Spreading the Love About Seaweed

Like most farmers, Cindy West of Moonstone Oysters is ready for work before the sun is up. It’s early April, and she and her crew are dressed in plenty of layers against the chill.

There’s chatter about last night’s Bruins game as they load equipment. Among the crew of four is Lindsay Green-Gavrielidis, a post-doctoral fellow from the University of Rhode Island’s Department of Natural Resources. Despite the early hour, she is smiling and greets West warmly.

Just as the sun begins to glow over the water, the group boards, and the boat heads to the first stop—a patch of kelp in Point Judith Pond. It’s all part of a URI research project into an important trend: seaweed aquaculture.

“My role is serving as seaweed expert,” Green-Gavrielidis explains. “I grow the material in the lab, work with farmers to plant it, monitor the growth, teach them about what to look for and how to measure growth, and help with the harvest.”

The research is the result of a grant URI obtained in 2017 to learn about kelp farming. Green-Gavrielidis says worldwide farming of various seaweeds is increasing 5 to 10 percent annually, and local farmers have expressed an interest in getting involved with the trend. She points to the health benefits of consuming seaweed.

“A lot of people say it’s better to eat lower on the food web, and it can’t get any lower in the ocean than seaweed. They don’t have a lot of fat in terms of things we think of as ‘bad’ in your diet. They’re not exactly equivalent to something like spinach, but some people do refer to them as a ‘sea vegetable.’ Kelp, in particular, is very well-known as being a source of iodine. Protein comprises up to 50 percent of the volume of nori, the Japanese weed used in sushi. That’s one of the highest content ratios we know. It also contains a lot of vitamin C as well as taurine, an important amino acid,” she says.

“They all have their healthy aspects, and they’re all sustainable, as long as if you’re buying wild harvest they’re using a sustainable methodology. Buying farmed product is the best way to go in terms of buying a sustainable product. The largest crop of seaweeds are the kelps in terms of weight, and that is overwhelmingly used for human food, including miso soup and kelp salad.”

The crew deftly maneuvers around in the 25-foot boat, which is crowded with baskets, line, kelp bags, and an open well in the center. Each of the morning’s sites comprises eight 240-foot lines. Each rope is strung along the bottom and is upheld by a series of buoys. The lines are pulled in by hand at first, then hooked to a winch that stands about 6 feet high at the stern. As the line is retrieved, the crew slices off the kelp blades and places each in the baskets. It doesn’t take long for the deck to have all the traction of an ice rink.

“The project is designed to set up six farms across Rhode Island, each with different conditions, including varying hydrodynamics, nutrient content, and depth,” Green-Gavrielidis says.

“The theory is that if we grow them in varying conditions and measure the growth and output, we can use the information that we gather to create a model for the best conditions to grow kelp. In theory, we may be able to construct maps that will be available to farmers to help them choose the most productive regions in the bay.”

Green-Gavrielidis has been involved with the entire process of the experiment. The first part involved scuba diving to obtain the raw material. The blades she harvested were brought to a lab and slightly dried; that stressed the seaweed, forcing it to release its spores. From there, the spores were placed in 20-gallon tanks, where they later attached themselves to PVC tubes wrapped with cotton line. After about six weeks of careful monitoring, the apparatus was ready for placement in open water.

Once a month, Green-Gavrielidis checked on the collection. She collected samples and measured length by making a hole, like a paper punch, in the kelp blade. Her research revealed that a blade can grow several inches in a few days. The monitoring began in late fall and continued until the early spring harvest.

Aboard the Moonstone Oyster boat, Cindy West is concerned about the forecasted wind increase as well as the tide, and she phones another team to come and help at this site. Soon the area is a hive of activity: knives slicing through the kelp fronds, orange baskets filling with the harvest, and black plastic bags to hold the bounty. Those are quickly passed to the second boat, which soon fills from stem to stern. West smiles and quizzes the crew on pop music trivia but pushes them to keep moving. “Work and talk, work and talk,” she calls.

This batch will go to a processing plant in Maine. The trimmings, smaller scraps of kelp, will be used for fertilizer. The longer blades will be used in creating noodle products, and some will be processed and frozen into blocks to augment smoothies and yogurt.  

Green-Gavrielidis has braced against the chill by wrapping herself from head to toe in warm clothes and foul weather gear. She harvests a particularly long blade of kelp and a big smile shows through all the layers. “Look how beautiful this is!” she calls.

She has high hopes for this form of aquaculture.

“I think that it is a good alternative to growing nutritious food for a growing population in the future. It has less impact than crops grown on land, where there is competition for space or for water. It has its own challenges such as climate change. But in terms of agricultural land space, we don’t have a whole lot more that we can use, so in the future it would be good to explore some of these methods of producing food.”

by Hugh Markey
Photographs by Dana Smith