Friend Feature: Bull Kelp Nereocystis luetkeana
Free diver, Snow Seychelle, slips into the magic of the kelp forest in the San Juan Islands. Image by Cy Scammel, Salish Sea In Focus
Bull kelp is buoyant enough to hold herons hoping for fresh fish hiding between blades. Image by Jeffrey Martel, Salish Sea In Focus
There is nothing not to love about kelp, the giant, golden brown seaweed in our cold Salish Sea. The way it sways like it’s dancing in the currents or how you can weave your way through it like a seal on a swim. On a seafaring adventure, you can take a big, juicy (and salty), vitamin-packed bite to tide you over (ha!) to the next meal.
Bull kelp may just be the best kelp of all! For starters, its scientific name, Nereocystis, means “mermaid’s bladder,” and there is so much more to explore! Peer through the layers of leaf-like blades into a kelp forest and see what wonders await.
Plants? Kelp are plant-like, but are they plants? You decide. Plants sit still (mostly). So does kelp. Plants turn water and carbon dioxide into sugar. So does kelp. Plants use sunlight as energy to drive that amazing photosynthesis thing. So does kelp. Plants create seeds from flowers or cones that break open and send down roots. That’s where the similarities end.
Animals? Instead of seeds, kelp release little, swimming critters called zoospores (zoo means animal) from pouches in their leaf-like blades. Yes, for part of the kelp lifecycle, they are tiny, free-swimming creatures. These divide into several cells and grow to get ready for fertilization. Then it’s time to settle down. Literally. They sink.
You might even say they put down some roots - but they don’t. Kelp grow a tangle of tissue called a holdfast that cements the little kelpling (not a real term, but I couldn’t kelp myself) to a hard surface, like rock, mussels, or wood. Holdfasts stick. It’s a simple job, but important, considering bull kelp can live where ocean currents rip along at 7 knots and crashing waves thrash against sea stacks.
A harbor seal, playing in the kelp, snuck up on photographer, Florian Graner, as he explored a kelp forest by Whidbey Island.
Sunshine = Sugar = Gigantic Growth
Where do kelp get water and nutrients if they have no roots? Through every part of their bodies. They are bathing in a sea of all the water and nutrients they need. Just add the bright sunlight of spring and summer and bull kelp grow. And how they grow! They can grow nearly a foot per day! All the way up to 118 feet (36 meters). And that’s just their stipe (stem). The blades extend another 3-4 meters (13 feet) beyond that.
Kelp have gas?
Kelp have gas. In fact, they need it. A gas-filled bulb at the top of the stipe helps them rise to reach the sun they need. What may surprise you is that the gas is poisonous. Carbon monoxide is made in kelp tissue and released into the bulb and hollow tube. You might have carbon monoxide detectors in your home to warn you. Why? Because it doesn’t take much to render a person unconscious. It turns out bull kelp have enough to do that and more! Yes, the rumors about bull kelp having enough poisonous gas to kill a chicken are TRUE! I learned this thanks to some research done by our friend, The Marine Detective. Click her link to find out what she discovered and what it has to do with an apartment-dwelling elephant in Alaska. You read that right.
Neither If you decided kelp are not plants nor animals, what are these strange beings? Like all other seaweeds, they’re algae. But they do form forests like trees of the sea.
Kelp Helps
Schools of herring shelter from predators in the cover of the kelp forest and lay their sticky eggs on its stipes and blades. Image by Florian Graner, Salish Sea In Focus
Bull kelp like to grow together and when they do they form kelp forests. Kelp forests slow down fast currents and shorten big waves, protecting our coastlines and sheltering life within.
Like a forest on land, kelp forests have layers and loads of life. For every layer, from the forest floor to the canopy, living beings find habitat.
Forest Floor Little animals, like worms, snails, and sea squirts, live between their toes (holdfasts) in the many hidey holes there. Urchins munch on every part they can reach.
Understory Rockfish, herring, salmon, lingcod, kelp crab, nudibranchs, and more cruise the understory.
Canopy Wildlife from sea otters to shrimp to tiny, lace-like communities of bryozoans find shelter and even some fun up near the sun.
An orca plays with a bull kelp stipe, hooked around its dorsal fin. Can you find a second orca in the forest? How about a third? Image by Christopher Teren
Kelp Forest Fun
Killer whales often dive into kelp forests to wrap a stipe around a fin, maybe just to feel that slippery-smooth surface slide along as they swim. Seals seek fish between blades, too, and play with the kelp when the fishing’s done.
Help the Kelp!
Remember how kelp absorb all they need from their seawater bath? Well, they absorb stuff they don’t need, too, like pollution. Testing kelp tissue for contaminants shows that they even take up some heavy metals. This can be dangerous for animals and people who eat kelp as part of their diet.
You too can take swim through the “mermaid’s bladders” like this mermaid, Snow Seychelle. What wonders will you find? Image by Cy Scammel
You can help the kelp (and people and wildlife) by keeping pollution out of the water. Take your car to a car wash or wash it over the lawn. Remember, nothing but rain down the storm drain. And use sea-safe cleaners and other products in your home. We all live uphill from the ocean so it’s our job to keep her safe!
Bull?
So what has bull kelp to do with bulls? Someone thought the stipes look like bull whips when they wash up, which you may be tempted to try out on your kid brother. But don’t. No matter how great the urge. Instead we recommend using them as jump ropes, try tooting your own horn, or try out your skills on a didgeridoo!