The Power of Kelp

Increasing acidification in the Puget Sound and Hood Canal is taking a toll on the species that inhabit those waters. The PMEL Carbon Group worked with the Puget Sound Restoration Fund (PSRF) to help investigate the power of sugar kelp to improve seawater conditions locally. With increasingly corrosive conditions ahead, the project tested the efficacy of using native vegetation to buffer the pH of seawater in places with important shellfish resources. The 5-year project implements a key recommendation of the Blue Ribbon Panel on Ocean Acidification with funding from The Paul G. Allen Family Foundation. Please read the PSRF's Summary of Findings to learn more.



Transcript of the video above:

JOTH DAVIS: So here we are in the Pacific Northwest. We're sitting in North Hood canal, and we are just thinking about all the wonderful uses of seaweeds. I have this grand vision that we'll replace all the corn grown in Iowa with kelp grown on the Pacific coast.

00:21 MEG CHADSEY: It's probably one of the best possible things you can farm in this kind of environment. You don't have to water it, apply pesticides or fertilizers or anything. It's literally an input free crop.

00:33 JOTH DAVIS: We're growing sugar kelp out here. It's just one of many species that are available for the grower in the Pacific Northwest. We actually sit in the largest diversity of seaweeds practically in the world.

00:45 MEG CHADSEY: And we're just starting to realize all the benefits of growing kelp in this region.

00:56 JOTH DAVIS: So, I've been a shellfish farmer now for about thirty years. And about ten years or so ago, we really started noticing in the hatchery environment that the oyster larvae just weren't thriving. And it all turned out to be issues associated with this emerging global problem of ocean acidification.

01:14 MEG CHADSEY: Our human carbon dioxide emissions are literally acidifying our oceans. And this is a global problem, but it's particularly bad here in the Pacific Northwest. And here in Puget Sound, we've got vulnerable animals like oysters and other shell forming organisms. They're having a hard time maintaining their shells as the seawater that they live in becomes more corrosive. So, in 2013 the Paul Allen Family Foundation challenged people to come up with out-of-the-box ways to address ocean acidification. And Joth Davis and I, and Betsy Peabody with the Puget Sound Restoration Fund, and a couple of other scientists, we got together and pitched an idea to this contest that was based on the concept of phytoremediation. Kelp, which is a very fast growing algae, has the power to absorb a tremendous amount of carbon dioxide and other nutrients out of the water as it grows. So we wanted to see if we could harness this power of kelp to actually mitigate the effects of ocean acidification locally, here, in a small part of Puget Sound, about the size of a shellfish farm.

02:26 JOTH DAVIS: So behind me in the middle section is where we grow kelp. And on the perimeter you see long strings of black buoys. From those we're hanging shellfish, and oysters specifically.

02:39 MEG CHADSEY: And we recruited a crack team of scientists and aquaculture experts to conduct an experiment at Joth's farm. This team installed a football field-sized array of submerged grow lines, planted it out with kelp seedlings, and deployed sensors to detect changes in sea water chemistry that might come about as a result of the growing kelp. The kelp grew really well, but it turns out the currents here were too fast for it to measurably improve seawater chemistry. So a key take home from this experiment is that if we're hoping to use kelp to mitigate ocean acidification locally, it's really critical to look for optimal conditions, and monitor sites to make sure that mitigation is actually happening. We also learned that when you're cultivating kelp, you've gotta be thinking ahead. By the end of our first growing season, we had an enormous crop. What we didn't have was a plan for what to do with it. Fortunately Eli Wheat, an agroecology expert at the University of Washington and the owner of SkyRoot farm on Whidbey Island nearby, came to the rescue. Where we saw 14,000 pounds of homeless kelp, Eli saw captured carbon and nutrients. So Eli offered to have us deliver the entire harvest to his farm and then he would do experiments on how to incorporate that kelp into the soil to improve productivity.

04:01 ELI WHEAT: My background as an ecologist is in thinking about systems. And so when we started farming here, we wanted to take our understanding of ecology to approach the farm from a systems-thinking perspective. And so the kelp project just really fit into that bigger vision of nutrient recycling on the farm. It's like this incredible cross-ecosystem connection. So, you're growing kelp in the water to reduce ocean acidification and benefit bivalve growth. And we can then take that kelp, which has been so beneficial in the marine environment, and bring it onto our farm and use it to increase the productivity of our farm as a system. So it felt like, wow, this is a totally amazing opportunity!"

04:54 JOTH DAVIS: There's no downside of growing seaweed. You could grow for biofuels. You can grow seaweeds for fertilizers, compost. And I think, honestly the best use is growing seaweeds for food!

05:06 MEG CHADSEY: Chefs and consumers are clamoring for this new exciting sustainable delicious product.

05:12 JOTH DAVIS: And who knows what's going to happen in the next 20 years? The OA problem hopefully will get better. And in the meantime, I think that growing seaweeds has all these co-benefits that we hope will assist in culturing shellfish, like oysters. We know it sucks up carbon. We know it sucks up nitrogen. And we definitely feel when we harvest kelp from this site we're making a difference and that means a lot to me as a long term shellfish farmer in the area. And um, as I said, more power to kelp!


    Thank you to the many partners powering recovery actions:
  • NOAA, Pacific Marine Environmental Laboratory
  • Washington Sea Grant
  • University of Washington, Applied Physics Laboratory
  • Puget Sound Restoration Fund
  • Salish Sea Greens
  • Washington Department of Natural Resources
  • Environmental Analysis System
  • Aqua Model
  • Hood Canal Mariculture
  • Southern California Coastal Water Research Project


Thank you to the Paul G. Allen Family Foundation and the US Navy for supporting the Hood Canal kelp/acidification investigation, and to the Puget Sound Restoration Fund, Washington Sea Grant, and the Nereus Foundation for funding this video.