Seaweed Farming, Kelp Aquaculture, Sushi Roll Gardening...

A thriving kelp forest (© NOAA)

No, no one actually calls it "sushi roll gardening". It is officially known as both seaweed farming and kelp aquaculture, and it has the potential to help combat some of our world's most dire issues.

So what exactly is kelp aquaculture? Simply put, it is the growing and farming of seaweed. The process requires a farmer to place polyps (seeds) or juveniles of kelp onto ropes which are then driven out via boat to a designated farm zone next to the coast. The ropes are then dropped into the water, hung horizontally, and suspended in the water using buoys which is held in place with an anchor. Rope lengths can vary from only a few meters long to hundreds of meters long depending on the size of the farm. In order to protect the lines from wave action and passing boats, a weight mechanism is used to hang the ropes below surface level. Once the kelp is grown, farmers use machinery or their hands to pull the ropes back in the boat and bring their harvest back to shore to dry and sell.

Example of long line kelp farming (Grebe et al. 2019)

Kelp can be grown year round and takes almost no upkeep, it just grows on its own without the need of fertilizers, constant oversight, or even water. And it doesn't grow slowly either. Kelp, on average, can increase its mass by 10x in a matter of 6 to 8 weeks! That means that a plant weighing 100 grams at the start of the growing process would turn into a plant weighing 1 kilogram by the end of the 6 or 8 week period. For reference, that tomato plant that you've been attempting to grow in your backyard takes about 10 to 12 weeks to produce a mature tomato to use for your signature homemade salsa.

Great, so we know what seaweed farming is now, how to it works, and that it's efficient. Why would anyone care about growing seaweed?

Because seaweed farming can help to save our planet. Kelp is capable of absorbing massive amounts of carbon emissions to reduce the effects of climate change making it an extremely valuable carbon sink. While removing CO2 from the atmosphere, kelp simultaneously produces oxygen for us to breathe. Besides removing pollutants from our waters and atmosphere, kelp farms also create habitats for threatened and endangered species, provide a natural resource that can be used as food and in various products, and it can help to benefit the economies of coastal communities where it is implemented. It's a win in every aspect, so why not begin advocating for this industry in your town?

Harvesting Kelp in Maine (© Atlantic Sea Farms)