’s vital kelp forests”. Sea Grant California, 19 February 2024. 

Nat Commun 14, 1894 (2023). https://doi.org/10.1038/s41467-023-Krause-Jensen, D., Duarte, C. Substantial role of macroalgae in marine carbon sequestration. Nature Geosci 9, 737–742 (2016). https://doi.org/10.1038/ngeo279037385-0.

NOAA. “What is a Kelp Forest?” National Ocean and Atmospheric Administration. 6 June 2024. https://oceanservice.noaa.gov/facts/kelp.html 

Park, Jane. “Kelp: California’s Coastal Forests.” UCDavis Coastal and Marine Sciences Institute, 12 January 2021. https://marinescience.ucdavis.edu/blog/kelp-californias-coastal-forests#:~:text=Kelp%20forests%20support%20California%20coastal,species%20than%20urchin%2Ddominated%20barrens.

Rogers-Bennett, L., and C. A. Catton. “Marine heat wave and multiple stressors tip bull kelp forest to sea urchin barrens.” Scientific Reports. 9:15050. 2019.

Zuckerman, Catherine. “The Vanishing Forests”. The Nature Conservancy, 26 May 2023. https://www.nature.org/en-us/magazine/magazine-articles/kelp-forest/